Mativ (MATV) S-4/ARegistration of securities issued in business combination transactions (amended)

As filed with the U.S. Securities and Exchange Commission on May 18, 2022

Registration No. 333-264676

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

AMENDMENT NO. 1 TO

FORM S-4

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

SCHWEITZER-MAUDUIT INTERNATIONAL, INC.

(Exact Name of Registrant as Specified in Its Charter)

100 North Point Center East, Suite 600

Alpharetta, GA 30022

Telephone: 1-800-514-0186

(Address, including Zip Code, and Phone Number, Including Area Code, of Registrant’s Principal Executive Offices)

Ricardo Nuñez

Executive Vice President, General Counsel and Secretary

SCHWEITZER-MAUDUIT INTERNATIONAL, INC.

100 North Point Center East, Suite 600

Alpharetta, GA 30022

Telephone: 1-800-514-0186

(Name, Address, including Zip Code, and Telephone Number, including Area Code, of Agent for Service)

With copies to:

Approximate date of commencement of proposed sale of the securities to the public: As soon as practicable after this Registration Statement is declared effective and upon completion of the merger described herein.

If the securities being registered on this form are being offered in connection with the formation of a holding company and there is compliance with General Instruction G, please check the following box.  ☐

If this form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act Registration Statement number of the earlier effective Registration Statement for the same offering.  ☐

If this form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act Registration Statement number of the earlier effective Registration Statement for the same offering.  ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act.  ☐

If applicable, place an X in the box to designate the appropriate rule provision relied upon in conducting this transaction:

Exchange Act Rule 13e-4(i) (Cross-Border Issuer Tender Offer)  ☐

Exchange Act Rule 14d-1(d) (Cross-Border Third-Party Tender Offer)  ☐

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

The information in this joint proxy statement/prospectus is not complete and may be changed. These securities may not be issued until the Registration Statement filed with the U.S. Securities and Exchange Commission is effective. This joint proxy statement/prospectus is not an offer to sell these securities and does not constitute the solicitation of an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

PRELIMINARY—SUBJECT TO COMPLETION, DATED MAY 18, 2022

MERGER PROPOSED—YOUR VOTE IS VERY IMPORTANT

To the Stockholders of Schweitzer-Mauduit International, Inc. and the Stockholders of Neenah, Inc.:

On March 28, 2022, Schweitzer-Mauduit International, Inc. (which we refer to as “SWM”) and Neenah, Inc. (which we refer to as “Neenah”) entered into an Agreement and Plan of Merger (which, as amended from time to time, we refer to as the “merger agreement”) that provides for the combination of the two companies in a merger of equals. Under the merger agreement, Samurai Warrior Merger Sub, Inc., a wholly owned subsidiary of SWM, will merge with and into Neenah, with Neenah continuing as the surviving corporation and a wholly owned subsidiary of SWM, in a transaction we refer to as the “merger.”

The boards of directors of SWM and Neenah (which we refer to as the “SWM board of directors” and the “Neenah board of directors,” respectively) have each unanimously approved the merger. Pursuant to the terms and subject to the conditions set forth in the merger agreement, at the effective time of the merger, each outstanding share of Neenah common stock, par value $0.01 per share (which we refer to as the “Neenah common stock”), will (other than certain shares owned by SWM or any of its wholly owned subsidiaries or Neenah or any of its wholly owned subsidiaries) be converted into the right to receive 1.358 shares (which we refer to as the “exchange ratio” and such shares, the “merger consideration”) of SWM common stock, par value $0.10 per share (which we refer to as the “SWM common stock”).

Although the number of shares of SWM common stock that each holder of Neenah common stock (which we refer to as the “Neenah stockholders”) will receive is fixed, the market value of the merger consideration will fluctuate based on the market price of SWM common stock and will not be known at the time Neenah stockholders vote on the merger or SWM stockholders vote on the share issuance. Based on the $30.23 closing price of SWM common stock on March 25, 2022, the last trading day before public announcement of the merger, the exchange ratio represented approximately $41.05 in value for each share of Neenah common stock. Based on the $                closing price per share of SWM common stock on                 , 2022, the latest practicable trading day before the date of the enclosed joint proxy statement/prospectus, the exchange ratio represented approximately $                in value for each share of Neenah common stock. We urge you to obtain current market quotations for shares of SWM common stock (currently traded on the New York Stock Exchange under the trading symbol “SWM”) and shares of Neenah common stock (currently traded on the New York Stock Exchange under the trading symbol “NP”).

We estimate that, upon completion of the merger, Neenah stockholders as of immediately prior to the merger will collectively own approximately 42% of the outstanding shares of the combined company immediately after the merger, and holders of SWM common stock (which we refer to as the “SWM stockholders”) as of immediately prior to the merger will collectively own approximately 58% of the outstanding shares of the combined company immediately after the merger (in each case, on a fully diluted basis and without regard to the fact that immediately prior to the merger certain stockholders may own both SWM common stock and Neenah common stock).

SWM will hold a special meeting (which we refer to as the “SWM special meeting”) of the SWM stockholders virtually, via live webcast on the Internet at www.cesonlineservices.com/swm22_vm on June 29, 2022, at 8:00 a.m., Eastern Time. At the SWM special meeting, the SWM stockholders will be asked (i) to approve the issuance of SWM common stock, pursuant to the terms of the merger agreement, in an amount necessary to complete the merger and the other transactions contemplated by the merger agreement (which we refer to as the “SWM share issuance proposal”), and (ii) to consider and vote on a proposal to approve the adjournment of the SWM special meeting from time to time, if determined by the chairperson of such meeting to be necessary or appropriate, including adjournment to permit further solicitation of proxies in favor of the SWM share issuance proposal or to ensure that any supplement or amendment to this joint proxy statement/prospectus is timely provided to SWM stockholders (which we refer to as the “SWM adjournment proposal”).

The SWM board of directors has unanimously (i) approved and declared advisable the merger agreement and the transactions contemplated thereby, including the merger, (ii) determined that the merger agreement and the transactions contemplated thereby are fair to, and in the best interests of, SWM and its stockholders and (iii) resolved to recommend that the SWM stockholders approve the SWM share issuance proposal.

Neenah will hold a special meeting (which we refer to as the “Neenah special meeting”) of the Neenah stockholders virtually, via live webcast on the Internet at www.virtualshareholdermeeting.com/NP2022SM on June 29, 2022, at 9:00 a.m., Eastern Time. At the Neenah special meeting, the Neenah stockholders will be asked (i) to consider and vote on a proposal to approve and adopt the merger agreement and the transactions contemplated thereby, including the merger (which we refer to as the “Neenah merger proposal”), (ii) to consider and vote on a non-binding advisory proposal to approve the compensation that may be paid or become payable to the named executive officers of Neenah that is based on or otherwise relates to the merger (which we refer to as the “Neenah compensation proposal”), and (iii) to consider and vote on a proposal to approve the adjournment of the Neenah special meeting from time to time, if determined by the chairperson of the meeting to be necessary or appropriate, including adjournment to permit further solicitation of proxies in favor of the Neenah merger proposal or to ensure that any supplement or amendment to this joint proxy statement/prospectus is timely provided to Neenah stockholders (which we refer to as the “Neenah adjournment proposal”).

The Neenah board of directors has unanimously (i) determined that the merger agreement and the transactions contemplated thereby, including the merger, are advisable, fair to and in the best interests of Neenah and its stockholders, (ii) approved and adopted the merger agreement and the execution, delivery and performance by Neenah of the merger agreement and the transactions contemplated thereby, including the merger, and (iii) recommended that Neenah’s stockholders approve the merger proposal.

The enclosed joint proxy statement/prospectus describes the Neenah special meeting, the SWM special meeting, the merger, the documents related to the merger, including the merger agreement, and other related matters. Please carefully read the entire joint proxy statement/prospectus, including the “Risk Factors,” beginning on page 38, for a discussion of the risks relating to the proposed merger.

Each of our board of directors unanimously recommends that stockholders vote “FOR” each of the proposals to be considered at the respective special meetings. We strongly support this combination of our companies and join our boards in their recommendations.

John D. Rogers Non-Executive Chairman Schweitzer-Mauduit International, Inc.		William M. Cook Non-Executive Chairman Neenah, Inc.

Neither the U.S. Securities and Exchange Commission nor any state securities commission has approved or disapproved of the securities to be issued in the merger or passed upon the adequacy or accuracy of this joint proxy statement/prospectus. Any representation to the contrary is a criminal offense.

The date of this joint proxy statement/prospectus is May 20, 2022, and it is first being mailed or otherwise delivered to the SWM stockholders and the Neenah stockholders on or about May 23, 2022.

NOTICE OF SPECIAL MEETING OF STOCKHOLDERS

To the Stockholders of Schweitzer-Mauduit International, Inc.:

On March 28, 2022, Schweitzer-Mauduit International, Inc. (which we refer to as “SWM”) and Neenah, Inc. (which we refer to as “Neenah”) entered into an Agreement and Plan of Merger (which, as amended from time to time, we refer to as the “merger agreement”) that provides for the combination of the two companies in a merger of equals. Under the merger agreement, Samurai Warrior Merger Sub, Inc., a wholly owned subsidiary of SWM, will merge with and into Neenah, with Neenah continuing as the surviving corporation and a wholly owned subsidiary of SWM, in a transaction we refer to as the “merger.”

SWM will hold a special meeting of holders of common stock of SWM (who we refer to as “SWM stockholders”) virtually via live webcast on the Internet at www.cesonlineservices.com/swm22_vm, on June 29, 2022, at 8:00 a.m. Eastern Time (which we refer to as the “SWM special meeting”), to consider and vote upon the following matters:

SWM has fixed the close of business on May 20, 2022, as the record date for the SWM special meeting and any adjournment or postponement thereof. Only SWM stockholders of record at that time are entitled to notice of, and to vote at, the SWM special meeting, or any adjournment or postponement of the SWM special meeting. During the SWM special meeting, SWM stockholders will be able to examine the list of the stockholders entitled to vote at the SWM special meeting by following the instructions on the live webcast. SWM stockholders may attend the SWM special meeting, access the stockholders list, submit questions and vote their shares via the Internet during the meeting by visiting www.cesonlineservices.com/swm22_vm. In order to attend the virtual meeting, you will need to pre-register by 8:00 a.m. Eastern Time on June 28, 2022 by visiting such website. To enter the SWM special meeting, SWM stockholders will need the control number that is printed on their proxy cards. SWM recommends that SWM stockholders log in at least fifteen minutes before the meeting to ensure that they are logged in when the meeting starts. Online check-in will start shortly before the meeting on June 29, 2022.

Approval of each of the SWM share issuance proposal and the SWM adjournment proposal requires the affirmative vote of a majority of the shares of SWM common stock which are present in person (via the Internet) or by proxy at the SWM special meeting and entitled to vote thereon.

The SWM board of directors has unanimously (i) approved and declared advisable the merger agreement and the transactions contemplated thereby, including the merger, (ii) determined that the merger agreement and the transactions contemplated thereby are fair to, and in the best interests of, SWM and its stockholders and (iii) resolved to recommend that the SWM stockholders approve the SWM share issuance proposal. The SWM board of directors unanimously recommends that SWM stockholders vote “FOR” the SWM share issuance proposal and “FOR” the SWM adjournment proposal.

Your vote is very important. SWM and Neenah cannot complete the merger unless SWM’s stockholders approve the SWM share issuance proposal.

Regardless of whether you plan to attend the SWM special meeting in person (via the Internet), please vote as soon as possible by following the voting procedures described on the proxy card.

SWM will not transact any business at the SWM special meeting, except such business as may properly be brought before the SWM special meeting or any adjournments or postponements thereof by or at the direction of the SWM board of directors.

The enclosed joint proxy statement/prospectus provides a detailed description of the SWM special meeting, the merger, the documents related to the merger and other related matters. We urge you to read the joint proxy statement/prospectus, including any documents incorporated in the joint proxy statement/prospectus by reference, and its annexes carefully and in their entirety.

BY ORDER OF THE BOARD OF DIRECTORS

Ricardo Nuñez Executive Vice President, General Counsel and Secretary Schweitzer-Mauduit International, Inc.

NOTICE OF SPECIAL MEETING OF STOCKHOLDERS

To the Stockholders of Neenah, Inc.:

Neenah, Inc. (which we refer to as “Neenah”) will hold a special meeting (which we refer to as the “Neenah special meeting”) of holders of common stock of Neenah (who we refer to as “Neenah stockholders”) virtually via live webcast on the Internet at www.virtualshareholdermeeting.com/NP2022SM, on June 29, 2022, at 9:00 a.m. Eastern Time to consider and vote upon the following matters:

Neenah has fixed the close of business on May 20, 2022, as the record date for the Neenah special meeting and any adjournment or postponement thereof. Only Neenah stockholders of record at that time are entitled to notice of, and to vote at, the Neenah special meeting, or any adjournment or postponement of the Neenah special meeting. During the Neenah special meeting, Neenah stockholders will be able to examine the list of the stockholders entitled to vote at the Neenah special meeting by following the instructions on the live webcast. Neenah stockholders may attend the Neenah special meeting, access the stockholders list, submit questions and vote their shares via the Internet during the meeting by visiting www.virtualshareholdermeeting.com/NP2022SM and using the 16-digit control number found on their proxy cards. Neenah recommends that Neenah stockholders log in at least fifteen minutes before the meeting to ensure that they are logged in when the meeting starts. Online check-in will start shortly before the meeting on June 29, 2022.

Approval of the Neenah merger proposal requires the affirmative vote of holders of two-thirds of the outstanding shares of common stock, $0.01 par value per share, of Neenah (which we refer to as “Neenah common stock”), entitled to vote on the Neenah merger proposal. Approval of each of the Neenah compensation proposal and the Neenah adjournment proposal requires the affirmative vote of the holders of a majority in voting power of the shares of Neenah common stock which are present in person (via the Internet) or by proxy at the Neenah special meeting and entitled to vote thereon.

The board of directors of Neenah (which we refer to as the “Neenah board of directors”) has unanimously (i) determined that the merger agreement and the transactions contemplated thereby, including the merger, are advisable, fair to and in the best interests of Neenah and its stockholders, (ii) approved and adopted the merger agreement and the execution, delivery and performance by Neenah of the merger agreement and the transactions contemplated thereby, including the merger, and (iii) recommended that Neenah’s stockholders approve the

merger proposal. The Neenah board of directors unanimously recommends that Neenah stockholders vote “FOR” the Neenah merger proposal, “FOR” the Neenah compensation proposal and “FOR” the Neenah adjournment proposal.

Your vote is very important. SWM and Neenah cannot complete the merger unless Neenah’s stockholders approve the Neenah merger proposal.

Regardless of whether you plan to attend the Neenah special meeting in person (via the Internet), please vote as soon as possible by following the voting procedures described on the proxy card. If you do not vote or if you submit a proxy card on which you indicate that you abstain from voting on the Neenah merger proposal, it will have the same effect as a vote “AGAINST” against the Neenah merger proposal.

Neenah will not transact any business at the Neenah special meeting, except such business as may properly be brought before the Neenah special meeting or any adjournments or postponements thereof by or at the direction of the Neenah board of directors.

The enclosed joint proxy statement/prospectus provides a detailed description of the Neenah special meeting, the merger, the documents related to the merger, including the merger agreement, and other related matters. We urge you to read the joint proxy statement/prospectus, including any documents incorporated in the joint proxy statement/prospectus by reference, and its annexes carefully and in their entirety.

REFERENCES TO ADDITIONAL INFORMATION

This joint proxy statement/prospectus incorporates important business and financial information about SWM and Neenah from documents filed with the U.S. Securities and Exchange Commission (which we refer to as the “SEC”) that are not included in or delivered with this joint proxy statement/prospectus. You can obtain any of the documents filed with or furnished to the SEC by SWM and/or Neenah at no cost from the SEC’s website at http://www.sec.gov. You may also request copies of these documents, including documents incorporated by reference in this joint proxy statement/prospectus, at no cost by contacting the appropriate company at the following address:

You will not be charged for any of these documents that you request. To obtain timely delivery of these documents, you must request them no later than five (5) business days before the date of the applicable special meeting. This means that SWM stockholders requesting documents must do so by June 22, 2022, and Neenah stockholders requesting documents must do so by June 22, 2022.

