Civista Bancshares (CIVB) S-4/ARegistration of securities issued in business combination transactions (amended)

As filed with the Securities and Exchange Commission on April 18, 2022

Registration No. 333-264111

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

Civista Bancshares, Inc.

(Exact name of Registrant as specified in its charter)

100 East Water Street

Sandusky, Ohio 44870

(419) 625-4121

(Address, including zip code, and telephone number, including area code, of Registrant’s principal executive offices)

Lance A. Morrsion, Esq.

Civista Bancshares, Inc.

100 East Water Street

Sandusky, Ohio 44870

(419) 627-4530

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate date of commencement of proposed sale of the securities to the public: As soon as practicable after the effective date of this Registration Statement.

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, 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 or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer,” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

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 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 or until the Registration Statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to Section 8(a), may determine.

THE INFORMATION IN THIS PROXY STATEMENT/PROSPECTUS IS NOT COMPLETE AND MAY BE CHANGED. A REGISTRATION STATEMENT RELATING TO THESE SECURITIES HAS BEEN FILED WITH THE SECURITIES AND EXCHANGE COMMISSION. WE MAY NOT ISSUE THESE SECURITIES UNTIL THE REGISTRATION STATEMENT IS EFFECTIVE. THIS PROXY STATEMENT/PROSPECTUS IS NOT AN OFFER TO SELL THESE SECURITIES AND IT IS NOT SOLICITING AN OFFER TO BUY THESE SECURITIES IN ANY STATE WHERE THE OFFER OR SALE IS NOT PERMITTED.

PRELIMINARY PROXY STATEMENT/PROSPECTUS

DATED APRIL 18, 2022 SUBJECT TO COMPLETION

To the Shareholders of Comunibanc Corp.

MERGER PROPOSAL—YOUR VOTE IS VERY IMPORTANT

Civista Bancshares, Inc. (“Civista”) and Comunibanc Corp. (“Comunibanc”), have entered into an Agreement and Plan of Merger dated as of January 10, 2022 (the “Merger Agreement”), which provides for the merger of Comunibanc with and into Civista, with Civista being the surviving entity (the “Merger”). Consummation of the Merger is subject to certain conditions, including, but not limited to, obtaining the requisite vote of the shareholders of Comunibanc and the approval of the Merger by various regulatory agencies.

The proposed Merger will bring together two customer-focused organizations with deep commitments to the communities they serve. Both Civista and Comunibanc share a community banking philosophy that is focused on customers and is built upon providing exceptional advice and service to its customers. Overall, the Merger will benefit Comunibanc’s customers by providing them access to a broader array of products and services.

Under the terms of the Merger Agreement, shareholders of Comunibanc will be entitled to receive from Civista, after the Merger is completed, merger consideration payable in the form of Civista common shares and cash to be calculated as set forth in the Merger Agreement. At the effective time of the Merger, each outstanding common share of Comunibanc would be converted into the right to receive: (i) $30.13 in cash; and 1.1888 common shares of Civista. Holders of Civista common shares will continue to own their existing Civista common shares. Civista common shares are traded on the Nasdaq Capital Market^® under the symbol “CIVB.” On January 10, 2022 the date of execution of the Merger Agreement, the closing price of Civista’s common shares was $25.12 per share. On April 14, 2022, the closing price of Civista common shares was $22.63 per share. Comunibanc common shares are quoted on the OTC Pink Open Market under the symbol “CBCZ.” On January 10, 2022, the date of execution of the Merger Agreement, the closing price of Comunibanc common shares was $37.90 per share. On April 14, 2022, the closing price of Comunibanc common shares was $56.53 per share.

Because the Exchange Ratio is fixed (except for customary anti-dilution adjustments and certain price protection provisions as described in the Merger Agreement), when you receive Civista common shares as a portion of the consideration for your common shares of Comunibanc, the implied value of the common share consideration that you will receive will depend on the market price of Civista’s common shares when you receive your Civista common shares. The value of the Civista common shares at the time of completion of the Merger could be greater than, less than or the same as the value of Civista common shares on the date of this proxy statement/prospectus. We urge you to obtain current market quotations of Civista common shares and Comunibanc common shares.

Civista will not issue any fractional common shares in connection with the Merger. Instead, each holder of Comunibanc common shares who would otherwise be entitled to receive a fraction of a Civista common share (after taking into account all Comunibanc common shares owned by such holder at the effective time of the Merger) will receive cash, without interest, (rounded to the nearest cent) equal to the Civista fractional common share to which such holder would otherwise be entitled, multiplied by (i) the average of the closing-sale prices of Civista common shares on the NASDAQ Capital Market as reported by The Wall Street Journal for the five (5) consecutive full trading days ending on the trading day preceding the closing date by (ii) the fraction of a share (rounded to the nearest one-thousandth when expressed in decimal form) of Civista common shares which such holder would otherwise be entitled to receive.

Comunibanc will hold a special meeting of its shareholders to vote on the adoption and approval of the Merger Agreement. The special meeting of Comunibanc shareholders will be held at 2 p.m., Eastern Daylight Savings Time, on June 10, 2022, at the Main Office of The Henry County Bank, 122 E. Washington Street, Napoleon, Ohio 43545.

This document is a proxy statement that Comunibanc is using to solicit proxies for use at its special meeting of shareholders to be held on June 10, 2022, to vote on the adoption and approval of the Merger Agreement. It is also a prospectus relating to Civista’s offer and sale of its common shares in connection with the Merger. This proxy statement/prospectus describes the special meeting, the Merger proposal and other related matters.

The board of directors of Comunibanc unanimously approved the Merger Agreement and the transactions contemplated thereby, including the Merger, and recommend that shareholders vote “FOR” each of the proposals to be considered at the special meeting.

You are encouraged to read this document, including the materials incorporated by reference into this document, carefully. In particular, you should read the “RISK FACTORS” section beginning on page 21 for a discussion of the risks related to the Merger and owning Civista common shares after the Merger.

Whether or not you plan to attend Comunibanc’s special meeting, the Comunibanc board urges you to vote by completing, signing and returning the enclosed proxy card in the enclosed postage-paid envelope.

Not voting by proxy or at the Comunibanc special meeting will have the same effect as voting against the adoption and approval of the Merger Agreement. The Comunibanc board urges you to read carefully this proxy statement/prospectus, which contains a detailed description of Comunibanc’s special meeting, the Merger proposal, Civista’s common shares to be issued in the Merger and other related matters.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of Civista common shares to be issued in the Merger or determined if this proxy statement/prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The securities to be issued in connection with the Merger described in this proxy statement/prospectus are not savings accounts, deposit accounts or other obligations of any bank or savings association and are not insured by the Federal Deposit Insurance Corporation or any other federal or state governmental agency.

This proxy statement/prospectus is dated April 18, 2022, and it

is first being mailed to Comunibanc shareholders on or about April 25, 2022. 

Comunibanc Corp.

Notice of Special Meeting of Shareholders

To be held at 2 p.m., Eastern Daylight Savings Time, on June 10, 2022, at

the Main Office of The Henry County Bank located at 122 E. Washington Street, Napoleon, Ohio 43545

To the Shareholders of Comunibanc Corp.:

Notice is hereby given that a special meeting of the shareholders of Comunibanc Corp. (“Comunibanc”) will be held at 2 p.m., Eastern Daylight Savings Time, on June 10, 2022, at the Main Office of The Henry County Bank, 122 E. Washington Street, Napoleon, Ohio 43545, for the purpose of considering and voting on the following matters:

Holders of record of Comunibanc common shares at the close of business on April 18, 2022, the record date, are entitled to notice of and to vote at the special meeting and any adjournment or postponement of the special meeting. The affirmative vote of the holders of at least a majority of Comunibanc’s shares is required to adopt and approve the Agreement and Plan of Merger.

A proxy statement/prospectus and proxy card for the special meeting are enclosed. A copy of the Agreement and Plan of Merger is attached as Annex A to the proxy statement/prospectus.

Your vote is very important, regardless of the number of Comunibanc common shares you own. Please vote as soon as possible to make sure that your common shares are represented at the special meeting. If you are a holder of record, you may cast your vote in person at the special meeting or, to ensure that your Comunibanc common shares are represented at the special meeting, you may vote your shares by completing, signing and returning the enclosed proxy card. If your shares are held in a stock brokerage account or by a bank or other nominee (in “street name”), please follow the voting instructions provided by your broker, bank or nominee.

The Comunibanc board of directors unanimously recommends that you vote (1) “FOR” the adoption and approval of the Agreement and Plan of Merger, and (2) “FOR” the proposal to adjourn the special meeting, if necessary, to solicit additional proxies.

By Order of the Board of Directors,

William L. Wendt

President & Chief Executive Officer

Comunibanc Corp.

April 18, 2022

WHERE YOU CAN FIND MORE INFORMATION

Civista Bancshares, Inc. (“Civista”) is a publicly traded company that files annual, quarterly and other reports, proxy statements and other business and financial information with the Securities and Exchange Commission (the “SEC”). The public filings are available to the public from the SEC’s website at www.sec.gov. You may request a copy of Civista’s filings with the SEC (excluding exhibits) at no cost by contacting Civista at the address and/or telephone number below. Certain information filed by Civista with the SEC is also available, without charge, through Civista’s website at www.civb.com under the “Investor Relations” section.

Civista has filed with the SEC a registration statement on Form S-4 to register its common shares to be issued to Comunibanc shareholders as part of the merger consideration. This document is a part of that registration statement. As permitted by SEC rules, this document does not contain all of the information included in the registration statement or in the exhibits or schedules to the registration statement. You may read and request a copy of the registration statement, including any amendments, schedules and exhibits at the addresses set forth below. Statements contained in this document as to the contents of any contract or other documents referred to in this document are not necessarily complete. In each case, you should refer to the copy of the applicable contract or other document filed as an exhibit to the registration statement. This proxy statement/prospectus incorporates by reference important business and financial information about Civista from documents filed with or furnished to the SEC that are not included in or delivered with this proxy statement/prospectus. See “INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE” on page 68. These documents are available, without charge, to you upon written or oral request at the Civista address and telephone number listed below:

Civista Bancshares, Inc.

100 East Water Street

Sandusky, Ohio 44870

Attention: Investor Relations

(419) 625-4121

Additional information about Comunibanc may be obtained by contacting Comunibanc Corp., c/o The Henry County Bank, 122 E. Washington Street, Napoleon, Ohio 43545, (419) 599-1065.

To obtain timely delivery of these documents, you must request the information no later than                , 2022 in order to receive them before the Comunibanc special meeting.

Civista common shares are traded on the Nasdaq Capital Market^® under the symbol “CIVB.” Comunibanc common shares are quoted on the OTC Pink Open Market under the symbol “CBCZ.”

Civista has not authorized anyone to provide you with any information other than the information included in this document and documents which are incorporated by reference. If anyone provides you with different or inconsistent information, you should not rely on it. You should assume that the information appearing in this document and the documents incorporated by reference are accurate only as of their respective dates. Civista’s business, financial condition, results of operations and prospects may have changed since those dates.

TABLE OF CONTENTS

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QUESTIONS AND ANSWERS ABOUT THE MERGER AND THE SPECIAL MEETING

The following are answers to certain questions that you may have regarding the special meeting. You are urged to read carefully the remainder of this document because the information in this section may not provide all the information that might be important to you in determining how to vote. Additional important information is also contained in the appendices to, and the documents incorporated by reference in, this document.

Comunibanc is holding a special meeting of holders of Comunibanc common shares (the “Comunibanc Special Meeting”) to obtain approval of the Comunibanc Merger proposal. Holders of Comunibanc common shares are entitled to dissenter’s rights. This document is also a prospectus that is being delivered to holders of Comunibanc common shares because, in connection with the merger, Civista is offering Civista common shares to holders of Comunibanc’s common shares as part of the Merger Consideration.

This proxy statement/prospectus contains important information about the Merger and the special meeting of the shareholders of Comunibanc, and you should read it carefully. The enclosed proxy materials allow you to vote your Comunibanc common shares without attending the special meeting. Your vote is important, and we encourage you to submit your proxy as soon as possible.

Civista believes that the Merger is in the best interests of its shareholders and will benefit Civista and its shareholders by enabling Civista to further expand into the Northwest Ohio market strengthening the

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competitive position of the combined organization. Furthermore, Civista believes its increased asset size after the Merger will create additional economies of scale and provide opportunities for asset and earnings growth in an extremely competitive banking environment. To review Civista’s reasons for the Merger in more detail, see “THE MERGER—Civista’s Reasons for the Merger” on page 36 of this proxy statement/prospectus.

Civista will not issue any fractional common shares in connection with the Merger. Instead, each holder of Comunibanc common shares who would otherwise be entitled to receive a fraction of a Civista common share (after taking into account all Comunibanc common shares owned by such holder at the effective time of the Merger) will receive cash, without interest, in an amount (rounded to the nearest cent) equal to the Civista fractional common share to which such holder would otherwise be entitled, multiplied by (i) the average of the closing-sale prices of Civista common shares on the Nasdaq Capital Market^® as reported by The Wall Street Journal for the five (5) consecutive full trading days ending on the trading day preceding the closing date by (ii) the fraction of a share (rounded to the nearest one-thousandth when expressed in decimal form) of Civista common shares which such holder would otherwise be entitled to receive.

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THE TAX CONSEQUENCES OF THE MERGER WILL DEPEND ON THE FACTS OF YOUR OWN SITUATION. YOU SHOULD CONSULT YOUR OWN TAX ADVISOR AS TO THE SPECIFIC TAX CONSEQUENCES OF THE MERGER TO YOU IN YOUR PARTICULAR CIRCUMSTANCES.

Even if you plan to attend the Comunibanc special meeting, Comunibanc recommends that you vote your shares in advance so that your vote will be counted if you later decide not to or become unable to attend the special meeting. See “How do I vote my common shares of Comunibanc?” below.

Each holder of Comunibanc common shares is entitled to cast one (1) vote on each matter properly brought before the Comunibanc special meeting for each Comunibanc common share that such holder owned of record as of the record date. Attendance at the Comunibanc special meeting is not required to vote. Whether or not you attend the Comunibanc special meeting, the Comunibanc board of directors urges you to promptly submit your voting instructions by signing and returning the enclosed proxy card in the postage-paid envelope provided, so that your shares will be represented at the Comunibanc special meeting. If you return your properly executed proxy card, prior to the special meeting and do not revoke it prior to its use, your proxies will be voted at the special meeting or, if appropriate, at any adjournment of the special

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meeting. Comunibanc’s common shares will be voted as specified on the proxy card or, in the absence of specific instructions to the contrary, will be voted “FOR” the adoption and approval of the Merger Agreement, and, “FOR” the approval of the adjournment of the special meeting, if necessary, to solicit additional proxies.