You should rely only on the information contained in, or incorporated by reference into, this document. No one has been authorized to provide you with information that is different from that contained in, or incorporated by reference into, this document. This document is dated May 20, 2022, and you should assume that the information in this document is accurate only as of such date. You should assume that the information incorporated by reference into this document is accurate as of the date of such incorporated document. Neither the mailing of this document to SWM stockholders or Neenah stockholders, nor the issuance by SWM of shares of SWM common stock in connection with the merger, will create any implication to the contrary.

For more information, please see “Where You Can Find More Information” beginning on page 188.

ABOUT THIS DOCUMENT

SWM has supplied all information contained in or incorporated by reference into this joint proxy statement/prospectus relating to SWM. Neenah has supplied all information contained in or incorporated by reference into this joint proxy statement/prospectus relating to Neenah. SWM and Neenah have both contributed information relating to the merger.

This joint proxy statement/prospectus forms a part of a Registration Statement on Form S-4 (Registration No. 333-264676) filed by SWM with the SEC. It constitutes a prospectus of SWM under Section 5 of the Securities Act of 1933, as amended (which we refer to as the “Securities Act”), and the rules thereunder, with respect to the shares of SWM common stock to be issued to Neenah stockholders in the merger. It also constitutes a proxy statement under Section 14(a) of the Securities Exchange Act of 1934, as amended (which we refer to as the “Exchange Act”) and a notice of meeting and action to be taken with respect to the SWM special meeting at which SWM stockholders will consider and vote on the SWM share issuance proposal and the other proposals described in this joint proxy statement/prospectus.

In addition, this document constitutes a proxy statement under Section 14(a) of the Exchange Act and a notice of meeting and action to be taken with respect to (i) the SWM special meeting at which SWM stockholders will consider and vote on the SWM share issuance proposal and the SWM adjournment proposal and (ii) the Neenah special meeting at which Neenah stockholders will consider and vote on the Neenah merger proposal, the Neenah compensation proposal and the Neenah adjournment proposal, all as described in this joint proxy statement/prospectus.

This document does not constitute an offer to sell, or a solicitation of an offer to buy, any securities, or the solicitation of a proxy, in any jurisdiction in which or from any person to whom it is unlawful to make any such offer or solicitation in such jurisdiction.

TABLE OF CONTENTS

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QUESTIONS AND ANSWERS

The following are some questions that you may have about the merger and the SWM and Neenah special meetings, and brief answers to those questions. We urge you to read carefully the remainder of this joint proxy statement/prospectus because the information in this section does not provide all of the information that might be important to you with respect to the merger, or the SWM and Neenah special meetings. Additional important information is also contained in the documents incorporated by reference into this joint proxy statement/prospectus. Please see “Where You Can Find More Information” beginning on page 188.

To complete the merger, among other things:

SWM is holding a special meeting of SWM stockholders to obtain approval of the SWM share issuance proposal. SWM stockholders will also be asked to approve the proposal to adjourn the SWM special meeting from time to time if determined by the chairperson of the meeting to be necessary or appropriate, including adjournment to permit further solicitation of proxies in favor of the SWM share issuance proposal or to ensure that any supplement or amendment to this joint proxy statement/prospectus is timely provided to SWM stockholders. The approval of the SWM adjournment proposal by the SWM stockholders is not required to complete the merger.

Neenah is holding a special meeting of Neenah stockholders to obtain approval of the Neenah merger proposal. Neenah stockholders will also be asked to (i) approve, on an advisory (non-binding) basis, the compensation that may be paid or become payable to Neenah’s named executive officers that is based on or otherwise relates to the merger, and (ii) approve the proposal to adjourn the Neenah special meeting from time to time, if determined by the chairperson of the meeting to be necessary or appropriate, including adjournment to permit further solicitation of proxies in favor of the Neenah merger proposal or to ensure that any supplement or amendment to this joint proxy statement/prospectus is timely provided to Neenah stockholders. Neither the approval of the Neenah compensation proposal nor the approval of the Neenah adjournment proposal by the Neenah stockholders is required to complete the merger.

This document is also a prospectus that is being delivered to Neenah stockholders because, in connection with the merger, SWM is offering shares of SWM common stock to Neenah stockholders.

This joint proxy statement/prospectus contains important information about the merger agreement, the merger and the other proposals being voted on at the SWM and Neenah special meetings. You should read it carefully and in its entirety. The enclosed materials allow you to have your shares of common stock voted by proxy without attending your meeting. Your vote is important and we encourage you to submit your proxy as soon as possible.

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More information may be found in the section entitled “The Merger —Governance of the Combined Company” beginning on page 117.

The Neenah special meeting will be held virtually via live webcast on the Internet at www.virtualshareholdermeeting.com/NP2022SM, on June 29, 2022, at 9:00 a.m. Eastern Time.

Even if you plan to virtually attend your respective company’s special meeting, SWM and Neenah recommend that you vote your shares in advance (as described under “How can I vote my shares without attending my respective special meeting?” below) so that your vote will be counted if you later decide not to or become unable to attend the applicable special meeting. Shares held in “street name” through a bank, broker or other nominee may be voted in person (via the Internet) by you only if you obtain a signed legal proxy from your broker, bank or other nominee giving you the right to vote the shares.

2

At the Neenah special meeting, Neenah stockholders will be asked to consider and vote on the following proposals:

To complete the merger, among other things, SWM stockholders must approve the SWM share issuance proposal, and Neenah stockholders must approve the Neenah merger proposal. None of the approvals of the SWM adjournment proposal, the Neenah compensation proposal or the Neenah adjournment proposal are conditions to the obligations of SWM or Neenah to complete the merger, and the merger may be completed even if approval of one or more of those proposals is not obtained.

3

See “The Merger—Interests of Certain SWM Directors and Executive Officers in the Merger,” “The Merger—Interests of Certain Neenah Directors and Executive Officers in the Merger” and “The Merger—Governance of the Combined Company” beginning on pages 107, 111 and 117, respectively.

See “The Merger Agreement—Treatment of Neenah Equity Awards” beginning on page 129.

4

See “The Merger Agreement—Treatment of Neenah Equity Awards” beginning on page 129.

See “The Merger Agreement—Treatment of Neenah Equity Awards” beginning on page 129.

5

See “The Merger Agreement—Treatment of Neenah Equity Awards” beginning on page 129.

In considering the recommendations of the SWM board of directors, SWM stockholders should be aware that SWM directors and executive officers may have interests in the merger that are different from, or in addition to, the interests of SWM stockholders generally. For a more complete description of these interests, see “The Merger—Interests of SWM’s Directors and Executive Officers in the Merger” beginning on page 107.

In considering the recommendations of the Neenah board of directors, Neenah stockholders should be aware that Neenah directors and executive officers may have interests in the merger that are different from, or in addition to, the interests of Neenah stockholders generally. For a more complete description of these interests, see “The Merger—Interests of Neenah’s Directors and Executive Officers in the Merger” beginning on page 111.

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Each SWM stockholder is entitled to cast one (1) vote on each matter properly brought before the SWM special meeting for each share of SWM common stock that such holder owned of record as of the record date. As of the close of business on the record date for the SWM special meeting, there were                 outstanding shares of SWM common stock. See below and “The SWM Special Meeting—Voting of Proxies” beginning on page 49 for instructions on how to vote your shares without attending the SWM special meeting.

Each Neenah stockholder is entitled to cast one (1) vote on each matter properly brought before the Neenah special meeting for each share of Neenah common stock that such holder owned of record as of the record date. As of the close of business on the record date for the Neenah special meeting, there were                  outstanding shares of Neenah common stock. See below and “The Neenah Special Meeting—Voting of Proxies” beginning on page 56 for instructions on how to vote your shares without attending the Neenah special meeting.

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If you are an SWM stockholder entitled to vote at the SWM special meeting and you do not attend the SWM special meeting in person (via the Internet), return a proxy, or provide voting instructions to your brokerage firm, your shares will not be voted and will not be treated as present for purposes of establishing a quorum, and assuming a quorum is present, this failure to vote will have no effect on the SWM share issuance proposal.

SWM Proposal 2: SWM adjournment proposal. Approval of the SWM adjournment proposal requires the affirmative vote of a majority of the shares of SWM common stock present in person (via the Internet) or represented by proxy at the SWM special meeting and entitled to vote thereon. If you attend the SWM special meeting in person (via the Internet) and do not vote, or if you submit a proxy card on which you indicate that you abstain from voting, this will have the effect of a vote “AGAINST” the SWM adjournment proposal.

If you are an SWM stockholder entitled to vote at the SWM special meeting and you do not attend the SWM special meeting in person (via the Internet) return a proxy, or provide voting instructions to your brokerage firm, your shares will not be voted and will not be treated as present for purposes of establishing a quorum, and assuming a quorum is present, this failure to vote will have no effect on the SWM adjournment proposal.

Because it is expected that all proposals to be voted on at the SWM special meeting will be “non-routine” matters, it is unlikely that there will be any broker non-votes at the SWM special meeting.

If you are a Neenah stockholder entitled to vote at the Neenah special meeting and you do not attend the Neenah special meeting in person (via the Internet), return a proxy, or provide voting instructions to your brokerage firm, your shares will not be voted and will not be treated as present for purposes of establishing a quorum, and this failure to vote will have the effect of a vote “AGAINST” the Neenah merger proposal.

Neenah Proposal 2: Neenah compensation proposal. Approval of the Neenah compensation proposal requires the affirmative vote of the holders of a majority in voting power of the shares of Neenah common stock which are present in person (via the Internet) or represented by proxy at the Neenah special meeting and entitled to vote on the Neenah compensation proposal; however, such vote is non-binding and advisory only. If you attend the Neenah special meeting in person (via the Internet) and do not vote, or if you submit a proxy card on which you indicate that you abstain from voting, this will have the effect of a vote “AGAINST” the Neenah compensation proposal.

If you are a Neenah stockholder entitled to vote at the Neenah special meeting and you do not attend the Neenah special meeting in person (via the Internet), return a proxy or provide voting instructions to your brokerage firm, your shares will not be voted and will not be treated as present for purposes of establishing a quorum, and this failure to vote will have no effect on the Neenah compensation proposal.

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Neenah Proposal 3: Neenah adjournment proposal. Approval of the Neenah adjournment proposal requires the affirmative vote of the holders of a majority in voting power of the shares of Neenah common stock which are present in person (via the Internet) or represented by proxy at the Neenah special meeting and entitled to vote on the Neenah adjournment proposal. If you attend the Neenah special meeting in person (via the Internet) and do not vote, or if you submit a proxy card on which you indicate that you abstain from voting, this will have the effect of a vote “AGAINST” the Neenah adjournment proposal.

If you are a Neenah stockholder entitled to vote at the Neenah special meeting and you do not attend the Neenah special meeting in person (via the Internet), return a proxy or provide voting instructions to your brokerage firm, your shares will not be voted and will not be treated as present for purposes of establishing a quorum, and assuming a quorum is present, this will have no effect on the Neenah adjournment proposal.

Because it is expected that all proposals to be voted on at the Neenah special meeting will be “non-routine” matters, it is unlikely that there will be any broker non-votes at the Neenah special meeting.

Shares in “street name.” Shares held in “street name” through a bank, broker or other nominee may be voted in person (via the Internet) by you only if you obtain a signed legal proxy from your broker, bank or

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other nominee giving you the right to vote the shares. If you choose to vote your shares in person (via the Internet) at the SWM special meeting or the Neenah special meeting, as applicable, please follow the voting instructions provided by your broker, bank or other nominee.

Even if you plan to attend the SWM special meeting or the Neenah special meeting in person (via the Internet), as applicable, SWM and Neenah recommend that you vote your shares in advance as described below so that your vote will be counted if you later decide not to or become unable to attend the respective special meeting.

Additional information on attending the special meetings can be found under the section entitled “The SWM Special Meeting” on page 48 and under the section entitled “The Neenah Special Meeting” on page 54.

Additional information on voting procedures can be found under the section entitled “The SWM Special Meeting” on page 48 and under the section entitled “The Neenah Special Meeting” on page 54.

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If your shares are held by a broker, bank or other nominee, you should contact your broker, bank or other nominee to change your vote.

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Record holders. For shares held directly, please complete, sign, date and return each proxy card by mail (or cast your vote by telephone or Internet as provided on each proxy card) or otherwise follow the voting instructions provided in this joint proxy statement/prospectus to ensure that all of your shares of SWM common stock or Neenah common stock are voted.

Shares in “street name.” For shares held in “street name” through a broker, bank or other nominee, you should follow the procedures provided by your broker, bank or other nominee to vote your shares.

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

Certain of the matters discussed in this joint proxy statement/prospectus that are not statements of historical fact constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements, which are based on current expectations, estimates and projections about the industry and markets in which SWM and Neenah operate and beliefs of and assumptions made by SWM management and Neenah management, involve uncertainties that could significantly affect the financial condition, results of operations, business plans and future performance of SWM, Neenah or the combined company.

Words such as “believes,” “anticipates,” “expects,” “assumes,” “outlook,” “intends,” “targeted,” “estimates,” “forecasts,” “projects,” “plans,” “may,” “could,” “should,” “would” and similar expressions are intended to identify forward-looking statements but are not the exclusive means of identifying these statements. Such forward-looking statements include, but are not limited to, statements about the strategic rationale and financial benefits of the transaction, including expected future financial and operating results and the combined company’s plans, objectives, expectations and intentions. All statements that address operating performance, events or developments that we expect or anticipate will occur in the future — including statements relating to projections of revenue, income or loss, earnings or loss per share, the payment or nonpayment of dividends, capital structure and other financial items; statements of plans and objectives of SWM or Neenah or their respective management or boards of directors, including those relating to products or services; and statements of future economic performance — are forward-looking statements. These statements are not guarantees of future performance and involve certain risks, uncertainties and assumptions that are difficult to predict. Although we believe the expectations reflected in any forward-looking statements are based on reasonable assumptions, we can give no assurance that our expectations will be attained, and therefore actual outcomes and results may differ materially from what is expressed or forecasted in such forward-looking statements.

In addition to factors relating to the merger discussed under the caption “Risk Factors” beginning on page 38 and the factors previously disclosed in SWM’s and Neenah’s reports filed with the SEC, the following factors, among others, could cause actual results to differ materially from forward-looking statements or historical performance:

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Any forward-looking statements speak only as of the date of this communication or as of the date they were made, and neither SWM nor Neenah undertakes any obligation to update forward-looking statements. For a more detailed discussion of these factors, also see the information under the captions “Risk Factors” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in SWM’s and Neenah’s most recent annual reports on Form 10-K for the year ended December 31, 2021, and any material updates to these factors contained in any of SWM’s and Neenah’s future filings with the SEC.

As for the forward-looking statements that relate to future financial results and other projections, actual results will be different due to the inherent uncertainties of estimates, forecasts and projections and may be better or

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worse than projected and such differences could be material. Given these uncertainties, you should not place any reliance on these forward-looking statements. Annualized, pro forma, projected and estimated numbers are used for illustrative purpose only, are not forecasts and may not reflect actual results.

For additional information about factors that could cause actual results to differ materially from those described in the forward-looking statements, please see the reports that SWM and Neenah have filed with the SEC as described under “Where You Can Find More Information” beginning on page 188.

We expressly qualify in their entirety all forward-looking statements attributable to either of us or any person acting on our behalf by the cautionary statements contained or referred to in this joint proxy statement/prospectus.

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RISK FACTORS

In addition to the other information contained in or incorporated by reference into this joint proxy statement/prospectus, including the matters addressed under the caption “Cautionary Statement Regarding Forward-Looking Statements” beginning on page 35, you should carefully consider the following risk factors in deciding whether to vote for the approval of the merger agreement and the transactions contemplated thereby, including the merger and including the issuance of shares of SWM common stock in the merger.

Because the market price of SWM common stock may fluctuate, Neenah stockholders cannot be sure of the market value of the merger consideration they will receive.

In the merger, each share of Neenah common stock issued and outstanding immediately prior to the effective time (other than certain shares held by SWM or Neenah) will be converted into 1.358 shares of SWM common stock (plus cash in lieu of fractional shares). This exchange ratio is fixed and will not be adjusted to reflect any changes in the market price of either SWM common stock or Neenah common stock. Changes in the price of SWM common stock prior to the merger will affect the value that Neenah stockholders will receive in the merger. Neither SWM nor Neenah is permitted to terminate the merger agreement solely because of any increase or decrease in the market price of SWM common stock or Neenah common stock.

The prices of Neenah common stock and SWM common stock at the closing of the merger may vary from their prices on March 25, 2022, the last trading day before public announcement of the merger. Stock price changes may result from a variety of factors that are beyond the control of Neenah and SWM, including market reaction to the announcement of the merger, general market and economic conditions, changes in their respective businesses, operations, results and prospects and legal and regulatory considerations. Therefore, at the time of the Neenah special meeting, Neenah stockholders will not know the market value of the consideration to be received at the effective time. Holders of Neenah common stock should obtain current market quotations for SWM common stock and Neenah common stock.

The market price of SWM common stock after the merger may be affected by factors different from factors that have historically affected and are currently affecting SWM common stock or Neenah common stock.

Upon completion of the merger and the transactions contemplated by the merger agreement, Neenah stockholders will become SWM stockholders, and the combined company will operate an expanded business with a different mix of products, operations and associated risks and liabilities. Accordingly, the results of operations of the combined company and the market price of SWM common stock after the completion of the merger may be affected by factors different from those that have historically affected and are currently affecting the independent results of operations of each of SWM and Neenah and the respective market prices of SWM common stock and Neenah common stock.

Additionally, SWM stockholders and Neenah stockholders may not wish to continue to invest in the combined company, or may wish to dispose of some or all of their SWM common stock. If, before or after the effective time, large amounts of SWM common stock are sold, the market price of SWM common stock could decline.

For a discussion of the businesses of SWM and Neenah and certain factors to consider in connection with those businesses, see the documents incorporated by reference in this joint proxy statement/prospectus and referred to under “Where You Can Find More Information” beginning on page 188.

The dilution caused by the issuance of shares of SWM common stock in connection with the merger may adversely affect the market price of SWM common stock.

In connection with the payment of the merger consideration, based on the number of shares of Neenah stock outstanding as of May 20, 2022, SWM expects to issue approximately                million shares of SWM

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common stock to Neenah stockholders. The dilution caused by the issuance of these new shares of SWM common stock may result in fluctuations in the market price of SWM common stock, including a stock price decrease.

Holders of SWM common stock and Neenah common stock will have a diluted ownership percentage and voting interest in the combined company after the merger and will exercise less influence over management.

Holders of SWM common stock and Neenah common stock currently have the right to vote in the election of the board of directors and on other matters affecting SWM and Neenah, respectively. In the merger, each holder of Neenah common stock who receives shares of SWM common stock will become a holder of common stock of the combined company, with a percentage ownership of the combined company that is smaller than the stockholder’s percentage ownership of, and voting interests in, Neenah immediately prior to the merger. We estimate that, upon completion of the merger, Neenah stockholders as of immediately prior to the merger will collectively own approximately 42% of the outstanding shares of the combined company immediately after the merger, and SWM stockholders as of immediately prior to the merger will collectively own approximately 58% of the outstanding shares of the combined company immediately after the merger (in each case, on a fully diluted basis and without regard to the fact that immediately prior to the merger, certain stockholders may own both SWM common stock and Neenah common stock). In addition, the board of directors of the combined company will be composed of nine (9) directors, of which five (5) will be designated by SWM and four (4) will be designated by Neenah.

Accordingly, Neenah stockholders, as a group, will have less than a majority of the ownership and voting power of the combined company, and therefore will be able to exercise less collective influence on the management and policies of the combined company than they currently are able to exercise on the management and policies of Neenah, and SWM stockholders may have less influence on the management and policies of the combined company than they now have on the management and policies of SWM.

The shares of SWM common stock to be received by Neenah stockholders as a result of the merger will have different rights from the shares of Neenah common stock.

In the merger, Neenah stockholders will become SWM stockholders, and their rights as stockholders will be governed by the certificate of incorporation and bylaws of the combined company. The rights associated with SWM common stock are different from the rights associated with Neenah common stock. See the section entitled “Comparison of the Rights of SWM Stockholders’ and Neenah Stockholders’” beginning on page 171 for a discussion of the different rights associated with SWM common stock.

Certain of SWM’s and Neenah’s directors and executive officers may have interests in the merger that may differ from the interests of SWM stockholders and Neenah stockholders.

SWM stockholders and Neenah stockholders should be aware that some of the SWM and Neenah directors and executive officers may have interests in the merger and have arrangements that are different from, or in addition to, those of SWM stockholders and Neenah stockholders generally. These interests and arrangements may create potential conflicts of interest. Both the SWM board of directors and Neenah board of directors were aware of these respective interests and considered these interests, among other matters, when making their respective decisions to approve the merger agreement, and in recommending that stockholders vote to approve the merger. For a more complete description of these interests, please see the sections entitled “The Merger—Interests of SWM’s Directors and Executive Officers in the Merger” beginning on page 107 and “The Merger—Interests of Neenah’s Directors and Executive Officers in the Merger” beginning on page 111.

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The fairness opinions obtained by the SWM board of directors and the Neenah board of directors from their respective financial advisors will not reflect changes, circumstances, developments or events that may have occurred or may occur after the date of the opinions.

J.P. Morgan, SWM’s financial advisor in connection with the merger, delivered to the SWM board of directors a written opinion, dated March 27, 2022, that, as of such date and based upon and subject to the various factors and assumptions set forth in its opinion, the exchange ratio in the proposed merger was fair, from a financial point of view, to SWM. Perella Weinberg, Neenah’s financial advisor in connection with the merger, delivered a written opinion, dated March 27, 2022, to the Neenah board of directors to the effect that, as of the date thereof, and based upon and subject to the various assumptions made, procedures followed, matters considered and qualifications and limitations set forth in such written opinion, the exchange ratio provided for pursuant to the merger agreement was fair, from a financial point of view, to the Neenah stockholders (other than SWM and its affiliates).

The SWM board of directors and the Neenah board of directors have not obtained updated fairness opinions as of the date of this joint proxy statement/prospectus from their respective financial advisors and do not expect to receive updated fairness opinions prior to the completion of the merger.

The fairness opinions do not reflect changes, circumstances, developments or events that may have occurred or may occur after the date of the opinions, including changes in the operations and prospects of SWM and Neenah or their respective operating companies, regulatory or legal changes, general market and economic conditions and other factors that may be beyond the control of SWM and Neenah and on which the fairness opinions were based and that may alter the value of SWM and Neenah or the prices of shares of SWM common stock or Neenah common stock at the effective time. The implied value of the stock consideration has fluctuated since, and could be materially different from its value as of the date of the opinions, and the opinions do not address the prices at which shares of SWM common stock or Neenah common stock may trade since the dates of the opinions. The opinions do not speak as of the time the merger will be completed or as of any date other than the dates of such opinions. The SWM board of directors and the Neenah board of directors do not anticipate asking their respective financial advisors to update their respective opinions, and none of the respective financial advisors has an obligation or responsibility to update, revise or reaffirm its respective opinion based on circumstances, developments or events that may have occurred or may occur after the date of such opinion. The opinions of the financial advisors to the SWM board of directors and the Neenah board of directors are attached as Annex B and Annex C, respectively, to this joint proxy statement/prospectus and are incorporated by reference herein.

SWM and Neenah are expected to incur substantial costs related to the merger and the integration of the businesses.

SWM and Neenah have incurred and expect to incur a number of non-recurring costs associated with the merger. These costs include financial advisory, legal, accounting, consulting and other advisory fees, severance/employee benefit-related costs, financing-related fees and costs, public company filing fees and other regulatory fees, printing costs and other related costs. Many of these costs are payable by either SWM or Neenah regardless of whether or not the merger is completed.

The combined company will also incur substantial integration costs in connection with the merger. There are a large number of processes, policies, procedures, operations, technologies and systems that must be integrated in connection with the merger and the integration of the two companies’ businesses, including purchasing, accounting and finance, sales, payroll, pricing and benefits.

While both SWM and Neenah have assumed that certain expenses would be incurred in connection with the merger and the integration of the businesses, there are many factors beyond their control that could affect the total amount or the timing of the integration expenses. Moreover, many of the costs that will be incurred are, by

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their nature, difficult to estimate accurately. Although SWM and Neenah expect that the elimination of duplicative costs and the realization of other economies of scale-related efficiencies related to the integration of the businesses may offset incremental merger-related and integration costs over time, any net benefit may not be achieved in the near term or at all. These integration costs may result in the combined company taking significant charges against earnings following the completion of the merger, and the amount and timing of such charges are uncertain at present.

Combining SWM and Neenah may be more difficult, costly or time consuming than expected, and SWM and Neenah may fail to realize some or all of the anticipated benefits of the merger.

The success of the merger will depend, in part, on the ability to realize the anticipated cost savings, operational synergies and other perceived benefits from combining the businesses of SWM and Neenah. To realize the cost savings, operational synergies and other perceived benefits from the merger, SWM and Neenah must successfully integrate and combine their businesses in a manner that permits those benefits to be realized. If SWM and Neenah are not able to achieve these objectives, the anticipated benefits of the merger may not be realized fully or at all, or may take longer to realize than expected. For example, the actual cost savings, operational synergies and other perceived benefits of the merger could be less than anticipated or take longer to realize than anticipated for a variety of reasons, including those set forth in these Risk Factors.

SWM and Neenah have operated and, until the completion of the merger, must continue to operate, independently. It is possible that the integration process could result in the loss of key employees, the disruption of each company’s ongoing businesses or inconsistencies in standards, controls, procedures and policies that adversely affect the companies’ ability to maintain relationships with employees, customers, suppliers or other business associates and constituencies or to achieve the anticipated benefits and cost savings of the merger. Integration efforts between the two companies may also divert management attention and resources. These integration matters could have an adverse effect on each of SWM and Neenah during this transition period and for an undetermined period after completion of the merger on the combined company.

The merger may result in a loss of customers, distributors, suppliers, vendors, landlords, joint venture partners and other business partners and may result in the termination of existing contracts.

Following the merger, some of the customers, distributors, suppliers, vendors, landlords, joint venture partners and other business partners of SWM or Neenah may terminate or scale back their current or prospective business relationships with the combined company. Some customers may not wish to source a larger percentage of their needs from a single company or may feel that the combined company is too closely allied with one of their competitors. In addition, SWM and Neenah have contracts with customers, distributors, suppliers, vendors, landlords, joint venture partners and other business partners that may require SWM or Neenah to obtain consents from these other parties in connection with the merger, which may not be obtained on favorable terms or at all. If relationships with customers, distributors, suppliers, vendors, landlords, joint venture partners and other business partners are adversely affected by the merger, or if the combined company, following the merger, loses the benefits of the contracts of SWM or Neenah, the combined company’s business and financial performance could suffer.

The combined company may be unable to retain SWM or Neenah personnel successfully prior to the effective time or after the merger is completed.

The success of the merger will depend in part on the combined company’s ability to retain the talents and dedication of key employees currently employed by SWM and Neenah. It is possible that these employees may decide not to remain with SWM or Neenah, as applicable, prior to the effective time or with the combined company after the merger is consummated. If SWM and Neenah are unable to retain key employees, including management, who are critical to the successful integration and future operations of the companies, SWM and Neenah could face disruptions in their operations, loss of existing customers, loss of key information, expertise

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or know-how and unanticipated additional recruitment costs. In addition, if key employees terminate their employment, the combined company’s business activities may be adversely affected, and management’s attention may be diverted from successfully integrating SWM and Neenah to hiring suitable replacements, all of which may cause the combined company’s business to suffer. In addition, SWM and Neenah may not be able to locate or retain suitable replacements for any key employees who leave either company. For more information, see the section entitled “The Merger—Governance of the Combined Company” beginning on page 117.

The combined company’s future results may suffer if it does not effectively manage its expanded operations following the merger.

Following the merger, the size of the business of the combined company will increase significantly beyond the current size of either SWM’s or Neenah’s business. The combined company’s future success will depend, in part, upon its ability to manage this expanded business, which will pose substantial challenges for management, including challenges related to the management and monitoring of new operations and associated increased costs and complexity. There can be no assurances that the combined company will be successful or that it will realize the expected operating efficiencies, cost savings, revenue enhancements or other benefits currently anticipated from the merger.

The merger agreement subjects SWM and Neenah to restrictions on their respective business activities prior to the effective time.

The merger agreement subjects SWM and Neenah to restrictions on their respective business activities prior to the effective time. The merger agreement obligates each of SWM and Neenah to, and to cause each of its subsidiaries to, subject to specified exceptions, conduct its business in the ordinary course in all material respects and use reasonable best efforts to maintain and preserve intact its business organization, employees and advantageous business relationships. These restrictions could prevent SWM and Neenah from pursuing certain business opportunities that arise prior to the effective time and are outside the ordinary course of business. See the section entitled “The Merger Agreement—Covenants and Agreements—Conduct of Businesses Prior to the Completion of the Merger” beginning on page 134 for a description of the restrictive covenants applicable to SWM and Neenah.

The merger agreement limits SWM’s and Neenah’s respective ability to pursue alternatives to the merger and may discourage other companies from trying to acquire SWM or Neenah.

The merger agreement contains “no shop” covenants that restrict each of SWM’s and Neenah’s ability to, directly or indirectly, initiate, solicit, knowingly encourage or knowingly facilitate any inquiries or proposals with respect to any acquisition proposal, engage or participate in any negotiations with any person concerning any acquisition proposal, provide any confidential or nonpublic information or data to, or have or participate in any discussions with, any person relating to any acquisition proposal, subject to certain exceptions, or, unless the merger agreement has been terminated in accordance with its terms, approve or enter into any term sheet, letter of intent, commitment, memorandum of understanding, agreement in principle, acquisition agreement, merger agreement or other agreement in connection with or relating to any acquisition proposal.

The merger agreement further provides that, during the 12-month period following the termination of the merger agreement under specified circumstances, including the entry into a definitive agreement or consummation of a transaction with respect to an alternative acquisition proposal, SWM or Neenah may be required to pay to the other party a cash termination fee equal to $24 million. See the section entitled “The Merger Agreement—Termination Fee” beginning on page 150.

These provisions could discourage a potential third-party acquirer that might have an interest in acquiring all or a significant portion of SWM or Neenah from considering or proposing that acquisition.

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The merger agreement may be terminated in accordance with its terms and the merger may not be completed, which could negatively affect SWM or Neenah, and, in certain circumstances, result in the requirement that SWM or Neenah pay a termination fee.

If the merger agreement is terminated and the merger is not completed, including as a result of either SWM stockholders failing to approve the SWM share issuance proposal or Neenah stockholders failing to approve the Neenah merger proposal, there may be various adverse consequences, and SWM and Neenah may experience negative reactions from the financial markets and from their respective customers and employees. For example, SWM’s or Neenah’s businesses may have been affected adversely by the failure to pursue other beneficial opportunities due to the focus of management on the merger, without realizing any of the anticipated benefits of completing the merger.

Additionally, each of SWM and Neenah has incurred and will incur substantial costs in connection with the negotiation and completion of the transactions contemplated by the merger agreement, as well as the costs of filing, printing and mailing this joint proxy statement/prospectus, and all filing and other fees paid to the SEC in connection with the merger. If the merger is not completed, SWM and Neenah would have to recognize these as expenses without realizing the expected benefits of the merger.