If you are a record holder of your shares and you have returned a properly executed proxy card, you may revoke it or change it at any time before a vote is taken at the special meeting by:

If you hold Comunibanc common shares in the name of a broker, bank or other nominee, please see the discussion below regarding shares held in “street name.”

Shares in “street name.” If your Comunibanc common shares are held in street name, you should have received a notice of internet availability of proxy materials or voting instructions from the broker, bank or other nominee holding your common shares. You should follow the instructions in the notice of internet availability of proxy materials or voting instructions provided by your broker or other nominee in order to instruct your broker or other nominee on how to vote your common shares. The availability of telephone and internet voting will depend on the voting process of your broker or other nominee. If you do not instruct your bank or broker how to vote in the, no votes will be cast on your behalf.

Even if you plan to attend the Comunibanc special meeting, Comunibanc recommends that you vote your shares in advance so that your vote will be counted if you later decide not to or become unable to attend the special meeting. See “How do I vote my common shares of Comunibanc?” above. Additional information on attending the special meeting can be found under the section entitled “The Special Meeting of Shareholders of Comunibanc” on page 27.

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Assuming a quorum is present, if you are a Comunibanc shareholder and you do not instruct your broker, bank or other nominee on how to vote your shares or you abstain from voting,

Your attendance at the special meeting will not, by itself, revoke your proxy.

If you hold your common shares in “street name” and you have instructed your broker, bank or nominee to vote your common shares, you must follow directions received from your broker, bank or nominee to change your vote.

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Comunibanc Corp.

Attention: William L. Wendt, President

122 E. Washington Street

Napoleon, Ohio 43545

(419) 599-1065

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SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA FOR CIVISTA

The following table summarizes financial results achieved by Civista for the periods and at the dates indicated and should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” Civista’s Consolidated Financial Statements and the notes to the Consolidated Financial Statements contained in reports that Civista has previously filed with the SEC. Historical financial information for Civista can be found in its Annual Report on Form 10-K for the fiscal year ended December 31, 2021. The information at and for the three months ended December 31, 2021 and 2020 is unaudited. However, in the opinion of management of Civista all adjustments, consisting of normal recurring adjustments necessary for a fair presentation of the results of operations for the unaudited periods have been made. The selected operating data presented below for the three months ended December 31, 2021 and 2020 are not necessarily indicative of the results that may be expected for future periods. See “WHERE YOU CAN FIND MORE INFORMATION” in the forepart of this document for instructions on how to obtain the information that has been incorporated by reference. You should not assume the results of operations for past periods noted below indicate results for any future period.

The information below has been derived from Civista’s Consolidated Financial Statements.

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UNAUDITED COMPARATIVE PER SHARE DATA

The following table sets forth for Civista and Comunibanc certain historical, pro forma and pro forma-equivalent per share financial information as of and for the year ended December 31, 2021 and unaudited pro forma financial information as of and for the three months ended December 31, 2021. The information in the table below, in part, is derived from and should be read together with the historical Consolidated Financial Statements of Civista that are incorporated by reference in this proxy statement/prospectus. The unaudited pro forma information, while helpful in illustrating the financial characteristics of the combined company under one set of assumptions, does not reflect certain anticipated costs and benefits of the Merger and, accordingly, does not attempt to predict or suggest future results. It also does not necessarily reflect what the historical results of the combined company would have been had the Merger been consummated at the beginning of the periods presented. The pro forma data gives effect to the Merger and is based on numerous assumptions and estimates. The pro forma combined per share data and Comunibanc pro forma per share data are prepared assuming a maximum of 984,926 common shares will be issued in the Merger. See “THE MERGER AGREEMENT—Merger Consideration” on page 51.

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MARKET PRICE AND DIVIDEND INFORMATION

Civista’s common shares are listed and trade on the Nasdaq Capital Market^® under the symbol “CIVB”. As of April 14, 2022 there were 14,724,189 Civista common shares outstanding. Civista has approximately 1499 shareholders of record.

Comunibanc’s common shares are quoted on the OTC Pink Open Market under the symbol “CBCZ,” however, the shares do not have an active trading market and are not traded frequently. As of April 18, 2022 there were 828,504 Comunibanc common shares outstanding, which were held by 384 holders of record.

The information presented in the following table reflects the last reported sale prices per share of Civista common shares and Comunibanc common shares as of January 10, 2022, the last trading day preceding our public announcement of the Merger, and April 14, 2022, the last practicable day for which information was available prior to the date of this proxy statement/prospectus. The table also presents the implied value of Comunibanc common shares based on those prices for Civista’s common shares and the 1.1888 fixed exchange ratio. The implied value reflected below includes the $30.13 in cash consideration that will be paid in the Merger. No assurance can be given of what the market price of Civista’s common shares will be if and when the Merger is completed.

The following table lists the high and low prices per share for Civista common shares and Comunibanc common shares and the cash dividends declared by each company for the periods indicated.

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This proxy statement/prospectus contains certain forward-looking statements, including, but not limited to, certain plans, expectations, goals, projections, and statements about the benefits of the proposed merger, the plans, objectives, expectations and intentions of Civista and Comunibanc, the expected timing of completion of the Merger, and other statements that are not historical facts. Such statements are subject to numerous assumptions, risks, and uncertainties. Statements that do not describe historical or current facts, including statements about beliefs and expectations, are forward-looking statements. Forward-looking statements may be identified by words such as expect, anticipate, continue, remain, believe, intend, estimate, plan, target, goal, or similar expressions, or future or conditional verbs such as will, may, might, should, would, could, or similar variations. The forward-looking statements are intended to be subject to the safe harbor provided by Section 27A of the Securities Act, Section 21E of the Exchange Act, and the Private Securities Litigation Reform Act of 1995 (“Reform Act”), notwithstanding that such statements are not specifically identified.

While there is no assurance that any list of risks and uncertainties or risk factors is complete, below are certain factors, in addition to the factors relating to the Merger discussed under the caption “RISK FACTORS” beginning on page 21 and the factors previously disclosed in Civista’s reports filed with the SEC, which could cause actual results to differ materially from those contained or implied in the forward-looking statements:

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In addition, certain statements may be contained in the future filings of Civista with the SEC, in press releases and in oral and written statements made by or with the approval of Civista that are not statements of historical fact and constitute forward-looking statements within the meaning of the Reform Act. Examples of forward-looking statements include, but are not limited to:

You are cautioned not to place undue reliance on the forward-looking statements, which speak only as of the date of this proxy statement/prospectus or the dates of the documents incorporated by reference in this proxy statement/prospectus. 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 worse than projected and such differences could be material. Given these uncertainties, we caution you not to place 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. Except as required by applicable law, neither Civista nor Comunibanc undertakes to update these forward-looking statements to reflect facts, circumstances, assumptions or events that occur after the date the forward-looking statements are made.

Additional information about factors that could cause actual results to differ materially from those described in the forward-looking statements, are discussed in the reports that Civista has filed with the SEC as described under “Where You Can Find More Information” in the forepart of this document.

Civista and Comunibanc expressly qualify in their entirety all forward-looking statements attributable to either of them, or any person acting on their behalf, by reference to the cautionary statements contained or referred to in this proxy statement/prospectus.

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RISK FACTORS

In addition to general investment risks and the other information contained in or incorporated by reference into this proxy statement/prospectus, including the matters addressed under the section “CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS” on page 19, you should carefully consider the following risk factors in deciding how to vote for the proposals presented in this proxy statement/prospectus. You should also consider the other information in this proxy statement/prospectus and the other documents incorporated by reference into this proxy statement/prospectus. See “WHERE YOU CAN FIND MORE INFORMATION” in the forepart of this document.

An investment by Comunibanc shareholders in Civista common shares as a result of the exchange of shares of Civista common shares for Comunibanc common shares in the Merger involves certain risks. In addition, Civista discusses certain other material risks connected with the ownership of Civista common shares and with Civista’s business under the caption “Risk Factors” appearing in its Annual Report on Form 10-K most recently filed with the SEC and may include additional or updated disclosures of such material risks in its subsequent Quarterly Reports on Form 10-Q and Current Reports on Form 8-K that Civista has filed with the SEC or may file with the SEC after the date of this proxy statement/prospectus, of which such reports are or will be incorporated by reference in this proxy statement/prospectus.

Holders of Comunibanc common shares should carefully read and consider all of these risks and all other information contained in this proxy statement/prospectus, including the discussions of risk factors included in the documents incorporated by reference in this proxy statement/prospectus, in deciding whether to vote for approval of the various proposals for which they may be entitled to vote at the Comunibanc Special Meeting described herein. The risks described in this proxy statement/prospectus and in those documents incorporated by reference may adversely affect the value of Civista common shares that you, as an existing holder of Comunibanc common shares, will hold upon consummation of the Merger, and could result in a significant decline in the value of Civista common shares and cause the current holders of Civista common shares and/or the holders of Comunibanc common shares to lose all or part of the value of their respective investments in Civista common shares.

Risks Related to the Merger

Because the market price of Civista common shares may fluctuate, holders of Comunibanc common shares cannot be certain of the market value of the Merger Consideration they will receive.

Under the terms of the Merger Agreement, all of the Comunibanc common shares exchanged in the Merger will be exchanged for a combination of Civista common shares and cash. The cash portion of the Merger consideration is fixed at $30.13 per share, and the common share portion is fixed at 1.1888 Civista common shares for each common share of Comunibanc exchanged.

Civista will not issue any fractional shares of common shares in connection with the Merger. Instead, each holder of Comunibanc common shares who would otherwise be entitled to receive a fraction of a Civista common share (after taking into account all shares of Comunibanc common shares owned by such holder at the effective time of the Merger) will receive cash, without interest, in an amount equal to the Civista fractional common share to which such holder would otherwise be entitled to multiplied by the average of the closing sale price of Civista common shares on the Nasdaq Capital Market for the five (5) consecutive full trading days immediately preceding the effective date of the Merger.

Any change in the market price of Civista common shares prior to the completion of the Merger will affect the market value of the Merger Consideration that Comunibanc shareholders will receive following completion of the Merger. Stock price changes may result from a variety of factors that are beyond the control of Civista and

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Comunibanc, including but not limited to general market and economic conditions, impacts and disruptions resulting from the ongoing COVID-19 pandemic, changes in their respective businesses, operations and prospects, and regulatory considerations. Therefore, at the time of the Comunibanc special meeting, Comunibanc shareholders will not know the precise market value of the consideration they will receive at the effective time of the Merger. Comunibanc shareholders should obtain current sale prices for Civista common shares before voting their shares at the Comunibanc special meeting.

Comunibanc has the right to terminate the Merger Agreement if, prior to the effective time of the Merger and during the time period specified in the Merger Agreement, if the market value of Civista’s common shares drops below certain pre-determined thresholds while the Nasdaq Bank Index does not; provided, however, that Civista will have the right to prevent Comunibanc’s termination by increasing the Exchange Ratio for the stock portion of the Merger consideration pursuant to a formula set forth in the Merger Agreement.

The market price of Civista common shares after the Merger may be affected by factors different from those affecting the shares of Comunibanc common shares or Civista common shares currently.

In the Merger, holders of Comunibanc common shares will become holders of Civista common shares. Although similar in some respects, Civista’s business does differ from that of Comunibanc. Accordingly, the results of operations of the combined company and the market price of Civista’s common shares after the completion of the Merger may be affected by factors different from those currently affecting the independent results of operations of each of Civista and Comunibanc. For a discussion of the businesses of Civista and Comunibanc and of certain factors to consider in connection with those businesses, see the documents incorporated by reference in this proxy statement/prospectus and referred to under “Where You Can Find More Information” in the forepart of this document.

Civista could experience difficulties in managing its growth and effectively integrating the operations of Comunibanc and the Subsidiary Bank.

The earnings, financial condition and prospects of Civista after the Merger will depend in part on Civista’s ability to integrate successfully the operations of Comunibanc and the Subsidiary Bank and to continue to implement its own business plan. Civista may not be able to fully achieve the strategic objectives and projected operating efficiencies anticipated in the Merger. The costs or difficulties relating to the integration of Comunibanc and the Subsidiary Bank with the Civista organization may be greater than expected or the cost savings from any anticipated economies of scale of the combined organization may be lower or take longer to realize than expected. Inherent uncertainties exist in integrating the operations of any acquired entity, and Civista may encounter difficulties, including matters such as loss of key employees and customers, and the disruption of its ongoing business or possible inconsistencies in standards, controls, procedures and policies, among others. These factors could contribute to Civista not fully achieving the expected benefits from the Merger.

The Merger Agreement limits Comunibanc’s ability to pursue alternatives to the Merger with Civista which may discourage other acquirers from offering a higher valued transaction to Comunibanc and may, therefore, result in less value for the Comunibanc shareholders.

The Merger Agreement contains a provision that, subject to certain limited exceptions, prohibits Comunibanc from soliciting, negotiating, or providing confidential information to any third party relating to any competing proposal to acquire Comunibanc or the Subsidiary Bank.

In addition, if the Merger Agreement is terminated by Comunibanc under certain circumstances involving alternative acquisition proposals, Comunibanc may be required to pay a termination fee to Civista equal to $2,008,000 million. The requirement that Comunibanc make such a payment could discourage another company from making a competing proposal.

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The fairness opinion of Comunibanc’s financial advisor does not reflect changes in circumstances subsequent to the date of such opinion.

The Comunibanc board of directors received an opinion, dated January 10, 2022, from ProBank Austin, its financial advisor, as to the fairness of the Merger Consideration, including the Exchange Ratio, from a financial point of view, as of the date of each such opinion. Subsequent changes in the operation and prospects of Comunibanc or Civista, general market and economic conditions and other factors that may be beyond the control of Comunibanc or Civista may significantly alter the value of Comunibanc or Civista or the prices of the Comunibanc common shares or Civista common shares by the time the Merger is completed. The opinion does not address the fairness of the Merger Consideration, including the Exchange Ratio, from a financial point of view, at the time the Merger is completed, or as of any other date other than the date of such opinion. The opinion of Comunibanc’s financial advisor is attached as Annex C to this proxy statement/prospectus. For a description of the opinion, see “THE MERGER—Opinion of Comunibanc’s Financial Advisor” on page 35 of this proxy statement/prospectus. 