Moreover, if the merger agreement is terminated, the market price of SWM common stock or Neenah common stock could decline to the extent that the current market prices reflect a market assumption that the merger will be completed. If the merger agreement is terminated under certain circumstances, either SWM or Neenah may be required to pay a termination fee of $24 million to the other party, which, if payable at all, may not sufficiently compensate the party receiving such termination fee for the adverse effects arising out of such termination.

See the sections entitled “The Merger Agreement—Termination of the Merger Agreement,” “The Merger Agreement—Effect of Termination” and “The Merger Agreement—Termination Fee” beginning on pages 148, 149 and 150, respectively.

SWM will incur indebtedness in connection with the merger, which could adversely affect SWM and the combined company, including by decreasing the business flexibility of the combined company.

Consummation of the merger is not conditioned on SWM’s ability to obtain financing. SWM plans to use debt financing and cash on hand to fund certain fees and costs relating to the merger and to refinance certain of its existing indebtedness and certain existing indebtedness of Neenah. Such debt financing could take any of several forms or any combination of them, including but not limited to the following: (i) SWM may borrow up to $650.0 million under the delayed draw facility; (ii) SWM may borrow under the revolving credit facility; (iii) SWM may borrow under the bridge facility; and (iv) SWM may issue senior notes in the public and/or private capital markets. See the section entitled “The Merger—Description of Financing” beginning on page 120.

SWM’s increased level of debt and the covenants to which SWM will have agreed in connection with this debt financing could have negative consequences on SWM and the combined company, including, among other things, (i) requiring SWM, and the combined company, to dedicate a larger portion of cash flow from operations to servicing and repayment of the debt, (ii) reducing funds available for strategic initiatives and opportunities, working capital and other general corporate needs and (iii) limiting SWM’s, and the combined company’s, ability to incur certain kinds or amounts of additional indebtedness, which could restrict its flexibility to react to changes in its business, its industry and economic conditions.

The unaudited pro forma condensed combined financial information included in this joint proxy statement/prospectus is preliminary, and the actual financial condition and results of operations of the combined company following the merger may differ materially.

The unaudited pro forma condensed combined financial information in this joint proxy statement/prospectus is presented for illustrative purposes only and is not necessarily indicative of what the combined company’s actual

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financial condition or results of operations would have been had the merger been completed on the dates indicated. The unaudited pro forma condensed combined financial information reflects adjustments, which are based upon preliminary estimates, to reflect the Neenah identifiable assets to be acquired and liabilities to be assumed at fair value and the resulting goodwill. The fair value estimates reflected in this joint proxy statement/prospectus are preliminary, and final amounts will be based upon the actual consideration and the fair value of the assets and liabilities of Neenah as of the acquisition date for accounting purposes. Accordingly, the final acquisition accounting adjustments may differ materially from the pro forma adjustments reflected in this joint proxy statement/prospectus. For more information, see the section entitled “Unaudited Pro Forma Condensed Combined Financial Information” beginning on page 152.

Regulatory approvals may not be received, may take longer than expected, and regulatory authorities may impose conditions or requirements that are not presently anticipated or that could have an adverse effect on the combined company following the merger.

Before the merger can be completed, certain approvals, consents, clearances, orders and authorizations must be obtained from various antitrust and regulatory authorities in the United States and in foreign jurisdictions. The governmental entities from which these approvals are required may refuse to approve the merger or impose conditions or requirements for the completion of the merger. Any conditions or requirements imposed could have the effect of delaying or preventing completion of the merger. Even if the requisite regulatory approvals are granted, the relevant regulatory authorities may impose conditions, limitations, obligations or costs, or place restrictions on the conduct of the combined company’s business or require changes to the terms of the transactions contemplated by the merger agreement.

There can be no assurance that regulators will not impose any such conditions, limitations, obligations or restrictions and that such conditions, limitations, obligations or restrictions will not have the effect of delaying the completion of any of the transactions contemplated by the merger agreement, imposing additional material costs on or materially limiting the revenues of the combined company following the merger or otherwise reduce the anticipated benefits of the merger if the merger were consummated successfully within the expected timeframe. For more information, see the section entitled “The Merger—Regulatory Approvals” beginning on page 119.

SWM stockholders and Neenah stockholders will not have appraisal rights or dissenters’ rights in the merger.

Appraisal rights (also known as dissenters’ rights) are statutory rights that, if applicable under relevant law, enable stockholders to dissent from an extraordinary transaction, such as a merger, and to demand that the corporation pay the fair value for their shares as determined by a court in a judicial proceeding instead of receiving the consideration offered to stockholders in connection with the extraordinary transaction.

Under Section 262 of the DGCL, stockholders do not have appraisal rights if the shares of stock they hold, as of the record date for determination of stockholders entitled to receive notice of the meeting of stockholders to act upon a merger, are either (i) listed on a national securities exchange or (ii) held of record by more than 2,000 stockholders, unless the stockholders receive in exchange for their shares anything other than (a) shares of stock of the surviving corporation, (b) shares of stock of any other corporation that at the effective time of the merger are listed on a national securities exchange or held by more than 2,000 stockholders of record, (c) cash in lieu of fractional shares or (d) any combination of the foregoing.

If the merger is completed, SWM stockholders will not receive any consideration and their shares of SWM common stock will remain outstanding and constitute shares of stock of the combined company. As a result, SWM stockholders are not entitled to appraisal rights in connection with the merger. Neenah common stock is listed on the NYSE, and because Neenah stockholders will receive shares of SWM common stock in the merger, which is also listed on the NYSE, Neenah stockholders are not entitled to appraisal rights in connection with the merger.

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Stockholder litigation could prevent or delay the closing of the merger or otherwise negatively affect the business and operations of SWM or Neenah.

SWM and Neenah may incur costs in connection with the defense or settlement of the lawsuit related to the proposed merger that has been filed, as of the date of this joint proxy statement/ prospectus, by a purported Neenah stockholder, or the defense or settlement of any further stockholder lawsuits that may be filed in connection with the merger. Such litigation could have an adverse effect on the financial condition, results of operations and cash flows of SWM and Neenah and could prevent or delay the consummation of the merger. For more information, see “The Merger—Litigation Related to the Merger” beginning on page 127.

The COVID-19 pandemic may delay and adversely affect the completion of the merger.

The COVID-19 pandemic has created economic and financial disruptions that have adversely affected, and may continue to adversely affect, the business, financial condition, liquidity, capital and results of operations of SWM and Neenah. Even as efforts to contain the pandemic, including vaccinations, have made progress and some restrictions have relaxed, the impact of new variants that may emerge cannot be predicted at this time, and could depend on numerous factors, including the availability of vaccines in different parts of the world, vaccination rates among the population, the effectiveness of COVID-19 vaccines against such variants and the response by governmental bodies to reinstate restrictive measures or adopt additional requirements or restrictive measures. If the effects of the COVID-19 pandemic cause a continued or extended decline in the economic environment and the financial results of SWM or Neenah, or the business operations of SWM or Neenah are further disrupted as a result of the COVID-19 pandemic, efforts to complete the merger and integrate the businesses of SWM and Neenah may also be delayed and adversely affected.

Risks Relating to SWM’s Business

You should read and consider risk factors specific to SWM’s business that will also affect the combined company after the merger. These risks are described in the sections entitled “Risk Factors” in SWM’s Annual Report on Form 10-K for the year ended December 31, 2021, and in other documents incorporated by reference into this joint proxy statement/prospectus. Please see the section entitled “Where You Can Find More Information” beginning on page 188 for the location of information incorporated by reference into this joint proxy statement/prospectus.

Risks Relating to Neenah’s Business

You should read and consider risk factors specific to Neenah’s business that will also affect the combined company after the merger. These risks are described in the sections entitled “Risk Factors” in Neenah’s Annual Report on Form 10-K for the year ended December 31, 2021, and in other documents incorporated by reference into this joint proxy statement/prospectus. Please see the section entitled “Where You Can Find More Information” beginning on page 188 for the location of information incorporated by reference into this joint proxy statement/prospectus.

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INFORMATION ABOUT THE COMPANIES

SWM

Schweitzer-Mauduit International, Inc.

100 North Point Center East, Suite 600

Alpharetta, Georgia 30022

1-800-514-0186

Schweitzer-Mauduit International, Inc. is a Delaware corporation headquartered in Alpharetta, Georgia.

SWM is a leading global performance materials company, focused on finding ways to improve everyday life by bringing best-in-class innovation, design, and manufacturing solutions to its customers. SWM’s highly engineered films, adhesive tapes, foams, nets, nonwovens, and papers are designed and manufactured using resins, polymers, and natural fibers for a variety of industries and specialty applications. SWM and its subsidiaries manufacture on four continents, conduct business in over 90 countries and employ approximately 5,000 people worldwide.

SWM common stock is traded on the NYSE under the symbol “SWM.”

Additional information about SWM and its subsidiaries is included in documents incorporated by reference in

this joint proxy statement/prospectus. Please see “Where You Can Find More Information” beginning on page 188.

Neenah

Neenah, Inc.

3460 Preston Ridge Road, Suite 600

Alpharetta, Georgia 30005

(678) 566-6500

Neenah, Inc. is a Delaware corporation headquartered in Alpharetta, Georgia. Neenah is a leading global manufacturer of specialty materials, focused on growing in filtration media, specialty coatings, engineered materials and imaging and packaging. Neenah’s materials are in various products used every day, such as transportation and water filters, premium packaging of spirits, technology and beauty products, industrial labels, tapes and abrasives, and digital printing for high-end apparel. Neenah and its subsidiaries manufacture in North America and Europe, conduct business in over 90 countries and employ approximately 2,500 people worldwide.

Neenah’s common stock is traded on the NYSE under the symbol “NP.”

Additional information about Neenah and its subsidiaries is included in documents incorporated by reference in this joint proxy statement/prospectus. Please see “Where You Can Find More Information” beginning on page 188.

Merger Sub

Samurai Warrior Merger Sub, Inc.

c/o Schweitzer-Mauduit International, Inc.

100 North Point Center East, Suite 600

Alpharetta, Georgia 30022

1-800-514-0186

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Samurai Warrior Merger Sub, Inc., a Delaware corporation, is a wholly owned subsidiary of SWM. Merger Sub is newly formed, and was organized for the purpose of entering into the merger agreement and effecting the merger. Merger Sub has engaged in no business activities to date and it has no material assets or liabilities of any kind, other than those incident to its formation and those incurred in connection with the merger.

The Combined Company

Effective as of the effective time, the combined company will be headquartered in Alpharetta, Georgia. SWM will change the name and the NYSE ticker symbol of the combined company to such new name and ticker symbol as mutually agreed upon by SWM and Neenah, which change may occur as of or after the effective time.

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THE SWM SPECIAL MEETING

Date, Time and Place of Meeting

The SWM special meeting will be held virtually via live webcast on the Internet at www.cesonlineservices.com/swm22_vm, on June 29, 2022, at 8:00 a.m. Eastern Time.

Matters to Be Considered

At the SWM special meeting, SWM stockholders will be asked to consider and vote upon the following matters:

Recommendation of the SWM Board of Directors

The SWM board of directors has determined that the merger is advisable and in the best interests of SWM and its stockholders and has unanimously adopted the merger agreement. The SWM board of directors unanimously recommends that SWM stockholders vote “FOR” the SWM share issuance proposal and “FOR” the SWM adjournment proposal. See “The Merger—SWM’s Reasons for the Merger; Recommendation of SWM’s Board of Directors” beginning on page 80 for a more detailed discussion of the SWM board of directors’ recommendation.

SWM Record Date and Quorum

The SWM board of directors has fixed the close of business on May 20, 2022, as the record date for determining the SWM stockholders entitled to receive notice of and to vote at the SWM special meeting and any adjournment or postponement thereof.

As of the SWM record date, there were                  shares of SWM common stock outstanding and entitled to vote at the SWM special meeting held by approximately                  holders of record. Each share of SWM common stock entitles the holder to one vote at the SWM special meeting on each proposal to be considered at the SWM special meeting.

The presence at the SWM special meeting, in person (via the Internet) or by proxy, of holders of a majority of the voting power of the SWM common stock issued and outstanding and entitled to vote will constitute a quorum for the transaction of business. All shares of SWM common stock present in person (via the Internet) or represented by proxy, including abstentions, will be treated as present for purposes of determining the presence or absence of a quorum for all matters voted on at the SWM special meeting.

Votes Required; Effect of Abstentions and Failure to Vote

SWM share issuance proposal:

If you are an SWM stockholder entitled to vote at the SWM special meeting and you do not attend the SWM special meeting in person (via the Internet), return a proxy, or provide voting instructions to your

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brokerage firm, your shares will not be voted and will not be treated as present for purposes of establishing a quorum, and assuming a quorum is present, this will have no effect on the SWM share issuance proposal.

Because it is expected that all proposals to be voted on at the SWM special meeting will be “non-routine” matters, it is unlikely that there will be any broker non-votes at the SWM special meeting.

SWM adjournment proposal:

If you are an SWM stockholder entitled to vote at the SWM special meeting and you do not attend the SWM special meeting in person (via the Internet), return a proxy, or provide voting instructions to your brokerage firm, your shares will not be voted and will not be treated as present for purposes of establishing a quorum, and assuming a quorum is present, this will have no effect on the SWM adjournment proposal.

Because it is expected that all proposals to be voted on at the SWM special meeting will be “non-routine” matters, it is unlikely that there will be any broker non-votes at the SWM special meeting.

Shares Held by Officers and Directors

As of the SWM record date, the directors and executive officers of SWM and their affiliates beneficially owned and were entitled to vote approximately                  shares of SWM common stock representing approximately     % of the shares of SWM common stock outstanding on that date. It is expected that SWM’s directors and executive officers will vote their shares “FOR” the SWM share issuance proposal and “FOR” the SWM adjournment proposal. As of the SWM record date, Neenah, the directors and officers of Neenah and their affiliates beneficially owned no shares of SWM common stock outstanding on that date.

Voting of Proxies

Each copy of this joint proxy statement/prospectus mailed to SWM stockholders is accompanied by a form of proxy card with instructions for voting. If you hold shares in your name as a stockholder of record, you should complete and return the proxy card accompanying this joint proxy statement/prospectus, regardless of whether you plan to attend the SWM special meeting in person (via the Internet).

The procedures for voting by proxy are as follows:

SWM Stockholder of Record: Shares Registered in Your Name

If you are an SWM stockholder of record, you may vote in person (via the Internet) at the SWM special meeting. Alternatively, you may vote by proxy over the Internet, by telephone or by mail. Whether or not you plan to attend the SWM special meeting in person (via the Internet), we urge you to vote by proxy to ensure your vote is counted. Even if you have submitted a proxy before the SWM special meeting, you may still attend the SWM special meeting and vote in person (via the Internet). In such case, your previously submitted proxy will be disregarded. To enter the SWM special meeting, SWM stockholders will need the control number that

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is printed on their proxy cards. In order to attend the virtual meeting, you will need to pre-register by 8:00 a.m. Eastern Time on June 28, 2022 by visiting the website www.cesonlineservices.com/swm22_vm. SWM recommends that SWM stockholders log in at least fifteen minutes before the meeting to ensure that they are logged in when the meeting starts. Online check-in will start shortly before the meeting on June 29, 2022.

All shares represented by valid proxies that SWM receives through this solicitation, and that are not revoked, will be voted in accordance with your instructions on the proxy card. If you make no specification on your proxy card as to how you want your shares voted before signing and returning it, your proxy will be voted in accordance with the recommendation of the SWM board of directors with respect to such proposals. No matters other than the matters described in this joint proxy statement/prospectus are anticipated to be presented for action at the special meeting or at any adjournment or postponement of the SWM special meeting. However, if other business properly comes before the SWM special meeting, the proxy agents will, in their discretion, vote upon such matters in their best judgment.