Civista and Comunibanc shareholders will have a reduced ownership and voting interest after the Merger and will exercise less influence over management of the combined organization.

The Merger will dilute the ownership position of Civista shareholders and result in Comunibanc shareholders having an ownership stake in the combined company that is smaller than their current stake in Comunibanc. Upon completion of the Merger, we estimate that continuing Civista shareholders will own approximately 93.82% of the issued and outstanding common shares of the combined company, and former Comunibanc shareholders will own approximately 6.18% of the issued and outstanding common shares of the combined company. Consequently, Civista shareholders and Comunibanc shareholders, as a general matter, will have less influence over the management and policies of the combined company after the effective time of the Merger than they currently exercise over the management and policies of Civista and Comunibanc, respectively.

Failure to complete the Merger could negatively impact the value of Comunibanc’s stock and future businesses and financial results of Civista and Comunibanc.

If the Merger is not completed, the ongoing businesses of Civista and Comunibanc may be adversely affected and Civista and Comunibanc will be subject to several risks, including the following:

In addition, if the Merger is not completed, Comunibanc may experience negative reactions from its customers and employees. Employees could resign and obtain other employment as a result of the potential Merger. Comunibanc also could be subject to litigation related to any failure to complete the Merger.

The combined company is expected to incur substantial costs in connection with the related integration which is to occur after completion of the Merger in the fourth quarter of 2022. There are a large number of processes, policies, procedures, operations, technologies and systems that may need to be integrated, including data processing, purchasing, accounting and finance, payroll, compliance, treasury management, branch operations, vendor management, risk management, lines of business, pricing and benefits. While Comunibanc

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and Civista have assumed that a certain level of costs will be incurred, there are many factors beyond their control that could affect the total amount or the timing of the integration costs. Moreover, many of the costs that will be incurred are, by their nature, difficult to estimate accurately. These integration costs may result in the combined company taking charges against earnings following the completion of the merger, and the amount and timing of such charges are uncertain at present.

The Civista common shares to be received by Comunibanc shareholders upon completion of the Merger will have different rights from Comunibanc common shares.

Upon completion of the Merger, Comunibanc shareholders will no longer be shareholders of Comunibanc but will instead become shareholders of Civista, and their rights as shareholders of Civista will continue to be governed by the Ohio Revised Code and by Civista’s Amended Articles of Incorporation and Code of Regulations. The terms of Civista’s Amended Articles of Incorporation and Regulations are in some respects materially different than the terms of Comunibanc’s Amended Articles of Incorporation. See “COMPARISON OF CERTAIN RIGHTS OF COMUNIBANC AND CIVISTA SHAREHOLDERS” on page 64 of this proxy statement/prospectus.

The Merger Agreement subjects Civista and Comunibanc to certain restrictions on their respective business activities prior to the effective time.

The Merger Agreement subjects Civista and Comunibanc to certain restrictions on their respective business activities prior to the effective time. Subject to certain specified exceptions, the Merger Agreement obligates Comunibanc to, and to cause each of its subsidiaries to, conduct its business in the ordinary course in all material respects and use reasonable best efforts to maintain and preserve intact its business organization and advantageous business relationships, and each of Civista and Comunibanc to, and to cause each of its subsidiaries to, take no action that would reasonably be likely to adversely affect or delay the ability of either Civista or Comunibanc obtain any necessary approvals of any regulatory agency or other governmental entity required for the transactions contemplated by the Merger Agreement or to perform its respective covenants and agreements under the Merger Agreement or to consummate the transactions contemplated by the Merger Agreement on a timely basis. These restrictions could prevent Comunibanc from pursuing certain business opportunities that arise prior to the effective time. See the section entitled “THE MERGER AGREEMENT—Comunibanc’s Conduct of Business Pending the Merger” beginning on page 58 and “THE MERGER AGREEMENT—Civista’s Conduct of Business Pending the Merger” beginning on page 62.

The COVID-19 pandemic’s impact on the combined company’s business and operations is uncertain.

The extent to which the continuation of the COVID-19 pandemic or any variant will negatively affect the business, financial condition, liquidity, capital and results of operations of the combined company will depend on future developments, which are highly uncertain and cannot be predicted, including the scope and duration of the COVID-19 pandemic or any variant, the direct and indirect impact of the COVID-19 pandemic or any variant on employees, clients, counterparties and service providers, as well as other market participants, and actions taken by governmental authorities and other third parties in response to the COVID-19 pandemic or any variant. Given the ongoing and dynamic nature of the circumstances, it is difficult to predict the impact of the COVID-19 pandemic on the combined company’s business, and there is no guarantee that efforts by the combined company to address the adverse impacts of the COVID-19 pandemic or any variant will be effective.

Even after the COVID-19 pandemic or any variant has subsided, the combined company may continue to experience adverse impacts to its business as a result of the COVID-19 pandemic’s global economic impact, including reduced availability of credit, adverse impacts on liquidity and the negative financial effects from any recession or depression that may occur.

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Completion of the Merger is subject to many conditions and if these conditions are not satisfied or waived, the Merger will not be completed.

The respective obligations of Civista and Comunibanc to complete the Merger are subject to the fulfillment or written waiver of many conditions, including approval by the requisite vote of Comunibanc shareholders, receipt of requisite regulatory approvals, absence of orders prohibiting completion of the Merger, effectiveness of the registration statement of which this document is a part, approval of the Civista common shares to be issued to Comunibanc for listing on the Nasdaq, the continued accuracy of the representations and warranties by both parties, and the performance by both parties of their covenants and agreements. See “THE MERGER AGREEMENT—Conditions to Consummation of the Merger” on page 55 of this proxy statement/prospectus. These conditions to the consummation of the Merger may not be fulfilled and, accordingly, the Merger may not be completed. In addition, if the Merger is not completed by November 30, 2022, either Civista or Comunibanc may have the opportunity to choose not to proceed with the Merger, and the parties can mutually decide to terminate the Merger Agreement at any time, before or after approval by the requisite vote of the Comunibanc shareholders. In addition, Civista or Comunibanc may elect to terminate the Merger Agreement in certain other circumstances. See “THE MERGER AGREEMENT—Termination of the Merger Agreement” on page 62 of this proxy statement/prospectus for a fuller description of these circumstances.

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

Before the Merger and the Civista Bank Merger may be completed, various approvals, consents and non-objections must be obtained from the Federal Reserve and the ODFI. In determining whether to grant these approvals, these regulatory authorities consider a variety of factors, including the regulatory standing of each party and the factors described under “THE MERGER —Regulatory Approvals Required” beginning on page 42. These approvals could be delayed or not obtained at all, due to a number of factors including any or all of the following: an adverse development in either party’s regulatory standing, or any other factors considered by regulatory authorities in granting such approvals; governmental, political or community group inquiries, investigations or opposition; changes in legislation or the political environment, including as a result of changes of the U.S. executive administration, Congressional leadership and regulatory agency leadership; or impacts and disruptions resulting from the COVID-19 pandemic or any variant. The approvals that are granted may impose terms and 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 the regulatory authorities will not impose any such conditions, limitations, obligations or restrictions or 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 will otherwise reduce the anticipated benefits of the Merger. In addition, there can be no assurance that any such conditions, limitations, obligations or restrictions will not result in the delay or abandonment of the merger. Additionally, the completion of the Merger is conditioned on the absence of certain orders, injunctions or decrees by any governmental entity of competent jurisdiction that would prohibit or make illegal the completion of any of the transactions contemplated by the Merger Agreement. Despite the parties’ commitments to use their reasonable best efforts to respond to any request for information and resolve any objection that may be asserted by any governmental entity with respect to the Merger Agreement, neither Civista, Comunibanc nor Comunibanc’s respective subsidiaries is required under the terms of the Merger Agreement to take any action, or commit to take any action, or agree to any condition or restriction in connection with obtaining these approvals, that would reasonably be likely to have a material adverse effect on the combined company and its subsidiaries, taken as a whole, after giving effect to the Merger. See the section entitled “THE MERGER —Regulatory Approvals Required” beginning on page 42.

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Issuance of shares of Civista common shares in connection with the Merger may adversely affect the market price of Civista common shares.

In connection with the payment of the merger consideration, Civista expects to issue approximately 984,926 shares of Civista common shares to Comunibanc shareholders. The issuance of these new shares of Civista common shares may result in fluctuations in the market price of Civista common shares, including a stock price decrease.

Certain Comunibanc directors and executive officers have interests in the Merger that may differ from the interests of Comunibanc shareholders.

The Comunibanc shareholders should be aware that certain Comunibanc directors and executive officers have interests in the Merger and have arrangements that are different from, or in addition to, those of Comunibanc shareholders generally. The Comunibanc board was aware of these interests and considered these interests, among other matters, when making its decision to approve the merger agreement, and in recommending that Comunibanc shareholders vote in favor of the Comunibanc Merger Agreement proposal and certain related matters and against alternative transactions. For a more complete description of these interests, see the section of this proxy statement/prospectus entitled “INTERESTS OF COMUNIBANC EXECUTIVE OFFICERS AND DIRECTORS IN THE MERGER” beginning on page 43.

If the Merger does not qualify as a tax-free reorganization under Section 368(a) of the Internal Revenue Code, then the Comunibanc shareholders may be required to pay substantial U.S. federal income taxes.

Civista’s and Comunibanc’s obligations to complete the Merger are conditioned upon the receipt of tax opinions from both Civista’s legal counsel, Dinsmore & Shohl LLP, and Comunibanc’s legal counsel, Shumaker, Loop & Kendrick, LLP, dated as of the closing date, to the effect that the Merger will qualify as a reorganization under Section 368(a) of the Internal Revenue the Code (the “Merger Tax Opinions”). The Merger Tax Opinions will be based on, among other things, certain representations and assumptions as to factual matters made by Civista and Comunibanc. The failure of any factual representation or assumption to be true, correct and complete in all material respects could affect the validity of the Merger Tax Opinions. An opinion of counsel represents counsel’s best legal judgment and is not binding on the IRS or the courts, and the IRS or the courts may not agree with the conclusions set forth in the Merger Tax Opinions. In addition, the Merger Tax Opinions will be based on current law, and cannot be relied upon if current law changes with retroactive effect. If the Merger does not qualify as a reorganization under Section 368(a) of the Internal Revenue Code, then the stock consideration received in the Merger would be taxable to the U.S. resident shareholders of Comunibanc and such shareholders would be treated as selling their Comunibanc common shares in a taxable transaction in exchange for Civista common shares and cash received in the Merger, and could as a result recognize taxable income in the Merger with respect to the stock consideration as well as the cash consideration received in the Merger. See “THE MERGER—Material U.S. Federal Income Tax Consequences of the Merger” beginning on page 46 of this proxy statement/prospectus.

Risks Related to Civista’s Business

You should read and consider risk factors specific to Civista’s business that will also affect the combined company after the Merger, described in Civista’s Annual Report on Form 10-K for the fiscal year ended December 31, 2021, as updated by subsequently filed Quarterly Reports on Form 10-Q and Current Reports on Form 8-K, all of which are filed by Civista with the SEC and incorporated by reference into this document. See “INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE” on page 68 of this statement/prospectus.

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THE SPECIAL MEETING OF SHAREHOLDERS OF COMUNIBANC

Time, Date and Place

This proxy statement/prospectus is being provided to Comunibanc shareholders in connection with the solicitation of proxies by the Comunibanc board of directors for use at the special meeting of shareholders to be held at 2 p.m., Eastern Daylight Savings Time, on June 10, 2022, at the Main Office of Henry County Bank, 122 E. Washington Street, Napoleon, Ohio 43545, including any adjournments of the special meeting.

This proxy statement/prospectus is also being furnished by Civista to Comunibanc shareholders as a prospectus in connection with the issuance of Civista common shares upon completion of the Merger.

Matters to be Considered

At the Comunibanc Special Meeting, the shareholders of Comunibanc will be asked to consider and vote upon the following matters:

The board of directors of Comunibanc believes that the Merger with Civista is in the best interests of Comunibanc shareholders and recommends that you vote (1) “FOR” the adoption and approval of the Merger Agreement, and (2) “FOR” the proposal to adjourn the special meeting of Comunibanc shareholders, if necessary, to solicit additional proxies.

Record Date; Shares Outstanding and Entitled to Vote

The board of directors of Comunibanc has fixed the close of business on April 18, 2022, as the record date for determining the Comunibanc shareholders who are entitled to notice of and to vote at the Comunibanc special meeting of shareholders. Only holders of Comunibanc common shares at the close of business on the record date will be entitled to notice of and to vote at the Comunibanc special meeting.

As of the close of business on April 14, 2022, there were 828,504 Comunibanc common shares outstanding and entitled to vote at the special meeting. As of the same date, there were no shares of Comunibanc preferred stock outstanding. The Comunibanc common shares were held of record by approximately          shareholders. Each Comunibanc common share entitles the holder to one vote on all matters properly presented at the special meeting.

Votes Required; Quorum

Under Comunibanc’s Amended Articles of Incorporation, the adoption and approval of the Merger Agreement requires the affirmative vote of the holders of at least a majority of the Comunibanc common shares outstanding and entitled to vote at the special meeting. Approval of an adjournment of the special meeting requires the affirmative vote of the holders of a majority of Comunibanc’s common shares represented, in person or by proxy, at the special meeting. The failure to vote in person or submit valid proxy instructions, broker non-votes and abstentions will have no effect on the voting of on the proposal to adjourn.

As of April 18, 2022, directors of Comunibanc owned an aggregate of 59,382 Comunibanc common shares, an amount equal to approximately 7.17% of the outstanding Comunibanc common shares. All of the directors of Comunibanc entered into a Support Agreement with Civista pursuant to which they agreed, subject to

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certain terms and conditions, to vote all of their shares in favor of the adoption and approval of the Merger Agreement. As of the date of this proxy statement/prospectus, Civista and its directors, executive officers and affiliates beneficially owned no Comunibanc common shares.

Your vote is important. The adoption and approval of the Merger Agreement requires the affirmative vote of the holders of at least a majority of the Comunibanc common shares outstanding and entitled to vote at the Comunibanc special meeting. The proposal on the adjournment of the Comunibanc special meeting, if necessary, to solicit additional proxies requires the affirmative vote of at least a majority of the Comunibanc common shares represented in person or by proxy at the Comunibanc special meeting. Beneficial owners who hold Comunibanc common shares in “street name” through a broker must instruct their broker how to vote their shares of Comunibanc common shares on the adoption and approval of the Merger Agreement. Without specific instructions from the beneficial owners brokers are prohibited from voting such shares. If you fail to return your proxy card or vote in person at the special meeting or if you mark “ABSTAIN” on your proxy card or ballot at the special meeting, or if your Comunibanc common shares are held in “street name” and you fail to instruct your broker how to vote, it will have the same effect as a vote “AGAINST” the adoption and approval of the Merger Agreement, but will have no effect on the adjournment proposal.

A quorum, consisting of the holders of a majority of the outstanding Comunibanc common shares, must be present in person or by proxy at the Comunibanc special meeting before any action, other than the adjournment of the special meeting, can be taken. A properly executed proxy card marked “ABSTAIN” will be counted for purposes of determining whether a quorum is present.

The Comunibanc board of directors does not expect any matter other than the adoption and approval of the Merger Agreement, and if necessary, the approval of the adjournment of the special meeting to solicit additional proxies, to be brought before the Comunibanc special meeting.

Solicitation and Revocation of Proxies

A proxy card accompanies each copy of this proxy statement/prospectus mailed to Comunibanc shareholders. Your proxy is being solicited by the board of directors of Comunibanc. Whether or not you attend the special meeting, the Comunibanc board of directors urges you to promptly submit your proxy by mail by returning your properly executed proxy card as soon as possible. If you timely submit your properly executed proxy card prior to the Comunibanc special meeting and do not revoke it prior to its use, the Comunibanc common shares represented by that proxy card will be voted at the special meeting or, if appropriate, at any adjournment of the special meeting. Comunibanc’s common shares will be voted as specified on the proxy card or, in the absence of specific instructions to the contrary, will be voted “FOR” the adoption and approval of the Merger Agreement, and “FOR” the approval of the adjournment of the special meeting, if necessary, to solicit additional proxies.

If you have returned a properly executed proxy card, you may revoke it at any time before a vote is taken at the special meeting:

Your attendance at the special meeting will not, by itself, revoke your proxy.

If you hold your Comunibanc common shares in “street name” through a broker, bank or other nominee, you must provide your broker, bank or nominee (the record holder of your common shares) with instructions on

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how to vote your common shares. Your broker, bank or other nominee will provide you with a proxy card and voting instructions. If you have instructed your broker, bank or other nominee to vote your common shares, you must follow the directions received from your broker, bank or other nominee to change or revoke your vote.

Cost of Solicitation

Comunibanc will bear its own cost of solicitation of proxies on behalf of the Comunibanc board of directors. Proxies will be solicited by mail, and may be further solicited by additional mailings, personal contact, telephone, facsimile or electronic mail, by directors, officers and employees of Comunibanc, none of whom will receive additional compensation for their solicitation activities. Comunibanc will also pay the standard charges and expenses of brokerage houses, voting trustees, banks, associations and other custodians, nominees and fiduciaries, who are record holders of Comunibanc common shares not beneficially owned by them, for forwarding this proxy statement/prospectus and other proxy solicitation materials to, and obtaining proxies from, the beneficial owners of Comunibanc common shares entitled to vote at the special meeting.

Participants in the ESOP

If you participate in the ESOP, you will receive a vote authorization form for the plan that reflects all shares that you may direct the Trustee to vote on your behalf under the ESOP. Please be aware that the Trustee of the plan may establish a deadline for submitting your voting instructions that is before the time of the Comunibanc special meeting.

Under the terms of the ESOP, each ESOP participant may direct the Trustee how to vote the common shares allocated to his or her account. As all ESOP shares held by the ESOP are allocated to the accounts of participants, the Trustee will vote all the allocated shares held in the ESOP as instructed by the participants to whom they have been allocated, and vote all allocated shares for which timely and complete voting instructions are not received in the same proportion as the shares for which instructions are received.

PROPOSALS SUBMITTED TO COMUNIBANC SHAREHOLDERS

Comunibanc Merger Proposal

As discussed throughout this proxy statement/prospectus, Comunibanc is asking its shareholders to adopt and approve the Merger Agreement. Comunibanc shareholders should carefully read this document in its entirety for more detailed information regarding the Merger Agreement and the Merger. In particular, shareholders are directed to the copy of the Merger Agreement attached as Annex A to this proxy statement/prospectus.     

The board of directors of Comunibanc recommends a vote “FOR” the approval and adoption of the Merger Agreement.

Comunibanc Adjournment Proposal

The Comunibanc special meeting may be adjourned to another time or place, if necessary or appropriate, to permit, among other things, the solicitation of additional proxies if there are insufficient votes at the time of the Comunibanc special meeting to approve and adopt the Merger Agreement. If, at the time of the Comunibanc special meeting, the number of common shares of Comunibanc present or represented and voting in favor of the Merger Agreement proposal is insufficient to approve and adopt the Merger Agreement, Comunibanc intends to move to adjourn the Comunibanc special meeting in order to enable the Comunibanc board of directors to solicit additional proxies for approval of the proposal.

In the Comunibanc adjournment proposal, Comunibanc is asking its shareholders to authorize the holder of any proxy solicited by the Comunibanc board of directors to vote in favor of granting discretionary authority to

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the proxy holders to adjourn the Comunibanc special meeting to another time and place for the purpose of soliciting additional proxies. If the Comunibanc shareholders approve the adjournment proposal, Comunibanc could adjourn the Comunibanc special meeting and any adjourned session of the Comunibanc special meeting and use the additional time to solicit additional proxies, including the solicitation of proxies from Comunibanc shareholders who have previously voted.

The Comunibanc board of directors recommends a vote “FOR” the Comunibanc adjournment proposal.

DISSENTERS’ RIGHTS

Rights of Dissenting Comunibanc Shareholders

Shareholders of Comunibanc entitled to certain dissenters’ rights pursuant to Sections 1701.84(A) and 1701.85 of the OGCL. Section 1701.85 generally provides that shareholders of Comunibanc will not be entitled to such rights without strict compliance with the procedures set forth in Section 1701.85, and failure to take any one of the required steps may result in the termination or waiver of such rights. Specifically, any Comunibanc shareholder who is a record holder of Comunibanc common shares on April 18, 2022, the record date for the Comunibanc special meeting, and whose shares are not voted in favor of the adoption of the Merger Agreement may be entitled to be paid the “fair cash value” of such Comunibanc common shares after the effective time of the Merger.

To be entitled to such payment, a shareholder:

A Comunibanc shareholder’s failure to vote against the adoption and approval of the Merger Agreement will not constitute a waiver of such shareholder’s dissenters’ rights. Any written demand must specify the shareholder’s name and address, the number and class of shares held by him, her or it on the Comunibanc record date, and the amount claimed as the “fair cash value” of such Comunibanc common shares.

See the text of Section 1701.85 of the OGCL attached as Annex B to this proxy statement/prospectus for specific information on the procedures to be followed in exercising dissenters’ rights. Comunibanc is notifying each of the holders of record of its common shares as of April 18, 2022 that dissenters’ rights are available and intends that this proxy statement/prospectus constitutes such notice.

If Comunibanc so requests, dissenting shareholders must submit their share certificates to Comunibanc within 15 days of such request, for endorsement on such certificates by Comunibanc that a demand for appraisal has been made. Failure to comply with such a request will terminate the shareholder’s dissenters’ rights. Any such certificates will be promptly returned to the dissenting shareholders by Comunibanc. If Comunibanc and any dissenting shareholder cannot agree upon the “fair cash value” of Comunibanc common shares, either may, within three months after service of demand by the shareholder, file a petition in the Common Pleas Court of Henry County, Ohio, for a determination of the “fair cash value” of such dissenting shareholder’s Comunibanc common shares. The fair cash value of a Comunibanc common share to which a dissenting shareholder is entitled to under Section 1701.85 will be determined as of the day prior to the special meeting. The court may appoint one or more appraisers to determine the “fair cash value” and, if the court approves the appraisers’ report, judgment will be entered for the “fair cash value,” and the costs of the proceedings, including reasonable compensation of the appraisers, will be assessed or apportioned as the court considers equitable.

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If a Comunibanc shareholder exercises his or her dissenters’ rights under Section 1701.85, all other rights with respect to such shareholder’s Comunibanc common shares will be suspended until Comunibanc purchases the shares, or the right to receive the fair cash value is otherwise terminated. Such rights will be reinstated should the right to receive the fair cash value be terminated other than by the purchase of the shares.

The foregoing description of the procedures to be followed in exercising dissenters’ rights available to holders of Comunibanc common shares pursuant to Section 1701.85 of the OGCL may not be complete and is qualified in its entirety by reference to the full text of Section 1701.85 attached as Annex B to this proxy statement/prospectus. Ensuring perfection of dissenters’ rights can be complicated. The procedural rules are specific and must be followed precisely. A Comunibanc shareholder’s failure to comply with these procedural rules may result in his or her becoming ineligible to pursue dissenters’ rights.

U.S. shareholders should note that dissenting shareholders will recognize gain or loss for federal income tax purposes on cash paid to them in satisfaction of the fair value of their shares, and should consult their tax advisors accordingly. See “THE MERGER—Material U.S. Federal Income Tax Consequences of the Merger” beginning on page 46 of this proxy statement/prospectus.

Failure by any shareholder to follow the complex steps required by the OGCL for properly asserting dissenters’ rights may result in the loss of those rights. If you are considering dissenting from the approval of the Merger Agreement and asserting your dissenters’ rights under the OGCL, you should consult your legal advisor.

THE MERGER

The Proposed Merger

The Merger Agreement provides for the merger of Comunibanc with and into Civista, with Civista as the surviving entity. Thereafter, at a later time specified by Civista Bank in its certificate of merger filed with the Ohio Secretary of State, Henry County Bank will be merged with and into Civista Bank, with Civista Bank surviving the Civista Bank Merger.

The Merger Agreement is attached to this proxy statement/prospectus as Annex A and is incorporated in this proxy statement/prospectus by reference.  You are encouraged to read the Merger Agreement carefully, as it is the legal document that governs the Merger.

Background of the Merger

Comunibanc and Henry County Bank have been considering their strategic alternatives over the past few years. Comunibanc had retained ProBank Austin in 2016 to help develop a strategic plan. Late in 2020, Comunibanc determined it was appropriate to update that strategic plan. Comunibanc retained ProBank Austin in January 2021, to assist Comunibanc in developing that updated strategic plan. At that time the board of directors considered its alternatives and very much favored remaining independent. However, Comunibanc realized that remaining independent would be contingent upon its ability to grow into new markets, significantly increase the size of its loan portfolio, find and retain new lenders and senior management, and create liquidity for its shareholders. A number of meetings were held between Comunibanc management and ProBank Austin over the ensuing months and analysis was conducted in that regard.

As the board was continuing to explore its strategic alternatives, on July 12, 2021, Comunibanc’s board received an unsolicited offer from a larger community bank. The proposal from the other community bank (“Buyer 1”) proposed that Henry County Bank would be run as an affiliate of Buyer 1 with current management remaining in place. The proposed price, while a premium to the then current market price for Comunibanc’s shares, was below the range that ProBank Austin had suggested could be obtained in a sale transaction. The

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board of directors of Comunibanc met as part of a regular board meeting on July 23, 2021, to consider the unsolicited offer. Richard F. Maroney, Jr. of ProBank Austin and Thomas C. Blank of Shumaker, Loop & Kendrick, LLP, special counsel to Comunibanc, were present to review the terms of the letter from Buyer 1 and the other alternatives. Mr. Maroney delivered an analysis of the proposed offer and discussed the pricing and structure relative to other recently completed or announced transactions and anticipated value in a sale transaction. He also reviewed other potential buyer candidates and recent transactions to gauge pricing expectations for the Comunibanc board. Mr. Blank reviewed with the board the letter and consideration of putting in place change of control agreements to keep top management tied to Comunibanc. The board again expressed its desire to remain independent, but agreed that the return to shareholders was of paramount importance, and it was difficult to accomplish this as an independent institution in Henry County Bank’s current markets and with its current operations.

At the request of the board of directors, Mr. Maroney worked with Anthony Grieser, Comunibanc’s Chief Financial Officer, to explore modifications to the projections set forth in the Comunibanc’s previously prepared strategic plan from April 2021, to determine if remaining independent and returning a higher level of profitability to shareholders was feasible.

At a board meeting held on August 2, 2021, the updated information was reviewed by the board of directors. Again, the board expressed its desire to remain independent if consistent with what was in the best interest of its shareholders and other constituents. The board reviewed the difficulties of remaining independent including retention of qualified employees, particularly lenders. They acknowledged the difficulty of attracting qualified talent to Napoleon and the other communities served by Henry County Bank. There also was a review of operational concerns with significant upgrades being required to technology and systems in the near future. Further, the board acknowledged the anticipated retirement of a number of senior officers in the near term. Finally, the board agreed that successfully expanding into new markets could prove difficult.

At the conclusion of the meeting, the board agreed to have further discussions with only Buyer 1 to proceed with the desired independent structure, but with a request for higher pricing. The board agreed to retain ProBank Austin pursuant to its engagement letter dated August 2, 2021. The Board also authorized Mr. Blank to finalize and Mr. Wendt to execute a mutual confidentiality agreement to allow Buyer 1 to perform due diligence on Comunibanc and Henry County Bank and for continued discussions between ProBank Austin, on behalf of the Comunibanc, and Buyer 1 and its investment banking firm representative.

There were ongoing discussions between Buyer 1 and Mr. Maroney that resulted in Buyer 1 submitting a revised offer with a more traditional merger structure. On September 27, 2021 Comunibanc had an additional board meeting with all board members present. Mr. Maroney and Mr. Blank also attended this meeting. With the assistance of Mr. Maroney and Mr. Blank, the Board members reviewed the revised offer, and Mr. Maroney presented a review of the revised offer and compared it to the original offer. He also presented additional information about Buyer 1 and other potential candidates. He was asked to have additional discussions with representatives of Buyer 1 to encourage a revised offer with higher pricing for the transaction.

On October 13, 2021 Buyer 1 submitted a revised expression of interest letter that retained the more standardized merger structure, but had pricing consistent with its initial proposal, a lower amount than the second proposal. The board of directors met on October 18, 2021 to consider the revised offer. Mr. Maroney and Mr. Blank were again present for the meeting. The board reviewed materials from Mr. Maroney on the proposed transaction comparing the now three offers that had been submitted by Buyer 1. There was also discussion about other alternatives with potential other acquirors.