Beneficial Owner: Shares Registered in the Name of Brokers, Banks or Other Nominees

If you are a beneficial owner of SWM shares registered in the name of your broker, bank or other nominee, you should have received a voting instruction card and voting instructions with these proxy materials from that organization rather than from us. Return the voting instructions as provided therein to ensure that your vote is counted. To vote in person (via the Internet) at the SWM special meeting, you must obtain a legal proxy from your broker, bank or other nominee. Follow the instructions from your broker, bank or other nominee included with these proxy materials, or contact your broker, bank or other nominee to request a proxy form.

Shares Held in “Street Name”; Broker Non-Votes

Under NYSE rules, banks, brokers and other nominees who hold shares of SWM common stock in “street name” for a beneficial owner of those shares typically have the authority to vote in their discretion on “routine” proposals when they have not received instructions from beneficial owners. However, banks, brokers and other nominees are not allowed to exercise their voting discretion with respect to the approval of matters determined to be “non-routine,” without specific instructions from the beneficial owner. If your broker, bank or other nominee holds your shares of SWM common stock in “street name,” your broker, bank or other nominee will vote your shares of SWM common stock only if you provide instructions on how to vote by filling out the voter instruction form sent to you by your broker, bank or other nominee with this joint proxy statement/prospectus.

Broker non-votes with respect to any proposal are shares held by a broker, bank or other nominee that are represented at the SWM special meeting because they are entitled to vote on at least one proposal, but with respect to which the broker or nominee does not have voting instructions from the beneficial owner or discretionary authority to vote on such specific proposal. Because it is expected that all proposals to be voted on at the SWM special meeting will be “non-routine” matters, it is unlikely that there will be any broker non-votes at the SWM special meeting. Broker non-votes, if any, will have no effect on any of the SWM proposals.

Revocability of Proxies and Changes to an SWM Stockholder’s Vote

If you hold your shares of SWM common stock in your name as a stockholder of record, you may revoke any proxy at any time before it is voted by (i) submitting another properly completed proxy over the Internet, by telephone or by mail with a later date, (ii) delivering a written revocation letter to SWM’s Secretary prior to the vote at the address below or (iii) attending the SWM special meeting in person (via the Internet) and voting by online ballot at such meeting.

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Any stockholder entitled to vote in person (via the Internet) at the SWM special meeting may vote online regardless of whether a proxy has been previously given, but the mere presence (without notifying SWM’s Secretary) of a stockholder at the SWM special meeting will not by itself constitute revocation of a previously given proxy.

Written notices of revocation and other communications about revoking your proxy should be addressed to:

Schweitzer-Mauduit International, Inc.

100 North Point Center East, Suite 600

Alpharetta, GA 30022

Attention: Executive Vice President, General Counsel and Secretary

If your shares of SWM common stock are held in “street name” by a broker, bank or other nominee, you should follow the instructions of your broker, bank or other nominee regarding the revocation of proxies.

Solicitation of Proxies

SWM is soliciting your proxy in conjunction with the merger. SWM will bear the cost of soliciting proxies from you. In addition to solicitation of proxies by mail, SWM will request that banks, brokers, nominees and any other holder of record send proxies and proxy material to the beneficial owners of SWM common stock and secure their voting instructions. SWM has also made arrangements with MacKenzie Partners, Inc. to assist it in soliciting proxies and has agreed to pay MacKenzie Partners, Inc. approximately $25,000 plus reasonable expenses for these services.

Householding of Proxy Materials

The SEC has adopted rules that permit companies and intermediaries (e.g., brokers) to satisfy the delivery requirements for proxy materials, including annual reports, with respect to two (2) or more stockholders sharing the same address by delivering a single copy of the documents addressed to those stockholders. This process, which is commonly referred to as “householding,” potentially means extra convenience for stockholders and cost savings for companies. In accordance with these rules, only one set of documents will be delivered to multiple stockholders sharing an address unless SWM has received contrary instructions from one or more of the stockholders.

If, at any time, you no longer wish to participate in “householding” and would prefer to receive separate copies of the proxy materials with respect to SWM, including annual reports, please notify your broker, and direct your written request to: Secretary, Schweitzer-Mauduit International, Inc., 100 North Point Center East, Suite 600, Alpharetta, Georgia 30022, or contact the office of SWM’s Secretary at (866) 528-2593. SWM stockholders who currently receive multiple copies of such documents and would like to request “householding” of their communications should contact their brokers.

Attending the SWM Special Meeting in Person (via the Internet)

All SWM stockholders, including holders of record and stockholders who hold their shares through banks, brokers, nominees or any other holder of record, are invited to attend the SWM special meeting in person (via the Internet). SWM stockholders of record can vote at the SWM special meeting in person (via the Internet). If you are not an SWM stockholder of record, you must obtain a proxy executed in your favor from the record holder of your shares, such as a broker, bank or other nominee, to be able to vote at the SWM special meeting in person (via the Internet).

To enter the SWM special meeting, SWM stockholders will need the control number that is printed on their proxy cards. In order to attend the virtual meeting, you will need to pre-register by 8:00 a.m. Eastern Time

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on June 28, 2022 by visiting the website www.cesonlineservices.com/swm22_vm. SWM recommends that SWM stockholders log in at least fifteen minutes before the meeting to ensure that they are logged in when the meeting starts. Online check-in will start shortly before the meeting on June 29, 2022.

Assistance

If you have any questions concerning the merger or this joint proxy statement/prospectus, would like additional copies of this joint proxy statement/prospectus or need help voting your shares of SWM common stock, please direct your inquiry to SWM’s proxy solicitor as follows:

MacKenzie Partners, Inc.

1407 Broadway, 27th Floor

New York, New York 10018

Call Toll-Free: 1-800-322-2885

Email: proxy@mackenziepartners.com

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SWM PROPOSALS

Proposal No. 1—SWM Share Issuance Proposal

At the SWM special meeting, the SWM stockholders will be asked to approve the issuance of shares of SWM common stock, pursuant to the terms of the merger agreement, in an amount necessary to complete the merger and the other transactions contemplated by the merger agreement. SWM stockholders should read this joint proxy statement/prospectus carefully and in its entirety, including the annexes, for more detailed information concerning the merger agreement and the merger. A copy of the merger agreement is attached to this joint proxy statement/prospectus as Annex A.

After careful consideration, the SWM board of directors unanimously adopted the merger agreement, authorized and approved the merger and the other transactions contemplated by the merger agreement and determined the merger agreement and the merger to be advisable and in the best interests of SWM and its stockholders. Please see “The Merger—SWM’s Reasons for the Merger; Recommendation of SWM’s Board of Directors” beginning on page 80 for a more detailed discussion of the SWM board of directors’ recommendation.

The SWM board of directors unanimously recommends that SWM stockholders vote “FOR” the SWM share issuance proposal.

Proposal No. 2—SWM Adjournment Proposal

The SWM special meeting may be adjourned from time to time to another time or place, if the chairperson of the meeting deems necessary or appropriate, including to permit further solicitation of proxies if necessary to obtain additional votes in favor of the SWM share issuance proposal or to ensure that any supplement or amendment to this joint proxy statement/prospectus is timely provided to SWM stockholders.

If, at the SWM special meeting, (i) there are insufficient shares of SWM common stock represented (either in person (via the Internet) or by proxy) to constitute a quorum necessary to conduct the business of such meeting, (ii) additional time is required for the filing and mailing of any supplemental or amended disclosure which SWM has determined is reasonably likely to be required under applicable law and for such supplemental or amended disclosure to be disseminated and reviewed by SWM stockholders prior to the meeting of SWM stockholders, (iii) to allow reasonable additional time to solicit additional proxies, if and to the extent SWM reasonably believes the number of shares of SWM common stock present or represented and voting in favor of the SWM share issuance proposal is insufficient to approve such proposal or (iv) if required by law, SWM intends to move to adjourn the SWM special meeting. In accordance with SWM’s bylaws, a vote to approve the proposal to adjourn the SWM special meeting, if necessary or appropriate, to solicit additional proxies if there are insufficient votes at the time of the SWM special meeting to adopt the SWM share issuance proposal may be taken in the absence of a quorum.

The SWM board of directors unanimously recommends that SWM stockholders vote “FOR” the SWM adjournment proposal.

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THE NEENAH SPECIAL MEETING

Date, Time and Place of Meeting

The Neenah special meeting will be held virtually via live webcast on the Internet at www.virtualshareholdermeeting.com/NP2022SM, on June 29, 2022, at 9:00 a.m. Eastern Time.

Matters to Be Considered

At the Neenah special meeting, Neenah stockholders will be asked to consider and vote upon the following matters:

Recommendation of the Neenah Board of Directors

The Neenah board of directors has (i) determined that the merger agreement and the transactions contemplated thereby, including the merger, are advisable, fair to and in the best interests of Neenah and its stockholders, (ii) approved and adopted the merger agreement and the execution, delivery and performance by Neenah of the merger agreement and the transactions contemplated thereby, including the merger, and (iii) recommended that Neenah’s stockholders approve the merger proposal. The Neenah board of directors unanimously recommends that Neenah stockholders vote “FOR” the Neenah merger proposal, “FOR” the Neenah compensation proposal, and “FOR” the Neenah adjournment proposal. See “The Merger— Neenah’s Reasons for the Merger; Recommendation of Neenah’s Board of Directors” beginning on page 92 for a more detailed discussion of the Neenah board of directors’ recommendation.

Neenah Record Date and Quorum

The Neenah board of directors has fixed the close of business on May 20, 2022, as the record date for determining the Neenah stockholders entitled to receive notice of and to vote at the Neenah special meeting and any adjournment or postponement thereof.

As of the Neenah record date, there were                  shares of Neenah common stock outstanding and entitled to vote at the Neenah special meeting held by approximately                  holders of record. Each share of Neenah common stock entitles the holder to one (1) vote at the Neenah special meeting on each proposal to be considered at the Neenah special meeting.

The presence at the Neenah special meeting, in person (via the Internet) or by proxy, of holders of a majority of the voting power of the Neenah common stock issued and outstanding and entitled to vote will constitute a quorum for the transaction of business. All shares of Neenah common stock present in person (via the Internet) or represented by proxy, including abstentions, will be treated as present for purposes of determining the presence or absence of a quorum for all matters voted on at the Neenah special meeting.

Votes Required; Effect of Abstentions and Failure to Vote

Neenah merger proposal:

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If you are a Neenah stockholder entitled to vote at the Neenah special meeting and you do not attend the Neenah special meeting in person (via the Internet) or return a proxy, your shares will not be voted and will not be treated as present for purposes of establishing a quorum, and such a failure to vote will have the effect of a vote “AGAINST” the Neenah merger proposal.

Because it is expected that all proposals to be voted on at the Neenah special meeting will be “non-routine” matters, it is unlikely that there will be any broker non-votes at the Neenah special meeting.

Neenah compensation proposal:

If you are a Neenah stockholder entitled to vote at the Neenah special meeting and you do not attend the Neenah special meeting in person (via the Internet) or return a proxy, your shares will not be voted, will not be treated as present for purposes of establishing a quorum and, assuming a quorum is present, this will have no effect on the Neenah compensation proposal.

Because it is expected that all proposals to be voted on at the Neenah special meeting will be “non-routine” matters, it is unlikely that there will be any broker non-votes at the Neenah special meeting.

Neenah adjournment proposal:

If you are a Neenah stockholder entitled to vote at the Neenah special meeting and you do not attend the Neenah special meeting in person (via the Internet) or return a proxy, your shares will not be voted, will not be treated as present for purposes of establishing a quorum and, assuming a quorum is present, this will have no effect on the Neenah adjournment proposal.

Because it is expected that all proposals to be voted on at the Neenah special meeting will be “non-routine” matters, it is unlikely that there will be any broker non-votes at the Neenah special meeting.

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Shares Held by Officers and Directors

As of the Neenah record date, the directors and executive officers of Neenah and their affiliates beneficially owned and were entitled to vote approximately                  shares of Neenah common stock representing approximately     % of the shares of Neenah common stock outstanding on that date. It is expected that Neenah’s directors and executive officers will vote their shares “FOR” the Neenah merger proposal, “FOR” the Neenah compensation proposal and “FOR” the Neenah adjournment proposal. As of the Neenah record date, SWM, the directors and officers of SWM and their affiliates beneficially owned no shares of Neenah common stock outstanding on that date.

Voting of Proxies

Each copy of this joint proxy statement/prospectus mailed to Neenah stockholders is accompanied by a form of proxy card with instructions for voting. If you hold shares in your name as a stockholder of record, you should complete and return the proxy card accompanying this joint proxy statement/prospectus, regardless of whether you plan to attend the Neenah special meeting in person (via the Internet).

The procedures for voting by proxy are as follows:

Neenah Stockholder of Record: Shares Registered in Your Name

If you are a Neenah stockholder of record, you may vote in person (via the Internet) at the Neenah special meeting. by visiting www.virtualshareholdermeeting.com/NP2022SM and using the 16-digit control number found on your proxy card. Neenah recommends that Neenah stockholders log in at least fifteen minutes before the special meeting begins to ensure that they are logged in when the meeting starts. Online check-in will start shortly before the meeting on June 29, 2022.

Alternatively, you may vote by proxy over the Internet, by telephone or by mail. Whether or not you plan to attend the Neenah special meeting in person (via the Internet), we urge you to vote by proxy to ensure your vote is counted. Even if you have submitted a proxy before the Neenah special meeting, you may still attend the Neenah special meeting and vote in person (via the Internet). In such case, your previously submitted proxy will be disregarded.

Beneficial Owner: Shares Registered in the Name of Brokers, Banks or Other Nominees

If you are a beneficial owner of Neenah shares registered in the name of your broker, bank or other nominee, you should have received a voting instruction card and voting instructions with these proxy materials from that organization rather than from us. Return the voting instructions as provided therein to ensure that your vote is counted. To vote at the Neenah special meeting in person (via the Internet), you must obtain a legal proxy from your broker, bank or other nominee. Follow the instructions from your broker, bank or other nominee included with these proxy materials, or contact your broker, bank or other nominee to request a proxy form.

All shares represented by valid proxies that Neenah receives through this solicitation, and that are not revoked, will be voted in accordance with your instructions on the proxy card. If you make no specification on your proxy card as to how you want your shares voted before signing and returning it, your proxy will be voted in accordance with the recommendation of the Neenah board of directors with respect to such proposals. No matters

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other than the matters described in this joint proxy statement/prospectus are anticipated to be presented for action at the Neenah special meeting or at any adjournment or postponement of the Neenah special meeting. However, if other business properly comes before the Neenah special meeting, the proxy agents will, in their discretion, vote upon such matters in their best judgment.

Shares Held in “Street Name”; Broker Non-Votes

Under NYSE rules, banks, brokers and other nominees who hold shares of Neenah common stock in “street name” for a beneficial owner of those shares typically have the authority to vote in their discretion on “routine” proposals when they have not received instructions from beneficial owners. However, banks, brokers and other nominees are not allowed to exercise their voting discretion with respect to the approval of matters determined to be “non-routine,” without specific instructions from the beneficial owner. If your broker, bank or other nominee holds your shares of Neenah common stock in “street name,” your broker, bank or other nominee will vote your shares of Neenah common stock only if you provide instructions on how to vote by filling out the voter instruction form sent to you by your broker, bank or other nominee with this joint proxy statement/prospectus.

Broker non-votes with respect to any proposal are shares held by a broker, bank or other nominee that are represented at the Neenah special meeting because they are entitled to vote on at least one proposal, but with respect to which the broker or nominee does not have voting instructions from the beneficial owner or discretionary authority to vote on such specific proposal. Because it is expected that all proposals to be voted on at the Neenah special meeting will be “non-routine” matters, it is unlikely that there will be any broker non-votes at the Neenah special meeting, and broker non-votes, if any, will have no effect on any of the Neenah proposals.