The board members considered the revised offer and the alternative of remaining independent, neither of which seemed a strong option for shareholders of Comunibanc at this point. The board discussed alternatives and determined that Comunibanc needed to consider other potential acquirors. The board authorized Mr. Maroney to contact three additional institutions that it was believed would be interested in acquiring Comunibanc, which

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could accomplish the transaction, and who had liquid stock. The board also authorized Mr. Blank to prepare change in control agreements for Messrs. Grieser and Yarnell and Ms. Mack with restrictive covenants, that it was believed would cause them to remain with Comunibanc, at least through the closing of a transaction.

The board met again on November 12, 2021 to review offers presented by two additional potential suitors, one of which was Civista, and a confirming and final offer from Buyer 1. One of the institutions that had been contacted by Mr. Maroney decided not to submit an offer. Mr. Maroney and Mr. Blank were again present for the meeting. Civista expressed a strong desire for a merger transaction with Comunibanc. Both pricing and cultural philosophies aligned well with what the board thought appropriate. At that meeting, the board approved negotiating exclusively with Civista, but asked Mr. Maroney to push for pricing in excess of $60 per share in order for Civista to be granted exclusivity in negotiation, which Civista had requested. This proposal to negotiate exclusively with Civista and seek an affiliation transaction was unanimously approved at the meeting. The board also reviewed drafts of a form of change in control agreement for three executives as prepared by Mr. Blank and asked that he meet with each of the three executives to discuss a proposed agreement for them. Later that day, Mr. Wendt executed a letter of intent on behalf of Comunibanc, which provided for an increased price of $60.25 per share and provided that Comunibanc would deal exclusively with Civista for a 60-day period. Subsequent to the execution of the letter of intent, Mr. Wendt, upon advice from Mr. Blank, signed an exclusivity agreement with Civista.

From November 12, 2021 until January 7, 2022, Mr. Maroney and Mr. Blank worked with Comunibanc and counsel and financial advisors to Civista to facilitate a due diligence investigation of Comunibanc and Henry County Bank by Civista and a limited reverse due diligence of Civista by Mr. Maroney and representatives of Comunibanc. At the same time, Comunibanc’s executive management, Mr. Blank and Mr. Maroney continued to negotiate the Merger Agreement which Comunibanc’s shareholders are being asked to approve pursuant to this proxy statement/prospectus.

The board of directors of Comunibanc met again on January 7, 2022, to consider the Agreement. All of the Board members were present for the meeting. Mr. Maroney reviewed the process Comunibanc had used to consider the Merger with Civista. This included review of the strategic plan that had been created earlier in 2021, the multiple offers from Buyer 1, consideration of final offers from Buyer 1, Civista and one other interested party, and the negotiations with Civista. Mr. Maroney delivered his oral opinion that the pricing for the transaction set forth in the Merger Agreement was fair, from a financial point of view, to Comunibanc and its shareholders. The oral opinion was followed by a written letter confirming this opinion. After Mr. Maroney delivered his oral fairness opinion, Mr. Blank then reviewed in detail the Merger Agreement with the directors discussing all salient points. He also reviewed the support agreement that all of the directors would be asked to sign in connection with the transaction. Finally, Mr. Blank reviewed the final change in control agreements with each of the executives. Upon a motion duly made and seconded, the directors unanimously approved the Agreement and the Merger and authorized Mr. Wendt and other officers of the Comunibanc to execute and deliver the Agreement and take additional actions necessary to effect the transaction. Mr. Wendt also was authorized by the unanimous approval of the Board to execute each of the change in control agreements on behalf of Comunibanc, which were signed that day.

Mr. Wendt signed the Agreement on the following Monday, January 10, 2022.

Comunibanc’s Reasons for the Merger

Comunibanc’s board of directors unanimously determined that the proposed Merger is in the best interests of Comunibanc and its shareholders. In making its determination, the board of directors considered a number of factors affecting the business, operations, financial condition, earnings, and prospects of Comunibanc. The material factors considered by the board included:

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Comunibanc’s board of directors also considered several potential risks and uncertainties with respect to the Merger and factors unique to certain shareholders of Comunibanc, including, without limitation, the following:

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The foregoing discussion of the material information and factors considered by Comunibanc’s board of directors is not intended to be exhaustive. Comunibanc’s board of directors evaluated the above factors and unanimously determined that the Merger was in the best interests of Comunibanc and its shareholders. In reaching its determination to approve the Merger and recommend that Comunibanc shareholders approve the Merger, the board of directors considered the totality of the information presented to it and did not assign any relative or specific weights to any of the individual factors considered, although individual directors may have given different weights to different factors. The board of directors considered these factors, including the potential risks, uncertainties and disadvantages associated with the Merger, in the aggregate rather than separately and determined the benefits of the Merger to be favorable to and outweigh the potential risks, uncertainties and disadvantages of the Merger. This explanation of the board of directors’ reasoning and certain other information presented in this section are forwarding-looking in nature and, therefore, should be read in the context of the factors discussed under “Cautionary Statement Concerning Forward-Looking Statements.”

Comunibanc’s board of directors determined that the Merger, the Merger Agreement and the transactions contemplated thereby are advisable and in the best interests of Comunibanc and its shareholders. The board of directors also unanimously determined that the Merger Agreement and the transactions contemplated thereby are consistent with, and in furtherance of, Comunibanc’s business strategies. Accordingly, Comunibanc’s board of directors unanimously approved and adopted the Merger Agreement and approved the Merger and unanimously recommends that Comunibanc shareholders vote “FOR” approval of the Merger Agreement and the Merger. The terms of the Merger Agreement were the product of arm’s-length negotiations between Comunibanc and Civista and their respective representatives.

The above discussion of the information and factors considered by Comunibanc’s board of directors is not intended to be exhaustive but includes all material factors considered by the board in arriving at its determination to approve, and to recommend that the Comunibanc shareholders vote to approve the Merger Agreement. The Comunibanc board of directors did not assign any relative or specific weights to the above factors, and individual directors may have given differing weights to each factor.

Recommendation of the Comunibanc Board of Directors

The board of directors of Comunibanc unanimously approved the Merger Agreement. The board of directors of Comunibanc believes that the Merger is in the best interests of Comunibanc and its shareholders, and, as a result, the directors unanimously recommend that Comunibanc shareholders vote “FOR” the adoption and approval of the Merger Agreement and “FOR” the proposal to adjourn the special meeting, if necessary and appropriate, to solicit additional proxies.

Opinion of Comunibanc’s Financial Advisor

On August 2, 2021, Comunibanc retained ProBank Austin to serve as exclusive financial advisor in connection with evaluating and implementing a potential transaction involving the sale or merger of Comunibanc. ProBank Austin is an investment banking and consulting firm specializing in community bank

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mergers and acquisitions. Comunibanc selected ProBank Austin as its financial advisor on the basis of its experience and expertise in representing community banks in similar transactions and its familiarity with Comunibanc.

In its capacity as financial advisor, ProBank Austin provided a fairness opinion (the “ProBank Austin Opinion”) to the board of directors of Comunibanc in connection with the Merger. At the meeting of the Comunibanc board on January 7, 2022, ProBank Austin rendered its oral opinion (which was subsequently confirmed in writing by delivery of ProBank Austin’s written opinion dated January 10, 2022) that, based upon and subject to the various factors, assumptions and limitations set forth in such opinion, ProBank Austin representatives’ experience as investment bankers, ProBank Austin’s work as described in such opinion and other factors ProBank Austin deemed relevant, as of such date, the Merger Consideration set forth in the Merger Agreement was fair, from a financial point of view, to the shareholders of Comunibanc common stock.

The full text of the ProBank Austin Opinion, which sets forth, among other things, the assumptions made, procedures followed, matters considered and limitations on the review undertaken in rendering its opinion, is attached as Annex C to this proxy statement/prospectus and is incorporated herein by reference. The summary of the ProBank Austin Opinion set forth herein is qualified in its entirety by reference to the full text of the opinion. Comunibanc shareholders should read the full text of the opinion carefully and in its entirety. The ProBank Austin Opinion is addressed to the Comunibanc Board, is directed only to the fairness, from a financial point of view, of the Merger Consideration to the holders of Comunibanc common shares, and does not constitute a recommendation to any shareholder as to how such shareholder should vote or act on any matters relating to the Merger.

The ProBank Austin Opinion was reviewed and approved by the fairness opinion committee of ProBank Austin. The description of the opinion set forth below is qualified in its entirety by reference to the opinion. You should consider the following when reading the discussion of ProBank Austin’s opinion in this document:

The preparation of a fairness opinion involves various determinations as to the most appropriate methods of financial analysis and the application of those methods to the particular circumstances. It is, therefore, not readily susceptible to partial analysis or summary description. In performing its analyses, ProBank Austin made numerous assumptions with respect to industry performance, business and economic conditions, and other matters, many of which are beyond the control of Comunibanc and Civista and may not be realized. Any estimates contained in ProBank Austin’s analyses are not necessarily predictive of future results or values, and may be significantly more or less favorable than the estimates. Estimates of values of companies do not purport to be appraisals or necessarily reflect the prices at which the companies or their securities may actually be sold. Unless specifically noted, none of the analyses performed by ProBank Austin was assigned a greater significance by ProBank Austin than any other. The relative importance or weight given to these analyses is not affected by the order of the analyses or the corresponding results. The summaries of financial analyses include information presented in tabular format. The tables should be read together with the text of those summaries.

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With respect to the projections and estimates for Comunibanc and Civista, and the expected transaction costs, purchase accounting adjustments and cost savings, Comunibanc’s and Civista’s management and advisors confirmed to us that they reflected the best currently available estimates and judgments of management of the future financial performance of Comunibanc and Civista, respectively, and ProBank Austin assumed that such performance would be achieved. ProBank Austin expresses no opinion as to such financial projections and estimates or the assumptions on which they are based. ProBank Austin also assumed that there has been no material change in Comunibanc’s or Civista’s assets, financial condition, results of operations, business or prospects since the date of the most recent financial statements made available to us. ProBank Austin assumed, in all respects material to our analysis, that Comunibanc and Civista will remain as going concerns for all periods relevant to the analyses, that all of the representations and warranties contained in the Agreement are true and correct, that each party to the Agreement will perform all of the covenants required to be performed by such party under the Agreement, and that the closing conditions in the Agreement are not waived. Finally, ProBank Austin has relied upon the advice Comunibanc has received from its legal, accounting and tax advisors as to all legal, accounting and tax matters relating to the Merger and the other transactions contemplated by the Agreement.

ProBank Austin has relied, without independent verification, upon the accuracy and completeness of the information it reviewed for the purpose of rendering its opinion. ProBank Austin did not undertake any independent evaluation or appraisal of the assets and liabilities of Comunibanc or Civista, nor was it furnished with any appraisals. ProBank Austin has not reviewed any individual credit files of Comunibanc or Civista, and has assumed that Comunibanc’s and Civista’s allowances are, in the aggregate, adequate to cover inherent credit losses. ProBank Austin’s opinion is based on economic, market and other conditions existing on the date of its opinion. No limitations were imposed by Comunibanc’s board or its management on ProBank Austin with respect to the investigations made or the procedures followed by ProBank Austin in rendering its opinion.

In rendering its opinion, ProBank Austin made the following assumptions:

In connection with its opinion, ProBank Austin reviewed:

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ProBank Austin also discussed with certain members of senior management of Comunibanc the business, financial condition, results of operations and prospects of Comunibanc, including certain operating, regulatory and other financial matters. We held similar discussions with certain members of senior management of Civista regarding the business, financial condition, results of operations and prospects of Civista.

The following is a summary of the material factors considered and analyses performed by ProBank Austin in connection with its opinion dated January 10, 2022. The summary does not purport to be a complete description of the analyses performed by ProBank Austin. Capitalized terms used herein without definition shall have the meanings given to such terms in the Agreement.

Summary of Financial Terms of Agreement. The Agreement provides for each of the 828,504 shares of Comunibanc common stock to be converted into the right to receive: (i) $30.13 in cash (the “Cash Consideration”); and (ii) 1.1888 shares of Civista common stock (the “Stock Consideration”). No fractional shares of Civista will be issued in connection with the Merger, and in lieu thereof, fractional shares will be paid in cash.

Based on 828,504 shares of Comunibanc outstanding common stock, a fixed exchange ratio of 1.1888 and Civista’s closing price of $25.00 on January 5, 2022, the implied value of the Merger Consideration was $49.6 million in the aggregate or $59.85 per share. The implied transaction value of $49.6 million or $59.85 per share represented:

The Agreement provides a termination right to Comunibanc if the Civista’s stock price declines by more than 20 percent as compared to the NASDAQ Bank Index.

Peer Analysis. ProBank Austin compared selected results of Henry County Bank’s operating performance to that of 32 selected commercial banks headquartered in Ohio with total assets between $250 million and $600 million. ProBank Austin considered this group of financial institutions comparable to Henry County Bank on the basis of asset size and geographic location. This peer group consisted of the following banks:

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ProBank Austin noted the following selected financial measures for the peer group as compared to Henry County Bank:

LTM = Last Twelve Months    PTPP = Pre-Tax Pre-Provision = Net Interest Income (FTE) + Noninterest Income – Noninterest Expense    FTE = fully-tax equivalent    Return on Average Assets = ROAA    Return on Average Equity = ROAE    NPAs = Nonperforming assets, defined as loans 90 or more days past due, nonaccrual loans, and Other Real Estate Owned. Restructured loans are not included.

This comparison indicated that Henry County Bank was lower than the 25^th percentile of the peer group in terms of ROAA, ROAE and PTPP earnings to average assets. Henry County Bank’s nonperforming asset levels approximated the median of the peer group. Henry County Bank’s tangible equity to tangible assets ratio was above the median of the peer group.

Comparable Transaction Analysis. ProBank Austin compared the financial performance of certain selling institutions and the prices paid in selected transactions to Comunibanc’s financial performance and the implied transaction multiples being paid by Civista for Comunibanc. Specifically, ProBank Austin reviewed certain information relating to select bank and thrift transactions in Ohio, Michigan, and Indiana announced between January 1, 2020 and December 31, 2021 with seller’s assets less than $3 billion. Twelve (12) transactions were included in this group based on the selected criterion. The following lists the transactions reviewed by ProBank Austin:

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The following table highlights the median results of the guideline M&A transactions:

LTM = Last twelve month

Note: M&A Guideline transactions financial performance based on most recent 12-month data.