Revocability of Proxies and Changes to a Neenah Stockholder’s Vote

If you hold your shares of Neenah common stock in your name as a stockholder of record, you may revoke any proxy at any time before it is voted by (i) submitting another properly completed proxy over the Internet, by telephone or by mail with a later date, (ii) delivering a written revocation letter to Neenah’s Secretary prior to the vote at the address below or (iii) attending the Neenah special meeting in person (via the Internet) and voting by ballot online.

Any Neenah stockholder entitled to vote at the Neenah special meeting in person (via the Internet) may vote online regardless of whether a proxy has been previously given, but the mere presence (without notifying Neenah’s Secretary) of a stockholder at the Neenah special meeting will not by itself constitute revocation of a previously given proxy.

Written notices of revocation and other communications about revoking your proxy card should be addressed to:

Neenah, Inc.

3460 Preston Ridge Road, Suite 600

Alpharetta, Georgia 30005

Attention: Executive Vice President, General Counsel and Secretary

If your shares of Neenah common stock are held in “street name” by a broker, bank or other nominee, you should follow the instructions of your broker, bank or other nominee regarding the revocation of proxies.

Solicitation of Proxies

Neenah is soliciting your proxy in conjunction with the merger. Neenah will bear the cost of soliciting proxies from you. In addition to solicitation of proxies by mail, Neenah will request that banks, brokers, nominees and any other Neenah stockholders of record send proxies and proxy material to the beneficial owners of Neenah common stock and secure their voting instructions. Neenah has also made arrangements with Okapi Partners

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LLC, to assist it in soliciting proxies and has agreed to pay Okapi Partners LLC approximately $20,000 plus reasonable expenses for these services.

Householding of Proxy Materials

The SEC has adopted rules that permit companies and intermediaries (e.g., brokers) to satisfy the delivery requirements for proxy materials, including annual reports, with respect to two or more stockholders sharing the same address by delivering a single copy of the documents addressed to those stockholders. This process, which is commonly referred to as “householding,” potentially means extra convenience for stockholders and cost savings for companies. In accordance with these rules, only one set of documents will be delivered to multiple stockholders sharing an address unless Neenah has received contrary instructions from one or more of the stockholders.

If, at any time, you no longer wish to participate in “householding” and would prefer to receive separate copies of the proxy materials with respect to Neenah, including annual reports, please notify your broker and direct your written request to: Investor Relations, Neenah, Inc., 3460 Preston Ridge Road, Suite 600, Alpharetta, Georgia, 30005, or contact the office of Neenah’s Secretary at (678) 566-6500. Neenah stockholders who currently receive multiple copies of such documents and would like to request “householding” of their communications should contact their brokers.

Attending the Neenah Special Meeting in Person (via the Internet)

All Neenah stockholders, including holders of record and Neenah stockholders who hold their shares through banks, brokers, nominees or any other holder of record, are invited to attend the Neenah special meeting in person (via the Internet). Neenah stockholders of record can vote at the Neenah special meeting in person (via the Internet) by visiting www.virtualshareholdermeeting.com/NP2022SM and using the 16-digit control number found on their proxy card. If you are not a Neenah stockholder of record, you must obtain a proxy executed in your favor from the record holder of your shares, such as a broker, bank or other nominee, to be able to vote at the Neenah special meeting in person (via the Internet).

Neenah recommends that Neenah stockholders log in at least fifteen minutes before the meeting to ensure that they are logged in when the meeting starts. Online check-in will start shortly before the meeting on June 29, 2022.

Assistance

If you have any questions concerning the merger or this joint proxy statement/prospectus, would like additional copies of this joint proxy statement/prospectus, or need help voting your shares of Neenah common stock, please direct your inquiry to Neenah’s proxy solicitor as follows:

Okapi Partners LLC

1212 Avenue of the Americas, 24th Floor

New York, NY 10036

Call Toll-Free: 877-259-6290

Banks and Brokerage Firms Call: (212) 297-0720

Email: info@okapipartners.com

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NEENAH PROPOSALS

Proposal No. 1—Neenah Merger Proposal

At the Neenah special meeting, the Neenah stockholders will be asked to approve and adopt the merger agreement and the transactions contemplated thereby, including the merger. Neenah stockholders should read this joint proxy statement/prospectus carefully and in its entirety, including the annexes, for more detailed information concerning the merger agreement and the merger. A copy of the merger agreement is attached to this joint proxy statement/prospectus as Annex A.

After careful consideration, the Neenah board of directors unanimously (i) determined that the merger agreement and the transactions contemplated thereby, including the merger, are advisable, fair to and in the best interests of Neenah and its stockholders, (ii) approved and adopted the merger agreement and the execution, delivery and performance by Neenah of the merger agreement and the transactions contemplated thereby, including the merger, and (iii) recommended that Neenah’s stockholders approve the merger proposal. Please see “The Merger—Neenah’s Reasons for the Merger; Recommendation of Neenah’s Board of Directors” beginning on page 92 for a more detailed discussion of the Neenah board of directors’ recommendation.

The Neenah board of directors unanimously recommends that Neenah stockholders vote “FOR” the Neenah merger proposal.

Proposal No. 2—Neenah Compensation Proposal

Section 14A of the Exchange Act and Rule 14a-21(c) under the Exchange Act requires Neenah to seek a nonbinding advisory vote from its stockholders to approve the “golden parachute” compensation that may be paid or become payable to Neenah’s named executive officers that is based on or otherwise relates to the merger, as disclosed in “The Merger—Neenah’s Reasons for the Merger; Recommendation of Neenah’s Board of Directors” beginning on page 92, including the table titled “Merger-Related Compensation for Neenah’s Named Executive Officers” and its accompanying footnotes. As required by these provisions, Neenah is asking the Neenah stockholders to cast an advisory vote on the adoption of the following resolution:

“RESOLVED, that the compensation that may be paid or become payable to Neenah’s named executive officers that is based on or otherwise relates to the merger, and the agreements or understandings pursuant to which such compensation may be paid or become payable, in each case, as disclosed pursuant to Item 402(t) of Regulation S-K in “The Merger—Interests of Neenah’s Directors and Executive Officers in the Merger” and “The Merger—Merger-Related Compensation for Neenah’s Named Executive Officers” beginning on pages 92 and 114, respectively, are hereby APPROVED.”

The vote on the Neenah compensation proposal is an advisory vote and will not be binding on Neenah, Neenah’s board of directors, SWM, any of Neenah or SWM’s subsidiaries or the combined company. Therefore, regardless of whether Neenah stockholders approve the Neenah compensation proposal, if the Neenah merger proposal is approved by the Neenah stockholders and the merger is completed, the compensation that may be paid or become payable to Neenah’s named executive officers that is based on or otherwise related to the merger will still be paid to such officers in accordance with the terms of their compensation agreements and arrangements. Approval of the Neenah compensation proposal is not a condition to the closing of the merger.

The Neenah board of directors unanimously recommends that Neenah stockholders vote “FOR” the Neenah compensation proposal.

Proposal No. 3 — Neenah Adjournment Proposal

The Neenah special meeting may be adjourned from time to time to another time or place, if the chairperson of the meeting determines necessary or appropriate, to permit, among other things, further solicitation of proxies if

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necessary to obtain additional votes in favor of the Neenah merger proposal or to ensure that any supplement or amendment to this joint proxy statement/prospectus is timely provided to Neenah stockholders.

If, at the Neenah special meeting, (i) there are insufficient shares of Neenah common stock represented (either in person (via the Internet) or by proxy) to constitute a quorum necessary to conduct the business of such meeting, (ii) additional time is required for the filing and mailing of any supplemental or amended disclosure which Neenah has determined is reasonably likely to be required under applicable law and for such supplemental or amended disclosure to be disseminated and reviewed by Neenah stockholders prior to the special meeting of Neenah stockholders, (iii) to allow reasonable additional time to solicit additional proxies, if and to the extent Neenah reasonably believes the number of shares of Neenah common stock present or represented and voting in favor of the Neenah merger proposal is insufficient to approve such proposal or (iv) if required by law, Neenah intends to move to adjourn the Neenah special meeting. In accordance with Neenah’s bylaws, a vote to approve the proposal to adjourn the Neenah special meeting, if necessary or appropriate, to solicit additional proxies if there are insufficient votes at the time of the Neenah special meeting to adopt the Neenah merger proposal may be taken in the absence of a quorum.

The Neenah board of directors unanimously recommends that Neenah stockholders vote “FOR” the Neenah adjournment proposal.

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THE MERGER

This section of the joint proxy statement/prospectus describes material aspects of the merger. This summary may not contain all of the information that is important to you. You should carefully read this entire joint proxy statement/prospectus and the other documents attached to or incorporated by reference for a more complete understanding of the merger and the merger agreement. In addition, we incorporate important business and financial information about each of SWM and Neenah into this joint proxy statement/prospectus by reference. You may obtain the information incorporated by reference into this joint proxy statement/prospectus without charge by following the instructions in the section entitled “Where You Can Find More Information” beginning on page 188.

Terms of the Merger

Each of the SWM and Neenah boards of directors has unanimously adopted and approved the merger agreement. The merger agreement provides that SWM and Neenah will combine their companies in a merger of equals, structured as a merger of Merger Sub with and into Neenah, with Neenah as the surviving corporation and a wholly owned subsidiary of SWM.

In the merger, each share of Neenah common stock issued and outstanding immediately prior to the effective time (other than certain shares owned by SWM or any of its wholly owned subsidiaries, including Merger Sub, or Neenah or any of its wholly owned subsidiaries) will be converted into the right to receive 1.358 shares of SWM common stock. No fractional shares of SWM common stock will be issued in connection with the merger, and Neenah stockholders will be entitled to receive cash in lieu thereof.

SWM stockholders are being asked to approve the issuance of SWM common stock as the merger consideration in the merger, and Neenah stockholders are being asked to approve the merger agreement, the merger and the other transactions contemplated thereby. See the section entitled “The Merger Agreement” beginning on page 128 for additional and more detailed information regarding the legal documents that govern the merger, including information about the conditions to the completion of the merger and the provisions for terminating or amending the merger agreement.

Background of the Merger

The respective boards of directors of each of SWM and Neenah, together with their respective management teams, regularly review and assess the performance, strategy, competitive position, opportunities and prospects of their respective companies in light of the then-current business, economic and regulatory environments, as well as developments in the specialty products and other industries in which each company operates, in each case with the goal of enhancing long-term value for their respective stockholders. These reviews conducted by each company have included periodic consideration and discussion of potential strategic alternatives, including whether such company should continue to execute on its strategy as a stand-alone company; pursue various dispositions, acquisitions, business combinations or joint ventures; or seek to improve its capital structure, which could include deleveraging. As part of these reviews, the Chief Executive Officer of each company engages, from time to time, in informal discussions with key representatives of other companies regarding trends and developments, and, on occasion, strategic alternatives available to such company, including potential business combinations and other strategic transactions.

As a result of each company’s commitment to periodically evaluating strategic alternatives, during July and August 2019, John O’Donnell, the President and Chief Executive Officer of Neenah at that time, and Dr. Jeff Kramer, the Chief Executive Officer of SWM, engaged in preliminary discussions regarding possible strategic advantages in working together to gauge each company’s interest in pursuing a potential business combination or other strategic transaction with the other company. To facilitate that discussion, on August 13, 2019, Neenah and SWM entered into a mutual non-disclosure agreement as part of preliminary discussions regarding the exploration of a potential transaction, but no confidential information was exchanged between the parties at that

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time. While these preliminary discussions did not result in any specific proposal for a strategic transaction, Neenah and SWM determined that the potential strategic opportunities between the parties warranted a review with their respective boards. The preliminary discussions were reviewed by Neenah at a regular meeting of the Neenah board of directors on August 14-15, 2019, and by SWM at a meeting of the SWM board of directors on August 16, 2019. After reviewing and discussing the state of the industry at the time and potential strategic alternatives then-available to Neenah, the Neenah board of directors determined not to move forward with the commencement of due diligence or negotiation of potential transaction terms at that time, and that Neenah should instead continue to focus on executing on its then-current strategy and operating as an independent, stand-alone company.

Following these preliminary discussions, both SWM and Neenah continued to focus on executing their respective stand-alone strategic plans, including the review and execution of strategic acquisitions.

On February 1, 2020, Neenah announced that it had entered into a definitive agreement to acquire Vectorply Corporation, a composites media manufacturing company based in the United States. Neenah ultimately did not consummate that proposed transaction based on a number of considerations, including those related to the uncertainty of global markets at the beginning of the COVID-19 pandemic.

On February 11, 2020, Neenah announced that Ms. Schertell was appointed as the Chief Executive Officer of Neenah effective May 21, 2020.

On March 13, 2020, SWM acquired Tekra, LLC and Trient, LLC, converters of high-performance films and substrates based in the United States.

On April 6, 2021, Neenah acquired Global Release Liners, S.L., the parent company of Industrias de Transformación de Andoain, S.A., a manufacturer of release liner media headquartered in Spain, with additional operations in Mexico and Malaysia.

On April 15, 2021, SWM acquired Scapa Group Plc (which we refer to as “Scapa”), a UK-based innovation, design and manufacturing solutions provider for healthcare and industrial markets.

In August 2021, Dr. Kramer contacted Ms. Schertell to schedule an in-person introductory meeting to be held on September 3, 2021, as Dr. Kramer and Ms. Schertell had not met since Ms. Schertell was appointed as the Chief Executive Officer of Neenah. Prior to the meeting and to ensure that she had the relevant background regarding Neenah’s past interactions with SWM, on August 27, 2021, Ms. Schertell contacted Perella Weinberg to discuss the history of the interactions and discussions between Mr. O’Donnell and Dr. Kramer.

On September 3, 2021, Ms. Schertell and Dr. Kramer attended the scheduled in-person meeting, at which they discussed general industry conditions, each company’s ongoing business performance, as well as the prior CEO to CEO discussions in 2019 regarding a potential transaction. At this meeting, both Dr. Kramer and Ms. Schertell expressed that their respective company was focused on executing its respective strategy as an independent, stand-alone company, but that the board of directors of each company regularly reviews and assesses strategic alternatives that could enhance stockholder value and may be interested in exploring a potential combination of SWM and Neenah. No definitive terms of a proposed transaction were discussed during this meeting.

Following the September 3, 2021, meeting, Dr. Kramer updated SWM’s non-executive chair, Dr. John D. Rogers, on his discussion with Ms. Schertell. Dr. Kramer noted to Dr. Rogers that SWM should continue to execute its current strategy and operate as an independent company, but should also evaluate a potential business combination transaction with Neenah. Dr. Rogers expressed preliminary support for continued, exploratory discussions with Neenah.

Following the September 3, 2021, meeting, Ms. Schertell updated Neenah’s non-executive chair, William Cook, on her discussion with Dr. Kramer. Mr. Cook noted to Ms. Schertell the general view of the Neenah board of

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directors that Neenah should continue to focus on its current strategy as an independent stand-alone company, but that Neenah should also continue to evaluate strategic alternatives that could enhance stockholder value, including a possible combination of SWM and Neenah.

On September 22, 2021, Dr. Kramer and Ms. Schertell held a telephone call to further discuss each company’s ongoing business performance and the strategic merits of a potential combination of SWM and Neenah so that each could provide additional information to its board of directors.

On September 23, 2021, the SWM board of directors held a meeting with members of SWM’s senior management. During an executive session of the meeting, Dr. Kramer reported to the SWM board of directors the discussions he had with Ms. Schertell regarding a potential combination of SWM and Neenah. The SWM board of directors discussed the potential combination, including its potential risks and benefits, in addition to other strategic alternatives. The SWM board of directors also discussed SWM’s strategy as an independent, stand-alone company and confirmed its continued confidence in SWM’s strategy as an independent, stand-alone company and the value creation anticipated therefrom for SWM and its stockholders. Following discussion, the SWM board of directors directed Dr. Kramer to continue to engage in discussions with Ms. Schertell and proceed with an evaluation of the benefits and risks of a potential combination of SWM and Neenah so that the SWM board of directors could further assess the transaction.