The median last twelve-month ROAA ratio of the selling banks in the guideline transactions was 0.75 percent compared to 0.56 percent for Comunibanc. Comunibanc’s ROAE of 5.67 percent was lower than the peer median of 7.32 percent. The median nonperforming assets (“NPA”) to assets ratio measured 0.46 percent for the guideline transaction group which was lower than 0.79 percent for Comunibanc. The indicated price to tangible book ratio being paid by Civista for Comunibanc of 153 percent is lower than the median price to tangible book ratio of 160 percent for the guideline transactions. The implied price-to-earnings multiple for the Comunibanc transaction with Civista of 27.1 times was higher than the median multiple of 21.5 times.

Pro Forma Merger Analysis. ProBank Austin analyzed the potential pro forma effect of the merger to Civista’s performance metrics. Assumptions were made regarding the fair value accounting adjustments, cost savings and other acquisition adjustments based on discussions with management of Comunibanc and Civista and their representatives. For Civista’s stand-alone performance, ProBank Austin relied on input from Civista’s management and their financial advisor for 2022 through 2024. The pro forma merger analysis indicated that the merger is expected to be dilutive to Civista’s tangible book value per share at closing and that such dilution is expected to be recovered within approximately 3.4 years (later revised by Civista to 2.9 years). The merger is expected to be 7.7 percent accretive to Civista’s earnings per share (excluding nonrecurring transaction expenses) for the calendar year 2022 and the accretion is expected to increase to 13.1 percent in the second full year following closing. For all the above analyses, the actual results achieved by Civista following the merger may vary from the projected results and the variance may be material.

ProBank Austin’s Compensation and Other Relationships with Comunibanc and Civista. Comunibanc has agreed to pay ProBank Austin customary fees for its services as exclusive financial advisor in connection with the Merger. Comunibanc paid ProBank Austin $32,500 upon the issuance of the ProBank Austin Opinion. Comunibanc has also agreed to pay ProBank Austin a transaction fee equal to 1.30 percent of the transaction value payable at closing of the Merger.

Comunibanc agreed to reimburse ProBank Austin for its reasonable out-of-pocket expenses, and to indemnify ProBank Austin against certain liabilities, including liabilities under securities laws. ProBank Austin has provided various consulting services to Comunibanc in the past. ProBank Austin does not have any prior, existing or pending engagements with Civista.

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Summary. Based on the preceding summary discussion and analysis, and subject to the qualifications described herein, ProBank Austin determined the Merger Consideration to be fair, from a financial point of view, to the holders of Comunibanc common shares.

The opinion expressed by ProBank Austin was based on market, economic and other relevant considerations as they existed and could be evaluated as of the date of the opinion. Events occurring after the date of issuance of the opinion, including, but not limited to, changes affecting the securities markets, the results of operations or material changes in the financial condition of either Civista or Comunibanc could materially affect the assumptions used in preparing this opinion.

Civista’s Reasons for the Merger

Civista believes that the Merger is in the best interests of Civista and its shareholders. In reaching this determination, the Civista board of directors consulted with its management, as well as its financial, accounting and legal advisors, and considered the projected pro forma impact of the Merger and a number of other factors, including, without limitation, the following:

The board of directors of Civista also considered a variety of risks and other potentially negative factors in deliberations concerning the Merger. In particular, the board of directors of Civista considered:

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other risks described under the sections entitled “RISK FACTORS” beginning on page 21 and “CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS” beginning on page 19.

The above discussion of the information and factors considered by the Civista board of directors is not intended to be exhaustive but includes the material factors considered by the Civista board of directors. In reaching its decision to approve the Merger Agreement, the Merger and the other transactions contemplated by the Merger Agreement, the Civista board of directors did not quantify or assign any relative weights to the factors considered, and individual directors may have given different weights to different factors. The Civista board of directors considered all these factors as a whole, including through its discussions with Civista’s management and financial and legal advisors, in evaluating the Merger Agreement, the Merger, and the other transactions contemplated by the Merger Agreement.

Regulatory Approvals Required

To complete the Merger and Subsidiary Bank Mergers, Civista and Comunibanc need to obtain approvals or consents from, or make filings with, a number of U.S. federal and state bank and other regulatory authorities. Subject to the terms of the Merger Agreement, Civista and Comunibanc have agreed to cooperate with each other and use reasonable best efforts to promptly prepare and file all necessary documentation, to effect all applications, notices, petitions and filings, to obtain as promptly as practicable all permits, consents, approvals and authorizations of all third parties and governmental entities which are necessary or advisable to consummate the transactions contemplated by the Merger Agreement (including the Merger and the Subsidiary Bank Merger), and to comply with the terms and conditions of all such permits, consents, approvals and authorizations of all such third parties and governmental entities. These approvals include, among others, the approval of the Merger and the Subsidiary Bank Merger by the Federal Reserve and the ODFI, respectively. The Merger and the Subsidiary Bank Merger must receive approval from both the ODFI and the Federal Reserve before the Merger may be consummated. On March 4, 2022, Civista submitted the applicable filings to the Federal Reserve for approval and/or nonobjection of the Merger and an application to the Federal Reserve and ODFI for approval of the Subsidiary Bank Merger. The Federal Reserve approved the Subsidiary Bank Merger on April 13, 2022 and approval from ODFI is pending, and is anticipated to follow soon.

The approval of any regulatory applications merely implies the satisfaction of regulatory criteria for approval, which does not include review of the adequacy or fairness of the Merger Consideration to Comunibanc shareholders. Furthermore, regulatory approvals do not constitute or imply any endorsement or recommendation of the Merger or the terms of the Merger Agreement.

Civista and Comunibanc believe that the Merger does not raise significant regulatory concerns and that they will be able to obtain all requisite regulatory approvals. However, there can be no assurance that all of the regulatory approvals described herein will be obtained and, if obtained, there can be no assurances regarding the timing of the approvals, the companies’ ability to obtain the approvals on satisfactory terms or the absence of litigation challenging such approvals. In addition, there can be no assurance that such approvals will not impose conditions or requirements that, individually or in the aggregate, would or could reasonably be expected to have an adverse effect on the financial condition, results of operations, assets or business of the combined company

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following completion of the Merger. There can likewise be no assurances that U.S. federal or state regulatory or competition authorities will not attempt to challenge the Merger or, if such a challenge is made, what the result of such challenge will be.

Interests of Comunibanc Directors and Officers in the Merger

As described below, some of Comunibanc’s directors and executive officers have interests in the Merger that may be different from, or in addition to, the interests of Comunibanc shareholders generally. The Comunibanc board of directors was aware of these interests and considered them in approving the Merger Agreement.

Change-in-Control Agreements. Comunibanc and Henry County Bank are parties to certain change in control agreements with certain executive officers.

Anthony Grieser has a change in control agreement with Comunibanc and Henry County Bank. Under that agreement, in the event of the Merger, Mr. Grieser will be entitled to receive a payment equal to 2.5 times the sum of his (i) base salary, as in effect immediately prior to the effective date of the Merger, and (ii) the average annual bonus paid to, or earned by, Mr. Grieser during the two (2) calendar years immediately preceding the effective date of the Merger. The estimated benefit payable to Mr. Grieser under the terms of his change in control agreement as a result of the Merger is $500,753.

Sharon Mack has a change in control agreement with Comunibanc and Henry County Bank. Under that agreement, in the event of the Merger, Ms. Mack will be entitled to receive a payment equal to 1.0 times the sum of her (i) base salary, as in effect immediately prior to the effective date of the Merger, and (ii) the average annual bonus paid to, or earned by, Ms. Mack during the two (2) calendar years immediately preceding the effective date of the Merger. Ms. Mack will be entitled to a second payment equal to 0.5 times her base salary and the average annual bonus paid to, or earned by, Ms. Mack during the two (2) calendar years immediately preceding the effective date of the Merger, provided however that Ms. Mack remains employed by Comunibanc, Henry County Bank or any successor entity of either as of October 31, 2022, or earlier if Ms. Mack is terminated without cause by Comunibanc, Henry County Bank, or any successor entity prior to October 31, 2022, in which case payment will be made within seven (7) days of termination. The estimated benefit payable to Ms. Mack under the terms of her change in control agreement as a result of the Merger is $275,430, of which $183,620 which will be paid at the time of the Merger and $91,810 will be paid subject to certain conditions and on a delayed basis as provided for above.

James K. Yarnell has a change in control agreement with Comunibanc and Henry County Bank. Under that agreement, in the event of the Merger, Mr. Yarnell will be entitled to receive a payment equal to 1.5 times the sum of his (i) base salary, as in effect immediately prior to the effective date of the Merger, and (ii) the average annual bonus paid to, or earned by, Mr. Yarnell during the two (2) calendar years immediately preceding the effective date of the Merger. The estimated benefit payable to Mr. Yarnell under the terms of his change in control agreement as a result of the Merger is $258,573.

Severance Payments

Under the terms of the Merger Agreement Civista shall pay to each employee of Comunibanc or its Subsidiaries who (i) is not subject to an existing contract providing for severance and/or a change in control payment, (ii) is an employee of Comunibanc or any of its Subsidiaries immediately before the Effective Time, (iii) is not offered continued employment by Civista or any of its Subsidiaries after the Effective Time or is terminated by Civista without cause within three (3) months after the Effective Time, and (iv) who sign and deliver Civista’s standard form of termination and release agreement, a severance amount equal to two weeks of pay, at their base rate of pay in effect at the time of termination, multiplied by the number of whole years of service of such employee with Comunibanc or any of its Subsidiaries, less applicable local, state and federal tax

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withholding; provided, however, that the minimum severance payment shall equal four weeks of base pay, and the maximum severance payment shall not exceed 26 weeks of base pay. Such severance pay shall be paid in a lump sum within 14 days following the employee’s termination, provided that such employee has not been terminated for cause. In addition, Civista will offer outplacement assistance to any such terminated employee for the same period of time during which such employee is entitled to severance hereunder. For any employee of Comunibanc or its Subsidiaries participating in Comunibanc’s, or any of its Subsidiaries’, group health program at the Effective Time who is entitled to a severance payment, the employee will be able to purchase health insurance coverage at the full premium rate for the entire COBRA period; Civista will pay the cost of COBRA coverage for such employees for a period equal to the number of weeks such employee is entitled to severance.

Mr. Anthony E. Grieser, the Chief Financial Officer of Henry County Bank, has entered into an independent consulting agreement with Civista to be effective as of the closing of the Merger. Mr. Grieser is agreeing to assist Civista, on an as needed basis, until completion of core banking processor data conversion, in October of 2022, providing advice and support in the management of the existing accounting and financial reporting systems of Henry County Bank, and the preparation and processing of accounting and financial reports relating to the Henry County Bank’s business. Civista will pay Mr. Grieser $100 per hour of actual work completed pursuant to the terms of the agreement.

Indemnification and Directors’ and Officers’ Liability Insurance

Subject to compliance with applicable state and federal laws, Civista will indemnify each person who served as a director or officer of Comunibanc on or after the date of the Merger Agreement and before the Effective Time of the Merger to the fullest extent provided by Comunibanc’s governing documents and applicable law, from and against expenses, including attorneys’ fees, judgments, fines and amounts paid in settlement in connection with any threatened, pending or completed action, suit or proceeding by reason of the fact that the person was an officer or director of Comunibanc or Henry County Bank. In addition, the Merger Agreement provides that, prior to the Merger, Comunibanc will purchase a directors’ and officers’ and company liability insurance policy to be effective for up to six years following the effective date of the Merger, on terms no less advantageous than those contained in Comunibanc’s existing policy, provided, however, that the premium on the policy shall not exceed 150% of Comunibanc’s current premium levels.

Director Appointments

Promptly following the Effective Time, Civista shall cause one (1) person who is currently a member of the Comunibanc Board to be vetted and appointed to the Civista Bank board of directors for a term commencing as soon as practicable after the Effective Time, in accordance with the Civista Bank regulations, corporate governance guidelines, and applicable law. The person selected to be appointed to the Civista Bank board will be mutually agreed to in writing by Civista and Comunibanc, acting in good faith.

Termination and payout of certain fully vested compensation agreements.

Director Deferred Fee Agreements and Director Supplemental Retirement Program. Henry County Bank maintains a voluntary director deferred fee plan (“Deferred Fee Plan”) and a Director Supplemental Retirement Program (the “Director Deferred Plan”). Directors Chamberlin, Fisher, Freppel, Stober, and Wendt participate in the Deferred Fee Plan and directors Anthony E. Grieser, Jacob A. Freppel, and William L. Wendt participate in the Director SERP Plan. All participants are fully vested in their benefits and the obligations of Henry County Bank are fully accrued for under both plans. Under the terms of the Merger Agreement, Henry County Bank will take action to terminate the Director Fee Plan and the Director SERP plan at or immediately prior to the Effective Time and distribute the vested and accured benefits to the participating directors.

Salary Reduction Deferred Compensation Agreements. Henry County Bank maintains a voluntary salary reduction deferred compensation plan (the “Executive Deferred Compensation Plan”). Henry County Bank

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officers Anthony E. Grieser, Sharon S. Mack, William L. Wendt, David L. Wills, and J. Kevin Yarnell each have elected to participate in the plan. Participants are at all times fully vested in their volutary deferral amounts and the obligations of Henry County Bank are fully accrued for under the plan. Under the terms of the Merger Agreement, Henry County Bank will take action to terminate the Executive Deferred Compensation Plan at or immediately prior to the Effective Time and distribute the vested and accrued benefits to the participating executives.

Split Dollar Agreements

Henry County Bank maintains split dollar plans for the benefit of its directors and officers. Under the terms of the plans participants have the right during and after employment to designate beneficiares to receive death benefits from life insuarnce policies owned by Henry County Bank and maintained on the life of the participant. Except for directors Fisher and Freppel, all participants under the director and officer split dollar plan are fully vested in their split dollar benefits based upon their current service and the actuarial net present value of the obligations of Henry County Bank have been fully accrued. Directors Fisher and Freppel have not fulfilled the employment service requirement to be vested in their benefit, but their benefit will become fully vested in connection with the Merger under the terms of the change in control provisions of their split dollar agreements. As of December 31, 2021, the most recent date for which information is available, the accuarial net present value of the unaccrued split dollar benefit that will accelerate and vest upon the Merger was $7,751 and $25,571 for Mr. Fisher and Mr. Freppel, respectively. Civista has agreed in the Merger Agreement to assume the obligations of Henry County Bank under the split dollar agreement. If requested by Civista, Comunibanc and Henry County Bank have agreed to use their reasonable best efforts to terminate each participant agreement under the Split Dollar Plans. Any payment made to a participant in connection with the termination of their respective split dollar agreement under the Split Dollar Plans must be approved by Civista prior to payment.

MERGER-RELATED COMPENSATION TO NAMED EXECUTIVE OFFICERS

The discussion and table below reflect the estimated amount of compensation and benefits that each of the named executive officers of Comunibanc and Henry County Bank are entitled to receive where the compensation or benefits are based on or otherwise relate to the Merger.

The amounts in the table below assume the named executive officer remains employed and is not terminated with cause as of the Effective Time. Amounts do not include compensation benefits available to all of Comunibanc’s general employees on a non-discriminatory basis. All of the employment arrangements described above comply with or are excepted from Section 409A of the Internal Revenue Code.

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Material U.S. Federal Income Tax Consequences of the Merger

This section describes the intended, material U.S. federal income tax consequences of the Merger to Civista, Comunibanc, and U.S. holders of Comunibanc common shares who exchange their shares for a combination of Civista common shares and cash pursuant to the Merger. Civista and Comunibanc intend for the Merger to be treated as a “reorganization” within the meaning of Section 368(a)(1)(A) of the Internal Revenue Code, and Civista and Comunibanc intend that each will be a “party to the reorganization” within the meaning of Section 368(b) of the Internal Revenue Code. Civista has received an opinion of Dinsmore & Shohl LLP, and Comunibanc has received an opinion of Shumaker, Loop & Kendrick, LLP, dated as of the effective date of the Merger, substantially to the effect that, on the basis of facts, representations and assumptions set forth in that opinion (including factual representations contained in certificates of officers of Civista and Comunibanc), the Merger constitutes a reorganization under Section 368(a) of the Internal Revenue Code.

The following discussion assumes that the U.S. Internal Revenue Service (“IRS”) and the courts agree that the Merger is a reorganization within the meaning of Section 368(a)(1)(A) of the Internal Revenue Code, and that Civista and Comunibanc are each a “party to the reorganization” within the meaning of Section 368(b) of the Internal Revenue Code. However, Civista and Comunibanc have not requested and do not intend to request any ruling from the IRS as to the U.S. federal income tax consequences of the Merger, and the tax opinions to be delivered in connection with the Merger are not binding on the IRS or any court or other administrative body. Consequently, there is no assurance of the accuracy of the anticipated U.S. federal income tax consequences to Civista, Comunibanc, and the shareholders of Comunibanc described in this proxy statement/prospectus. In addition, if any of the facts, representations or assumptions upon which the opinions are based are inconsistent with the actual facts, the U.S. federal income tax consequences of the Merger could be adversely affected. The actual tax consequences to you of the Merger may be complex and will depend upon your specific situation and upon factors that are not within the control of Civista or Comunibanc. You should consult with your own tax advisor as to the tax consequences of the Merger in light of your particular circumstances, including the applicability and effect of the alternative minimum tax and any state, local, foreign, and other tax laws, your basis in any Civista common shares received in the Merger, your holding period with respect to any Civista common shares received in the Merger, your tax return reporting requirements, or the applicability and effect of any proposed changes in any tax laws.

The following discussion is based on the Internal Revenue Code, existing and proposed Treasury Department regulations promulgated thereunder and published judicial and administrative rulings and decisions, all as currently in effect as of the date hereof, and all of which are subject to change, possibly with retroactive effect. Any such change could affect the continuing validity of this discussion. This summary does not address any tax consequences of the Merger under state, local or foreign laws, or any federal laws other than those pertaining to income tax.

For purposes of this discussion, a “U.S. holder” is a beneficial owner of Comunibanc common shares who, for U.S. federal income tax purposes, is:

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If a partnership (including for this purpose any entity or arrangement treated as a partnership for U.S. federal income tax purposes) holds Comunibanc common shares, the tax treatment of a partner generally will depend on the status of the partners and the activities of the partnership. If you are a partnership, or a partner in such partnership, holding Comunibanc common shares, you should consult your tax advisors.

This discussion is applicable only to those U.S. resident Comunibanc shareholders that hold their Comunibanc common shares as a capital asset within the meaning of Section 1221 of the Internal Revenue Code (generally, property held for investment), and does not address all of the U.S. federal income tax consequences that may be relevant to particular Comunibanc shareholders in light of their individual circumstances or to Comunibanc shareholders that are subject to special rules, such as:

In addition, the discussion does not address any alternative minimum tax, U.S. federal estate or gift tax or any state, local or foreign tax consequences of the Merger, nor does it address any tax consequences arising under the unearned income Medicare contribution tax pursuant to the Health Care and Education Reconciliation Act of 2010 or any consequences under the Foreign Account Tax Compliance Act of 2010 (including the Treasury Department regulations issued thereunder and intergovernmental agreements entered into pursuant thereto or in connection therewith). Determining the actual tax consequences of the Merger may be complex.

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They will depend on specific situations and on factors that are not within the control of Comunibanc or Civista All holders of Comunibanc common shares should consult their tax advisors as to the specific tax consequences of the Merger to them, including the applicability and effect of the alternative minimum tax and any state, local, foreign, and other tax laws, your basis in any Civista common shares received in the Merger, your holding period with respect to any Civista common shares received in the Merger, your tax return reporting requirements, or the applicability and effect of any proposed changes in any tax laws.

The following discussion summarizes the matters addressed in the tax opinion of Dinsmore & Shohl LLP and Shumaker, Loop & Kendrick LLP filed as an exhibit to the registration statement of which this proxy statement/prospectus is a part.

Reorganization Treatment

The Merger is intended to be a reorganization within the meaning of Section 368(a)(1)(A) of the Internal Revenue Code, and Civista and Comunibanc are each intended to be a “party to the reorganization” within the meaning of Section 368(b) of the Internal Revenue Code. If the intended reorganization treatment is respected by the Internal Revenue Service and the courts, then the material federal income tax consequences described below are anticipated.

Federal Income Tax Consequences to Civista and Comunibanc

No Gain or Loss. No gain or loss will be recognized by Civista or Comunibanc as a result of the Merger.

Tax Basis. The aggregate tax basis of the assets of Comunibanc in the hands of Civista will be the same as the aggregate tax basis of such assets in the hands of Comunibanc immediately prior to the Merger.

Holding Period. The holding period of the assets of Comunibanc to be received by Civista will include the period during which such assets were held by Comunibanc.

Federal Income Tax Consequences to U.S. Holders of Comunibanc Common Shares

The U.S. federal income tax consequences of the Merger to a U.S. holder will depend on whether such U.S. holder receives cash or a combination of cash and Civista common shares in exchange for such U.S. holder’s Comunibanc common shares. Although the Exchange Ratio, Cash Consideration, and Stock Consideration provisions of the Merger Agreement are generally fixed, cash payments in lieu of fractional Civista common shares or in connection with dissenters’ rights could alter the mix of consideration a shareholder will receive.

Exchange of Comunibanc Common Shares for a combination of Civista Common Shares and Cash

A U.S. holder of Comunibanc common shares will recognize gain (but not loss) with respect to the Civista common shares and cash such U.S. holder receives pursuant to the Merger in an amount equal to the lesser of (i) the amount by which the sum of the fair market value of the Civista common shares and the amount of cash received by such U.S. holder, exceeds such U.S. holder’s basis in its Comunibanc common shares surrendered in the Merger, and (ii) the amount of cash received by such U.S. holder (other than any cash received in lieu of a fractional Civista common share, as discussed below under “—Cash In Lieu of Fractional Shares”). For purposes of this calculation, the fair market value of Civista common shares is based on the trading price of Civista common shares on the date of the Merger, rather than price negotiated between Civista and Comunibanc in the Merger Agreement used to calculate the number of shares of Civista common stock to be issued to the shareholder. In the case of any U.S. holder who acquired different blocks of Comunibanc common shares at different times and at different prices, any realized gain or loss will be determined separately for each identifiable block of Comunibanc common shares exchanged in the Merger. A loss realized on the exchange of one block cannot be used to offset a gain realized on the exchange of another block, but a U.S. holder will generally be able

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to reduce its capital gains by capital losses in determining its income tax liability. Prior to voting on the Merger, any U.S. holder potentially in that circumstance should consult its tax advisor with regard to identifying the basis or holding periods of the particular Civista common shares received in the Merger. Subject to possible dividend treatment (as discussed in more detail under “—Possible Dividend Treatment,” below), gain that U.S. holders of Comunibanc common shares recognize in connection with the Merger generally will constitute capital gain if they held such stock as a capital asset at the time of the Merger and will constitute long-term capital gain if such holders have held their Comunibanc common shares for more than one year at the effective time of the Merger. Long-term capital gain of certain non-corporate U.S. holders of Comunibanc common shares, including individuals, is generally taxed at preferential rates. The deductibility of capital losses is subject to limitations.

The tax basis of the Civista common shares received by a U.S. holder of Comunibanc common shares described above (including a fractional Civista common share, if any, deemed issued and redeemed by Civista) will be the same as the tax basis of the Comunibanc common shares surrendered in exchange for the Civista common shares and cash, reduced by the amount of cash received by such a U.S. holder in the Merger (other than any cash received in lieu of a fractional Civista common share), and increased by any gain recognized by such a U.S. holder in the Merger (including any portion of the gain that is treated as a dividend (as described below), but excluding any gain or loss resulting from the deemed issuance and redemption of a fractional Civista common share). The holding period for Civista common shares received by such a U.S. holder (including a fractional Civista common share, if any, deemed to be issued and redeemed by Civista) will include such U.S. holder’s holding period for Comunibanc common shares surrendered in exchange for the Civista common shares.

Cash in Lieu of Fractional Shares

A U.S. holder of Comunibanc common shares that receives cash in lieu of a fractional Civista common share generally will be treated as having received such fractional share and then having received such cash in redemption of such fractional share. Gain or loss generally will be recognized based on the difference between the amount of cash received in lieu of the fractional share and the portion of the U.S. holder’s aggregate adjusted basis in the Comunibanc common shares surrendered which is allocable to the fractional share. Subject to possible dividend treatment (as discussed in more detail under “Possible Dividend Treatment”, below), such gain or loss generally will be long-term capital gain or loss if the U.S. holder held such stock as a capital asset at the time of the Merger and the U.S. holder’s holding period for its Comunibanc common shares exceeds one year at the effective time of the Merger. The Internal Revenue Code contains limitations on the extent to which a taxpayer may deduct capital losses from ordinary income.

Tax Consequences to Comunibanc Shareholders who Receive Only Cash

A U.S. holder of Comunibanc common shares who properly exercises its dissenters’ rights and receives solely cash in exchange for all of its Comunibanc common shares (and is not treated as constructively owning Civista common shares after the Merger under the circumstances referred to below under “Possible Dividend Treatment”) will recognize a gain or loss for federal income tax purposes equal to the difference between the cash received and such U.S. holder’s tax basis in Comunibanc’s common shares surrendered in exchange for the cash. Subject to possible dividend treatment (as discussed in more detail under “Possible Dividend Treatment”, below), such gain or loss will be a capital gain or loss, provided that such shares were held as capital assets of the U.S. holder at the effective time of the Merger. Such gain or loss will be long-term capital gain or loss if the U.S. holder’s holding period is more than one year. The Internal Revenue Code contains limitations on the extent to which a taxpayer may deduct capital losses from ordinary income.

Possible Dividend Treatment

In some cases, if a U.S. holder of Comunibanc common shares actually or constructively owns Civista common shares other than the Civista common shares received pursuant to the Merger, the gain recognized by such holder could be treated as having the effect of the distribution of a dividend under tests set forth in the

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Internal Revenue Code, in which case such gain would be treated as dividend income. This could happen, for example, because of ownership of additional Civista common shares by such holder, ownership of Civista common shares by a person related to such holder, or a share repurchase by Civista from other holders of Civista common shares. Because the possibility of dividend treatment depends primarily upon each holder’s particular circumstances, including the application of certain constructive ownership rules, U.S. holders of Comunibanc’s common shares should consult their tax advisors regarding the application of the foregoing rules to their particular circumstances.

Backup Withholding and Reporting Requirements

Under certain circumstances, cash payments made to a U.S. holder of Comunibanc common shares pursuant to the Merger may be subject to backup withholding at a rate of 28% of the cash payable to the holder, unless the holder furnishes its taxpayer identification number in the manner prescribed in applicable Treasury Department regulations, and otherwise complies with all applicable requirements of the backup withholding rules. Any amounts withheld from payments to a holder under the backup withholding rules are not an additional tax and will be allowed as a refund or credit against the holder’s U.S. federal income tax liability, provided that the required information is timely furnished to the IRS.

A U.S. holder of Comunibanc common shares owning at least 5% (by vote or value) of the outstanding shares of Comunibanc common shares or having a basis of $1,000,000 or more in its Comunibanc common shares, immediately before the Merger, is required to file a statement with such holder’s U.S. federal income tax return setting forth such holder’s tax basis in and the fair market value of shares of the Comunibanc common shares exchanged by such holder pursuant to the Merger. In addition, all U.S. holders of Comunibanc common shares will be required to retain records pertaining to the Merger.

The preceding discussion of material U.S. federal income tax consequences of the Merger is included in this proxy statement/prospectus for general information only, and is intended only as a summary of material U.S. federal income tax consequences of the Merger. It is not a complete analysis or discussion of all potential tax effects that may be important to you and is not tax advice.

We recommend that each Communibanc shareholder consult with his, her or its own tax advisor regarding the specific tax consequences to the shareholder of the Merger, including the application and effect of state, local and foreign income and other tax laws.

Accounting Treatment

The Merger will be accounted for under the acquisition method of accounting in accordance with generally accepted accounting principles in the United States. Under the acquisition method of accounting, the assets and liabilities of Comunibanc will be recorded and assumed at estimated fair values at the time the Merger is consummated. The excess of the estimated fair value of Civista common shares issued and the cash proceeds paid over the net fair values of the assets acquired, including identifiable intangible assets, and liabilities assumed will be recorded as goodwill and will not be deductive for income tax purposes. Goodwill will be subject to an annual test for impairment and the amount impaired, if any, will be charged as an expense at the time of impairment.

Resale of Civista’s Common Shares

Civista has registered its common shares to be issued in the Merger with the SEC under the Securities Act of 1933, as amended (the “Securities Act”). No restrictions on the sale or other transfer of Civista’s common shares issued in the Merger will be imposed solely as a result of the Merger, except for restrictions on the transfer of Civista’s common shares issued to any Comunibanc shareholder who may become an “affiliate” of Civista for purposes of Rule 144 under the Securities Act. The term “affiliate” is defined in Rule 144 under the Securities Act and generally includes executive officers, directors and shareholders beneficially owning 10% or more of the outstanding Civista common shares.