On September 24, 2021, the Neenah board of directors held a telephone call with members of Neenah’s senior management. During the call, Ms. Schertell discussed with the Neenah board of directors the discussions she had with Dr. Kramer regarding a potential combination of SWM and Neenah. The Neenah board of directors discussed the potential combination, including its potential risks and benefits, in addition to other strategic alternatives. With respect to the potential combination, among the factors considered by the Neenah board of directors were the potentially complementary businesses, the potential for synergies and the potential for benefits related to increased scale and a strengthened financial profile. The Neenah board of directors also discussed Neenah’s strategy as an independent, stand-alone company and confirmed its continued confidence in Neenah’s strategy as an independent, stand-alone company and the value creation anticipated therefrom for Neenah and its stockholders. As part of this discussion, Neenah’s independent directors acknowledged the progress they felt Neenah’s management had been making in executing Neenah’s strategic plan and setting up the company for long-term success, and expressed their view that, if the two companies ultimately determined to move forward with the potential combination, Ms. Schertell should likely continue to play an integral role as Chief Executive Officer of the combined company, given their confidence in Ms. Schertell and her ability to unlock the potential benefits of the potential combination. However, Neenah’s independent directors also determined that Neenah should focus on its diligence evaluation of SWM and the potential synergies and benefits associated with a combination with SWM, and that the Chief Executive Officer role and other governance aspects of the combined company should be considered by the Neenah board of directors once it had a better understanding of a potential combination of SWM and Neenah. Following discussion, the Neenah board of directors directed Ms. Schertell to continue to engage in discussions with Dr. Kramer and proceed with an evaluation of the benefits and risks of a potential combination of SWM and Neenah so that the Neenah board of directors could further assess the transaction.

On October 29, 2021, the Neenah board of directors held a telephone call with members of Neenah’s senior management. During the call, the Neenah board of directors again discussed the meetings and calls between Ms. Schertell and Dr. Kramer and the potential combination of SWM and Neenah, including strategic rationale and potential acceleration of growth.

On November 5, 2021, Dr. Kramer and Ms. Schertell held a telephone call to discuss both parties’ initial reflections on the potential combination of SWM and Neenah and potential next steps for the evaluation of the potential combination. As part of this discussion, Dr. Kramer and Ms. Schertell agreed that a thorough evaluation

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of the industrial logic, strategic fit and synergy potential of a combination of Neenah and SWM, as well as the costs of achieving such synergies, must be a key next step as part of each of SWM’s and Neenah’s evaluation of a potential transaction.

In early November, each of Neenah and SWM internally discussed the possibility of conducting an evaluation of each company’s business and the potential combination through each company sharing nonpublic information with third party advisors (rather than directly with the other party) in a “clean room” diligence exercise (which we refer to as the “clean room diligence evaluation”), subject to approval by each company’s board of directors.

Between September and November 2021, Dr. Kramer provided Dr. Rogers with additional updates on the discussions Dr. Kramer had with Ms. Schertell regarding a potential business combination transaction with Neenah. Dr. Rogers continued to express preliminary support for continued exploratory discussions and also encouraged Dr. Kramer to engage external advisors at the appropriate time to allow SWM to evaluate a potential transaction. During such time, SWM’s senior management also began preparing for the continued evaluation of a potential business combination transaction, including gathering internal diligence information, assessing area of focus for the potential clean room diligence evaluation, evaluating possible financial and legal advisors and discussing potential transaction structures for such a combination.

On November 16-18, 2021, the Neenah board of directors held a regularly scheduled meeting. Representatives of Neenah’s legal counsel, Bryan Cave Leighton Paisner LLP (which we refer to as “BCLP”), were in attendance. Representatives of Perella Weinberg, which had acted as Neenah’s financial advisor in connection with its prior acquisition of Global Release Liners, S.L. and were familiar with Neenah’s business and strategies, as well as Mr. O’Donnell’s preliminary discussions with Dr. Kramer in 2019, were also in attendance as part of an annual review of Neenah’s long-term financials and strategic alternatives. At the meeting, Ms. Schertell reported to the Neenah board of directors on the latest discussions she had with Dr. Kramer regarding a potential combination of SWM and Neenah. Representatives of Perella Weinberg discussed their preliminary financial perspectives regarding Neenah, and the risks, opportunities and alternatives specific to Neenah’s long-term strategy. Further, at the request of Ms. Schertell, representatives of Perella Weinberg discussed potential strategic alternatives which could be available to Neenah, including a potential business combination with SWM and continuing to focus on executing management’s current strategy and operating as an independent, stand-alone company. Following the discussion, the Neenah board of directors directed Ms. Schertell to continue to engage in initial discussions with Dr. Kramer to finalize a path forward for an evaluation of a potential combination of SWM and Neenah, in order to assess the industrial logic, strategic fit and synergy potential of the potential combination of Neenah and SWM and to also engage in the clean room diligence evaluation. The Neenah board of directors also directed Ms. Schertell to schedule a meeting involving Ms. Schertell, Dr. Kramer and the non-executive chair of each company’s board of directors.

On November 22, 2021, Ms. Schertell and Dr. Kramer discussed scheduling an in-person discussion among Ms. Schertell, Mr. Cook, Dr. Kramer and Dr. Rogers in January 2022. Dr. Kramer and Ms. Schertell agreed that getting an advance date on the calendar would be beneficial while Dr. Kramer and Ms. Schertell continued their preliminary, exploratory discussions. After this discussion, Dr. Kramer provided Dr. Rogers with an update regarding the proposed January meeting. Dr. Rogers also noted that he and the rest of the SWM board of directors would likely be amenable to a meeting if the general governance framework of the potential combined company could be advanced prior to such meeting. Ms. Schertell also provided Mr. Cook with an update regarding the proposed January meeting.

On November 30, 2021, SWM and Neenah agreed to extend the term of their mutual non-disclosure agreement through November 30, 2024 to further explore a potential transaction.

On December 6, 2021, Dr. Kramer and Ms. Schertell held a telephone call to discuss the feedback from each company’s board of directors and to plan an in-person meeting for December 13, 2021, at which they would discuss the parties’ potential interest in moving forward with a preliminary evaluation and plan the path forward

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for such evaluation. Dr. Kramer and Ms. Schertell also generally discussed a potential transaction timeline and the process for the clean room diligence evaluation. After this discussion, Dr. Kramer provided Dr. Rogers with an update regarding the proposal for an in-person meeting on December 13, 2021, and Ms. Schertell provided Mr. Cook with an update regarding the call with Dr. Kramer.

On December 9, 2021, the SWM board of directors held a meeting with members of SWM’s senior management also in attendance. At the meeting, Dr. Kramer reviewed his discussions with Ms. Schertell regarding a potential business combination transaction with Neenah, as well as the proposed December 13, 2021, meeting between Dr. Kramer and Ms. Schertell. The SWM board of directors and SWM’s senior management also reviewed strategic alternatives available to SWM, including other potential business combinations, a sale of part or all of SWM, other strategic transactions and continuing to focus on executing management’s current strategies and operating as an independent, stand-alone company. During this discussion, Dr. Kramer recommended to the SWM board of directors that SWM continue to execute its current strategy and operate as an independent company, while also evaluating a potential business combination transaction with Neenah. Dr. Kramer also presented the SWM board of directors with a formal approach on how to pursue a step-by-step approach to evaluating the value of such a transaction, which included a potential upcoming discussion with Ms. Schertell regarding the general governance framework of the potential combined company. The SWM board of directors noted the need to validate the synergy potential of a combination of Neenah and SWM, as well as the costs of achieving such synergies, in order to fully evaluate the merits of a potential business combination. Following discussion, the SWM board of directors expressed support for Dr. Kramer’s recommendation and authorized SWM’s management to engage external advisors to assist SWM with an evaluation of a potential business combination transaction and the clean room diligence evaluation. The SWM board of directors also expressed its support for the December 13, 2021, meeting between Dr. Kramer and Ms. Schertell and agreed that a discussion of the general governance framework for the combined company should be on the agenda for such meeting.

On December 13, 2021, Ms. Schertell and Dr. Kramer met in person to align on the focus and process of the clean room diligence evaluation in order to ensure that this evaluation would be conducted in a manner that would allow both parties to fully assess the industrial logic, strategic fit and synergy potential of the potential combination of SWM and Neenah. Ms. Schertell and Dr. Kramer also agreed that a potential general framework for the governance of the combined company for consideration by the SWM and Neenah boards of directors would be important for the SWM and Neenah boards of directors to fully evaluate a potential business combination. Ms. Schertell and Dr. Kramer discussed the possibility of Ms. Schertell serving as the Chief Executive Officer of the combined company, with Dr. Kramer having an advisory role following the closing, if the SWM board of directors and Neenah board of directors were to deem it appropriate. Dr. Kramer also noted that, if the Neenah board of directors deemed it appropriate for Ms. Schertell to serve as the Chief Executive Officer of the combined company, he believed SWM’s board of directors would deem it appropriate for SWM to have the right to designate the chair of the board. Dr. Kramer and Ms. Schertell agreed to further discuss these social and governance issues with the SWM board of directors and Neenah board of directors, respectively.

Following this meeting, Dr. Kramer provided Dr. Rogers with an update regarding his meeting with Ms. Schertell and the discussions regarding the potential governance framework for the combined company. Dr. Kramer noted to Dr. Rogers that if the SWM board of directors was supportive of a potential business combination, Dr. Kramer was amenable to serving in an advisory role post-closing with Ms. Schertell serving as the Chief Executive Officer of the combined company, so long as the board of directors of the combined company was comprised of a majority of directors designated by SWM, with SWM also having the right to designate the chair of the board of directors of the potential combined company. Dr. Rogers expressed his view that, subject to further discussions with the SWM board at a later date, this potential governance framework was sufficient for Ms. Schertell, Mr. Cook, Dr. Kramer and Dr. Rogers to meet in January to continue discussions regarding a potential business combination

On December 17, 2021, the Neenah board of directors held a telephone call with members of Neenah’s senior management. During the call, Ms. Schertell reported to the Neenah board of directors on the latest discussions

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she had with Dr. Kramer regarding a potential combination of SWM and Neenah, including the plans for the clean room diligence evaluation, the plans for a January dinner meeting involving Ms. Schertell, Mr. Cook, Dr. Kramer and Dr. Rogers in order to further discuss the potential combination and their discussions regarding the Chief Executive Officer role in the combined company, chair of the board of directors of the potential combined company and Dr. Kramer’s potential advisory role in the combined company. The Neenah board of directors also further discussed the industrial logic, strategic fit and synergy potential of a combination of Neenah and SWM, and other strategic alternatives available to Neenah. As part of this discussion, Neenah’s independent directors again expressed their view that, if the two companies ultimately determined to move forward with the potential combination, Ms. Schertell should likely continue to play an integral role as Chief Executive Officer of the combined company, given their confidence in Ms. Schertell and her ability to unlock the potential benefits of the potential combination, and also that Dr. Kramer should serve in an advisory role as it would be beneficial to the combined company following the closing. Following discussion, the Neenah board of directors directed Neenah management to continue with an evaluation of a potential combination between Neenah and SWM, including further discussions of potential governance structures and operational aspects of the combined company, while continuing to execute its current strategy and operating as an independent, stand-alone company. The Neenah board of directors specifically noted the need to analyze and confirm the industrial logic, strategic fit and synergy potential of the potential combination of Neenah and SWM, in order to fully evaluate the potential combination. The Neenah board of directors also expressed its support for the planned January dinner meeting between Ms. Schertell, Mr. Cook, Dr. Kramer and Dr. Rogers.

On December 20, 2021, SWM engaged J.P. Morgan to act as SWM’s financial advisor for purposes of evaluating a potential transaction. SWM engaged J.P. Morgan due to the fact that, among other matters, J.P. Morgan had acted as SWM’s financial advisor in connection with its prior acquisition of Scapa and was familiar with SWM’s business and strategies as well as SWM’s preliminary discussions with Neenah’s prior Chief Executive Officer regarding a potential transaction. J.P. Morgan’s engagement was formalized in an engagement letter by and between SWM and J.P. Morgan on January 16, 2022.

On January 11, 2022, Ms. Schertell, Mr. Cook, Dr. Kramer and Dr. Rogers attended the scheduled dinner meeting and discussed the potential opportunity to combine Neenah and SWM and the value creation potential for their respective stockholders in a merger of equals transaction between the parties. None of the parties at this meeting proposed any specific transaction terms. The parties also agreed that in addition to further discussions regarding the specifics of the governance of the combined company, SWM’s and Neenah’s continued evaluation of a potential merger of equals transaction should focus primarily on the industrial logic, strategic fit and synergy potential of a combination of Neenah and SWM.

Throughout December 2021 and January 2022, Neenah’s senior management continued to work with Perella Weinberg to evaluate a potential merger of equals transaction, and SWM’s senior management team also continued to work with J.P. Morgan to evaluate a potential merger of equals transaction. During that time, both parties’ senior management teams also met with selected consulting firms to evaluate proposals to assist with diligence, with both parties ultimately agreeing to jointly engage EY-Parthenon (which we refer to as “EY”) on or about January 23, 2022, to evaluate the synergy potential of a merger of equals transaction and advise both parties through the diligence evaluation.

On January 14, 2022, Neenah’s independent directors held a meeting, during which Mr. Cook reported to Neenah’s independent directors on the discussions among Ms. Schertell, Mr. Cook, Dr. Kramer and Dr. Rogers at the January 11, 2022 dinner meeting. Mr. Cook responded to questions from Neenah’s other independent directors, and Neenah’s independent directors discussed the dinner meeting and the potential merger of equals transaction, including the industrial logic, strategic fit and synergy potential of a combination of Neenah and SWM and the timeline and process for the merger generally.

On January 24, 2022, members of both Neenah’s and SWM’s respective senior management teams attended a meeting to jointly review the management presentations prepared by each of Neenah and SWM. Also present at this meeting were representatives of EY, Perella Weinberg and J.P. Morgan. The management presentations were

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presented by each senior leadership team and were designed to allow each company’s senior management and financial advisors to continue to evaluate the strategic logic of a potential merger of equals transaction between the companies. The management presentations focused on various financial and operational aspects of the two companies, including the industrial logic, strategic fit and synergy potential of a potential merger of equals transaction.

On January 26-27, 2022, the Neenah board of directors held a regularly scheduled meeting, during which an executive session of the Neenah board of directors was held with Perella Weinberg, Ms. Schertell and Noah Benz, Executive Vice President, General Counsel and Secretary of Neenah, in attendance. During this executive session, Ms. Schertell provided the Neenah board of directors with an update on the management presentations, as well as the status of discussions with SWM and preparations for the clean room diligence evaluation. Ms. Schertell discussed with the Neenah board of directors how the information gathered during Neenah’s initial evaluation of SWM and a potential combination of the two companies by Neenah’s management made the potential merger of equals transaction even more attractive than initially anticipated, with numerous opportunities for significant value creation. Senior management further presented to the Neenah board of directors an overview of their to-date diligence evaluation of SWM, a strategic combination hypothesis, SWM’s fit with Neenah’s current portfolio, and an update on the process generally. Representatives from Perella Weinberg also discussed their views regarding the value that could be created in the potential merger of equals transaction, including the benefits of the increased scale of the combined company, potential strategic synergies and a potentially greater interest from analysts and investors given the increased scale. The Neenah board of directors discussed the merits of the potential merger of equals transaction, including potential value creation through complementary businesses, growth acceleration potential, synergies, strategic combination hypothesis, scale opportunities and a strengthened financial profile. Ms. Schertell described the engagement of EY to conduct an independent review of the potential synergies and value creation of the potential merger of equals transaction. The Neenah board of directors also reviewed Neenah’s business plan and projections if it were to remain an independent, stand-alone company, and confirmed their continued confidence in Neenah’s strategy as an independent, stand-alone company and the value creation anticipated therefrom for Neenah and its stockholders. Following a discussion by Neenah’s independent directors in an executive session of the independent directors, the Neenah board of directors directed Ms. Schertell to continue with the evaluation of the merits of the potential merger of equals transaction, including further discussions of potential governance structures and operational aspects of the combined company, so that the Neenah board of directors could further assess the transaction and the company’s options generally.

On January 28, 2022, Dr. Kramer and Ms. Schertell held a telephone call to discuss the feedback from the Neenah board of directors meeting. Ms. Schertell informed Dr. Kramer that the Neenah board of directors continued to support moving forward with the clean room diligence evaluation to be conducted by EY. Dr. Kramer and Ms. Schertell further discussed next steps for each team to interact with EY, populate the virtual data room with the data necessary for EY to complete its analysis and coordinate additional next steps. Dr. Kramer and Ms. Schertell also agreed to meet again the following week to discuss the progress of both companies’ diligence evaluations.

On February 7, 2022, Dr. Kramer and Ms. Schertell held a telephone call to discuss due diligence and the initial progress on the clean room diligence evaluation. Dr. Kramer and Ms. Schertell also discussed the input they received from their respective boards of directors regarding the potential governance framework for the combined company. Ms. Schertell noted that, while the Neenah board of directors continued to evaluate the proposed combination and the potential governance framework for the combined company, the initial view of Neenah’s independent directors was that Ms. Schertell should serve as Chief Executive Officer of the combined company. Dr. Kramer noted that SWM’s independent directors had indicated that they would be amenable to discussing Ms. Schertell’s role as the Chief Executive Officer of the combined company, subject to continued evaluation of the proposed combination and the potential governance framework of the combined company. Each noted that their respective boards of directors had also indicated that they would likely be supportive of Dr. Kramer serving in an advisory role following the closing and also supportive of the SWM chair serving as the non-executive chair of the combined company, subject to continued evaluation of the proposed combination and

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the potential governance framework of the combined company. Dr. Kramer and Ms. Schertell further noted that additional discussions and determinations, including by each company’s board of directors, would be required regarding the potential governance framework of the combined company and other social and governance issues, but that such discussion should be subject to the parties’ continued focus on the industrial logic, strategic fit and synergy potential of a combination of Neenah and SWM.

Following the February 7, 2022 call between Dr. Kramer and Ms. Schertell, Dr. Kramer updated Dr. Rogers on these discussions.

In early February 2022, Neenah instructed BCLP to assist with a legal due diligence review of the publicly-available information related to SWM, and on or about February 21, 2022, BCLP delivered a preliminary legal due diligence memorandum to Neenah.

On February 17, 2022, members of SWM’s senior management team met with the SWM board of directors to provide an update on the potential transaction and the progress and findings of the clean room diligence. Representatives of J.P. Morgan were also in attendance at this meeting. During the meeting, SWM’s senior management reviewed with the SWM board of directors the merits of the potential merger of equals transaction, including potential value creation through complementary businesses, growth acceleration potential, synergies, strategic combination hypothesis, scale opportunities and a strengthened financial profile. SWM’s senior management further presented to the SWM board of directors an overview of their to-date diligence evaluation of Neenah, a strategic combination hypothesis, SWM’s fit with Neenah’s current portfolio, and an update on the process generally. Dr. Kramer reviewed with the SWM board of directors the discussions he had with Ms. Schertell regarding the potential governance framework for the combined company. As part of this discussion, Dr. Kramer noted that, if the SWM board of directors determined that a potential merger of equals transaction had the potential to enhance value for SWM stockholders and deliver the best possible products for SWM’s customers and communities, then he was amenable to a governance framework whereby Ms. Schertell would serve as the Chief Executive Officer of the combined company, he would serve in an advisory role following the closing, and the SWM chair would serve as the non-executive chair of the combined company. Dr. Kramer also discussed with SWM’s board of directors his belief that a governance framework in which a majority of the members of the board of directors were designated by SWM would likely be acceptable to Neenah.

Also during this meeting of the SWM board of directors, representatives of J.P. Morgan discussed certain key considerations that typically arise in a merger of equals transaction, including among other matters, the pro forma stockholder ownership of the combined company, the go-forward governance of the combined company, including appointment of members of management and the composition of the board of directors and committees of the board of directors, and certain other issues regarding the combined company, including selection of the headquarters and name of the combined company. Representatives of J.P. Morgan also reviewed with the SWM board of directors a historical exchange ratio analysis for SWM’s and Neenah’s common stock and the overlap in SWM’s and Neenah’s stockholder base. Following discussion, the SWM board of directors reiterated its support for the continued evaluation of a potential merger of equals transaction with Neenah.

On February 18, 2022, EY provided a preliminary synergies analysis to Neenah’s and SWM’s senior management teams, with representatives of both parties’ financial advisors in attendance. EY shared its initial feedback based on the diligence evaluation of publicly-available information, and the parties’ management teams discussed additional priority areas for continued diligence.

On February 21, 2022, Dr. Kramer and Ms. Schertell held a telephone call to discuss the preliminary synergy analysis and the potential operating model and business unit structure of the proposed combined company. Dr. Kramer and Ms. Schertell agreed that significant synergy potential and strategic logic had been identified in EY’s initial analysis. Dr. Kramer and Ms. Schertell discussed their preliminary thoughts on a potential exchange

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ratio. No specific exchange ratio or pro forma ownership of the combined company was discussed by Dr. Kramer or Ms. Schertell during this call, though Dr. Kramer and Ms. Schertell agreed that any exchange ratio and pro forma ownership should be determined over an appropriate historic period that fairly valued both parties’ respective businesses. Dr. Kramer and Ms. Schertell also discussed how the composition of the board of directors of the proposed combined company would need to be agreed if the parties moved forward with the potential merger of equals transaction.

On February 22, 2022, the Neenah board of directors held a special meeting to discuss updates regarding the potential merger of equals transaction. Members of Neenah’s senior management team and representatives of Perella Weinberg were also in attendance at this meeting. During the meeting, senior management reviewed an illustrative transaction timeline and transaction workstreams, key diligence workstreams and findings, including with respect to the preliminary legal due diligence memorandum prepared by BCLP, and the Neenah board of directors, senior management and Perella Weinberg discussed the potential value and benefits of such a transaction to Neenah and its stockholders, including the synergy potential and other value creation opportunities (including from the significant increase in scale and improved strategic position of the combined company, particularly in light of the current industry landscape and the increasing focus on scale and consolidation among key peers of the companies), the tax-efficient nature of the transaction and the meaningful financial flexibility of the combined company. Perella Weinberg also reviewed with the Neenah board of directors certain preliminary aspects of the relative equity valuations and other metrics of the two companies, which Perella Weinberg advised the Neenah board of directors were consistent with merger of equals transactions. Senior management reviewed the synergy analysis performed by EY. Ms. Schertell also provided the Neenah board of directors with another update on her discussions with Dr. Kramer, including their discussions regarding the CEO role in a potential combined company and each of Ms. Schertell’s and Dr. Kramer’s interests in potentially continuing in that role, discussions regarding Dr. Kramer potentially having an advisory role following the closing, discussions regarding SWM’s chair potentially serving as non-executive chair of the combined company and discussions regarding the potential apportionment of seats for the board of directors of the combined company between the two companies. The Neenah board of directors and senior management agreed that, while the potential strategic benefits of the transaction, such as synergy potential and other value creation opportunities, were becoming clearer, additional confirmatory work and diligence still remained. The Neenah board of directors also reviewed again Neenah’s business plan and projections if it were to remain an independent, stand-alone company, and confirmed their continued confidence in Neenah’s strategy as an independent, stand-alone company and the value creation anticipated therefrom for Neenah and its stockholders. During this meeting, the Neenah board of directors held an executive session of the independent directors, at which Neenah’s independent directors further discussed Neenah’s business plan, projections and historical financials, and their perspectives on the potential merger of equals transaction. Following this discussion, Neenah’s independent directors reiterated their support for the continued evaluation of a potential merger of equals transaction with SWM, so that the Neenah board of directors could further assess the transaction.

On February 25, 2022, Dr. Kramer and Ms. Schertell held a telephone call to discuss feedback from the Neenah board of directors meeting. Ms. Schertell indicated that the Neenah board of directors remained generally supportive of the continued evaluation of a potential merger of equals transaction, subject to satisfactory completion of diligence and the synergy analysis from EY. Additionally, Ms. Schertell and Dr. Kramer expressed continued organizational support from both companies in moving forward in a merger of equals transaction.

On March 4, 2022, the Neenah board of directors held a special meeting to discuss the status of the ongoing diligence evaluation and financial analysis for the potential merger of equals transaction. Members of Neenah’s senior management and representatives of Perella Weinberg were also in attendance at this meeting. At that meeting, Mr. Cook provided an update to Neenah’s other independent directors regarding a telephone call he had with a representative from Cravath, Swaine & Moore LLP (which we refer to as “Cravath”) in February 2022, and Neenah’s independent directors expressed their view that the independent directors having their own counsel in a potential significant merger transaction would be helpful. Following discussion, Neenah’s independent directors determined to formally engage Cravath as counsel to Neenah’s independent directors in connection with

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the potential merger of equals transaction. During the meeting, senior management again reviewed an illustrative transaction timeline and transaction workstreams and key diligence workstreams and findings. The Neenah board of directors discussed with representatives of Perella Weinberg and senior management various metrics and how they impacted the relative contribution of each company in a merger of equals transaction, and representatives of Perella Weinberg confirmed that the relative equity valuations and other metrics of the two companies remained consistent with merger of equals transactions. Senior management also presented to the Neenah board of directors on the SWM business, strategic fit, preliminary results of due diligence and market assessments. The Neenah board of directors and senior management also discussed the preliminary synergy analysis by EY and senior management, the potential acceleration of growth and benefits of scale from a potential combination and high level transaction terms for the potential merger of equals transaction, including the composition of the board of directors of the combined company, the role of chair of the board of directors of the combined company, the role of Chief Executive Officer of the combined company and the headquarters, name and operating model of the combined company.

On March 7, 2022, Neenah’s independent directors held a meeting. Representatives of Cravath were present at the meeting. At the meeting, Neenah’s independent directors provided Cravath with a comprehensive summary of the background for the potential merger of equals transaction. Representatives of Cravath discussed with Neenah’s independent directors their fiduciary duties, both in general and in the context of various types of transactions (including merger of equals transactions), as well as how the Neenah board of directors might evaluate the potential transaction with SWM. Representatives of Cravath also discussed with Neenah’s independent directors typical elements of merger of equals transactions. Neenah’s independent directors then discussed the potential governance structure of the combined company, including the role of Chief Executive Officer of the combined company. As part of this discussion, Neenah’s independent directors again expressed their view that, if the two companies ultimately determined to move forward with the potential combination, Ms. Schertell should likely continue to play an integral role as Chief Executive Officer of the combined company, given their confidence in Ms. Schertell and her ability to unlock the potential benefits of the potential combination. After discussion, Neenah’s independent directors determined to further discuss the Chief Executive Officer role and other governance aspects of the combined company at subsequent meetings, once additional financial and operational diligence had been completed and there was greater clarity regarding the potential combined company. Neenah’s independent directors then discussed potential terms and next steps for the potential merger of equals transaction between SWM and Neenah, including with respect to the completion of diligence and negotiation of definitive transaction documentation.

On March 10, 2022, the Neenah board of directors held a special meeting to discuss the status of the ongoing diligence evaluation and financial analysis for the potential merger of equals transaction. Members of Neenah’s senior management and representatives of Perella Weinberg were also in attendance. At this meeting, Ms. Schertell reviewed an updated illustrative transaction timeline and key workstreams. Ms. Schertell and other senior management gave an update with respect to the status of the diligence evaluation of SWM and the potential business combination between Neenah and SWM, confirming that no material issues had been identified. Perella Weinberg and Neenah’s senior management team then reviewed a preliminary set of synergy estimates from the EY analysis, merger of equals exchange ratio calculations and considerations, comparisons to “hold value” estimates, an early view of SWM’s environmental, social and governance profile, and an illustrative business structure for the proposed combined company. Perella Weinberg and senior management also reviewed Neenah’s business plan and projections if it were to remain an independent, stand-alone company and the valuation implied by such plan and projections, including in light of changes since the Neenah board of directors had last considered such plan and projections. The Neenah board of directors again discussed with representatives of Perella Weinberg and senior management various metrics and how they impacted the relative contribution of each company in a merger of equals transaction. In addition, the Neenah board of directors discussed with senior management the strategic fit, preliminary diligence results, and the potential acceleration of growth and benefits of scale from a potential combination. After discussion, the Neenah board of directors agreed that the merger of equals transaction between SWM and Neenah continued to represent an attractive opportunity to create value for Neenah and its stockholders above that which was expected if Neenah remained an

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independent, stand-alone company. The Neenah board of directors directed senior management to execute a formal engagement letter with Perella Weinberg to confirm Perella Weinberg’s engagement as Neenah’s financial advisor in connection with the potential merger of equals transaction. Perella Weinberg was selected due to Perella Weinberg’s knowledge of the business and affairs of Neenah, including from Neenah’s prior experiences working with Perella Weinberg on strategic transactions and the board of directors’ belief that Perella Weinberg had extensive experience advising companies in the industry, as well as significant experience providing strategic and financial advisory services in comparable merger of equals transactions.

On March 11, 2022, Neenah formally entered into an engagement letter with Perella Weinberg, confirming Perella Weinberg’s engagement as Neenah’s financial advisor in connection with the potential merger of equals transaction.

Throughout February and early-to-mid-March 2022, senior management and advisors of both Neenah and SWM continued their respective diligence evaluations based on publicly-available information. On March 11, 2022, the parties opened another virtual dataroom, which was populated with non-public due diligence materials of each party in response to diligence request lists that were prepared by the parties and their respective advisors. During this time, senior management of each party responded to the due diligence requests of the other party and its respective advisors by uploading responsive documents in the virtual dataroom, providing written responses and participating in due diligence calls.

Following the opening of the virtual dataroom, throughout February and March, SWM’s senior management met periodically with representatives of King & Spalding LLP (which we refer to as “King & Spalding”), SWM’s legal advisor, to review transaction timelines, review and respond to Neenah’s open diligence requests, review and supplement SWM’s open diligence requests, review and discuss preliminary legal diligence findings and discuss structural considerations for a potential transaction. During this period, Neenah’s senior management also met periodically with representatives from BCLP to review and discuss preliminary diligence findings and supplemental diligence requests, the proposed structure for the potential transaction, transaction timelines, and the process generally.

On March 14, 2022, Dr. Kramer and Ms. Schertell held a telephone call to discuss impressions of the EY synergies analysis resulting from the clean room diligence evaluation. Dr. Kramer and Ms. Schertell agreed that significant synergy potential and strategic logic had been detailed in the EY report. Dr. Kramer and Ms. Schertell planned to meet in person on March 17, 2022, after SWM’s and Neenah’s respective board of directors meetings (on March 15 and March 16, respectively), together with Dr. Rogers and Mr. Cook, along with Dr. Kimberly Ritrievi, SWM’s Audit Committee chair, to discuss a potential path forward in the event that both companies’ boards of directors approved proceeding with the negotiation of transaction terms and definitive transaction agreements.

On March 14 and March 15, 2022, Ms. Schertell and Dr. Kramer held telephone calls during which they discussed potential cost synergies that could be achievable in the transaction, as well as how the complementary portfolios and business strategies of SWM and Neenah could position the combined company to better serve customers and provide more flexibility to both companies’ profiles. Ms. Schertell and Dr. Kramer also discussed possible approaches to calculating a fixed exchange ratio for the proposed merger of equals transaction, with both parties acknowledging that any exchange ratio should be based on average valuation metrics over an appropriate period of time rather than valuation metrics as of or immediately prior to a specific date. They also continued discussions of potential governance structures of the combined company, including the composition and size of the board of directors of the combined company, the headquarters of the combined company and whether the combined company would change its name. Both Ms. Schertell and Dr. Kramer agreed to continue to discuss the specifics regarding governance of the combined company, along with the various other transaction considerations, with their respective boards of directors.