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THE MERGER AGREEMENT

The following is a description of the material terms of the Merger Agreement. A complete copy of the Merger Agreement is attached as Annex A to this proxy statement/prospectus and is incorporated into this proxy statement/prospectus by reference. We encourage you to read the Merger Agreement carefully, as it is the legal document that governs the Merger.

The Merger Agreement contains representations and warranties of Comunibanc and Civista. The assertions embodied in those representations and warranties are qualified by information contained in confidential disclosure schedules that the parties delivered in connection with the execution of the Merger Agreement. In addition, certain representations and warranties were made as of a specific date, may be subject to a contractual standard of materiality different from the standard of materiality generally applicable to statements made by a corporation to shareholders or may have been used for purposes of allocating risk between the respective parties rather than establishing matters as facts. Accordingly, you should not rely on the representations and warranties as characterizations of the actual state of facts, or for any other purpose, at the time they were made or otherwise.

The Merger and Subsidiary Bank Mergers

Pursuant to the terms and subject to the conditions of the Merger Agreement, upon filing the applicable certificate of merger, Comunibanc will merge with and into Civista, with Civista surviving the Merger and continuing as an Ohio corporation and a registered financial holding company and the separate corporate existence of Comunibanc shall cease. Immediately after the Merger or at such later time specified by Civista, Civista will cause Henry County Bank to be merged with and into Civista Bank, with Civista Bank surviving the Merger and continuing as an Ohio-chartered commercial bank.

Effective Time

Civista and Comunibanc will cause the effective date of the Merger to occur as soon as practicable after the last of the conditions set forth in the Merger Agreement have been satisfied or waived. Unless Civista and Comunibanc otherwise agree in writing, the effective date of the Merger will not be later than November 30, 2022. The Merger will become effective upon the later to occur of (a) the filing of a certificate of merger with the Ohio Secretary of State, or (b) at a later time that Civista and Comunibanc agree to in writing and specify in the certificate of merger.

Civista and Comunibanc currently anticipate closing the Merger and filing the certificate of merger with the Ohio Secretary of State in the second quarter of 2022.

Merger Consideration

Under the terms of the Merger Agreement, if the Merger is completed, shareholders of Comunibanc will be entitled to receive for each Comunibanc common share: (i) $30.13 in cash and (ii) 1.1888 Civista common shares (the “Merger Consideration”).

The value of the cash consideration to be received by each Comunibanc shareholder with respect to each common share is fixed at $30.13. The implied value of stock consideration will fluctuate as the market price of Civista common shares fluctuates before the completion of the Merger. The value of the stock consideration that a Comunibanc shareholder actually receives will be based on the closing price on the Nasdaq Capital Market^® of Civista common shares upon completion of the Merger.

Civista will not issue any fractional common shares in connection with the Merger. Instead, each holder of Comunibanc common shares who would otherwise be entitled to receive a fraction of a Civista common share

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(after taking into account all Comunibanc common shares owned by such holder at the effective time of the Merger) will receive cash, without interest, in an amount (rounded to the nearest cent) equal to the Civista fractional common share to which such holder would otherwise be entitled, multiplied by (i) the average of the closing-sale prices of Civista common shares on the Nasdaq Capital Market^® as reported by The Wall Street Journal for the five (5) consecutive full trading days ending on the trading day preceding the closing date by (ii) the fraction of a share (rounded to the nearest one-thousandth when expressed in decimal form) of Civista common shares which such holder would otherwise be entitled to receive.

The Merger Agreement also requires that the merger consideration, specifically the Exchange Ratio, be adjusted if the number of Comunibanc common shares or the Civista common shares outstanding between the date of the Merger Agreement and the effective time shall have been increased, decreased, changed into or exchanged for a different number or kind of shares or securities, in any such case as a result of a reorganization, recapitalization, reclassification, stock dividend, stock split, reverse stock split, or other similar change in capitalization, or there shall be any extraordinary dividend or extraordinary distribution to give holders of the Comunibanc common shares the same economic effect contemplated by the Merger Agreement prior to any such event.

Additionally, in order to satisfy the “continuity of interest” requirements under applicable federal income tax principles relating to reorganizations under Section 368(a) of the Internal Revenue Code, Civista may increase the stock Consideration per share (and cause a corresponding decrease in the cash Consideration per share equal to the economic value of any such increase) to the minimum extent necessary to enable the Merger to satisfy the “continuity of interest” requirements under applicable federal income tax principles relating to reorganizations under Section 368(a) of the Code.

At the effective time of the Merger, Comunibanc common shares will no longer be outstanding and will automatically be cancelled and cease to exist, and holders of Comunibanc common shares will cease to be, and will have no rights as, shareholders of Comunibanc, other than to receive the merger consideration pursuant to the terms and conditions of the Merger Agreement (and dissenters’ rights under Section 1701.85 of the OGCL in the case of Comunibanc common shares as to which the holder has properly exercised dissenters’ rights).

Under certain circumstances involving a fall in the market price of Civista common shares, Civista may, at its election, increase the Merger consideration by adjusting the Exchange Ratio in order to avoid termination of the Merger Agreement.

See the section of this discussion titled “—Termination of the Merger Agreement” for more information.

Exchange and Payment Procedure; Surrender of Certificates

Civista will engage American Stock Transfer & Trust Company, LLC (the “Exchange Agent”) to act as its exchange agent to handle the exchange of Comunibanc common shares for the merger consideration. As soon as practicable, but not more than five business days after the effective time, the Exchange Agent will send to each Comunibanc shareholder a letter of transmittal for use in the exchange with instructions explaining how to surrender Comunibanc common share certificates (or book entry shares) to the Exchange Agent. Comunibanc shareholders that surrender their certificates to the Exchange Agent, together with a properly completed letter of transmittal, will receive the merger consideration, including the stock consideration and cash consideration, plus any cash payable in lieu of any fractional shares of Civista, and any dividends or distributions such holder has the right to receive pursuant to the Merger Agreement. Comunibanc shareholders that do not exchange their Comunibanc common shares will not be entitled to receive the Merger Consideration or any dividends or other distributions by Civista until their certificates are surrendered. Only after surrender of the certificates representing Comunibanc shares, will any unpaid dividends or distributions with respect to Civista common shares represented by the certificates be paid, without interest. No interest will be paid or accrue on any cash

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Merger consideration or cash in lieu of fractional shares or dividends or distributions payable to the Comunibanc shareholders.

After the effective time of the Merger, the stock transfer books of Comunibanc will be closed and there will be no further registration of transfers of Comunibanc common shares on the records of Comunibanc. Any certificates or book entry shares presented to Civista after the effective time will be cancelled and exchanged in accordance with the Merger Agreement.

Any portion of the exchange fund that remains unclaimed by the shareholders of Comunibanc for six months following the effective time of the Merger will be paid to the surviving corporation. From and after such time, any former holders of Comunibanc common shares who have not properly surrendered their shares may thereafter seek only from the surviving corporation the Merger consideration payable in respect of such Comunibanc common shares, any cash payable in lieu of any fractional shares of Civista and any dividends or distributions such holder has the right to receive pursuant to the Merger Agreement.

If any certificate representing Comunibanc common shares is lost, stolen or destroyed, upon the making of an affidavit of such fact by the person claiming the certificate to be lost, stolen or destroyed and, if required by Civista or the Exchange Agent, the posting by such person of a bond in such amount as Civista or the Exchange Agent may determine is reasonably necessary as indemnity against any claim that may be made against it with respect to such certificate, the Exchange Agent or Civista, as applicable, will issue in exchange for the lost, stolen or destroyed certificate the applicable Merger consideration, cash in lieu of fractional shares and any dividends or other distributions that have been payable or become payable in respect of the Comunibanc common shares represented by that certificate pursuant to the Merger Agreement.

Civista will be entitled to deduct and withhold, or cause the Exchange Agent to deduct and withhold, from any Merger consideration or other amounts payable pursuant to the Merger Agreement to any holder of Comunibanc common shares such amounts as Civista or the Exchange Agent is required to deduct or withhold under applicable tax laws, and any such withheld amounts that are paid to the appropriate taxing authorities will be treated for purposes of the Merger Agreement as having been paid to the holder of Comunibanc common shares from whom such amounts were deducted or withheld.

Comunibanc Shares in the ESOP

At the Effective Time, any remaining shares of Comunibanc common shares held in the Comunibanc ESOP shall be converted into the right to receive, without interest, the Merger Consideration. Within sixty (60) days following the Effective Time, Civista and the ESOP Trustee shall arrange to request from the IRS a determination that the termination of the Comunibanc ESOP is in compliance with Sections 401(a) and 409 of the Code. Civista and the ESOP trustee shall arrange to make partial distributions of up to 75% of the account balances credited to the ESOP participants as of the effective date (taking into account that portion of the Merger Consideration received by the ESOP on the effective date) as soon as administratively practicable after the effective date, with the remaining portion to be distributed as soon as administratively practicable after receipt by Civista of the ESOP determination letter.

Indemnification and Directors’ and Officers’ and Company Liability Insurance

For a period of six (6) years after the effective time of the Merger and subject to compliance with applicable state and federal laws, Civista will indemnify each person who served as a director or officer of Comunibanc on or after the date of the Agreement and before the effective time of the Merger to the fullest extent provided by Comunibanc’s governing documents, from and against expenses, including attorneys’ fees, judgments, fines and amounts paid in settlement in connection with any threatened, pending or completed action, suit or proceeding by reason of the fact that the person was an officer or director of Comunibanc. In addition, the Merger Agreement provides that, prior to the Merger, Comunibanc will procure, at the expense of Civista, a policy of directors’ and

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officers’ and company liability insurance to be effective for a period of up to six years following the Merger, on terms no less advantageous than those contained in Comunibanc’s existing policy. However, the combined company is not obligated to expend an amount in excess of 150% of the current annual premium paid as of the date of the Merger Agreement by Comunibanc for such insurance (the “premium cap”).

Employee Matters

Participation by Comunibanc Employees in Civista’s Employee Benefit Program(s): The Merger Agreement provides that employees of Comunibanc or the Subsidiary Bank who become employees of Civista as a result of the Merger will, as determined by Civista, participate in the employee benefit plans sponsored by Civista for Civista’s employees immediately after the Effective Date. Employees of Comunibanc or the Subsidiary Bank will receive credit for their years of service with Comunibanc or the Subsidiary Bank, as applicable, for participation and vesting purposes under the applicable Civista employee benefit plans, including credit for years of service and for seniority under Civista’s vacation and sick pay plans and programs, but subject to the eligibility and other terms of such plans. In addition, Civista will waive all restrictions and limitations on pre-existing conditions to the extent the group health plan and insurance policy of Civista or Civista Bank permit (or may be amended to permit), and give effect, in determining any deductible, co-insurance and maximum out-of-pocket limitations, to amounts paid by such continuing employees (and their covered dependents) under the group health plan maintained by Comunibanc or the Subsidiary Bank during the portion of the 2022 plan year prior to the Effective Time.

Severance: Subject to any applicable regulatory restrictions, Civista shall pay to each employee of Comunibanc or its subsidiaries who (i) is not subject to an existing contract providing for severance and/or a change in control payment, (ii) is an employee of Comunibanc or any of its subsidiaries immediately before the Effective Time, (iii) is not offered continued employment by Civista or any of its subsidiaries after the Effective Time or is terminated by Civista without cause within three (3) months after the Effective Time, and (iv) who sign and deliver Civista’s standard form of termination and release agreement, a severance amount equal to two weeks of pay, at their base rate of pay in effect at the time of termination, multiplied by the number of whole years of service of such employee with Comunibanc or any of its Subsidiaries, less applicable local, state and federal tax withholding; provided, however, that the minimum severance payment shall equal four weeks of base pay, and the maximum severance payment shall not exceed 26 weeks of base pay. Such severance pay shall be paid in a lump sum within 14 days following the employee’s termination, provided that such employee has not been terminated for cause. In addition, Civista will offer outplacement assistance to any such terminated employee for the same period of time during which such employee is entitled to severance. For any employee of Comunibanc or its Subsidiaries participating in Comunibanc’s, or any of its subsidiaries’, group health program at the Effective Time who is entitled to a severance payment, the employee will be able to purchase health insurance coverage at the full premium rate for the entire COBRA period. Civista will pay the cost of COBRA coverage for such employees for a period equal to the number of weeks such employee is entitled to severance.

Termination of The Henry County Bank Profit Sharing and 401(k) Plan (the “Communibanc 401(k) Plan”): Comunibanc is required to terminate the Comunibanc 401(k) Plan effective immediately prior to the effective time of the Merger. In addition, as soon as feasible after the closing of the Merger, Civista will take commercially reasonable steps to allow employees of Comunibanc and the Subsidiary Bank who continue as employees of Civista and its subsidiaries to participate in the Civista 401(k) Plan and to accept roll-overs of benefits from the Comunibanc 401(k) Plan to the Civista 401(k) Plan.

Termination of ESOP: Comunibanc is required to terminate the ESOP effective as of the date immediately preceding to the effective time of the Merger. At the Effective Time, any remaining Comunibanc common shares held in the ESOP shall be converted into the right to receive, without interest, the Merger Consideration. Within sixty (60) days following the effective time, Civista and the ESOP Trustee shall arrange to request from the IRS a determination that the termination of the ESOP is in compliance with Sections 401(a) and 409 of the Code. Civista and the ESOP Trustee shall arrange to make partial distributions of up to 75% of the account balances

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credited to the ESOP participants as of the effective date (taking into account that portion of the Merger Consideration received by the ESOP on the effective date) as soon as administratively practicable after the effective date, with the remaining portion to be distributed as soon as administratively practicable after receipt by Civista of the ESOP determination letter.

Termination of Additional Comunibanc Employee Benefit Plans. On or prior to the effective date, Comunibanc is required to terminate and pay all accrued benefit amounts to the respective participants under (i) the Henry County Bank Director Supplemental Retirement Program, (ii) the Henry County Bank Salary Reduction Deferred Compensation Plan, and (iii) the Director Deferred Fee Plan. Additionally, on or prior to the effective date Civista will take all actions necessary to assume and thereafter discharge each respective split dollar agreement with certain executives and directors under (i) the Split Dollar Life Insurance Agreement & Endorsement Method Split Dollar Plan – Executives and (ii) the Split Dollar Life Insurance Agreement & Endorsement Method Split Dollar Plan – Directors.

NASDAQ Stock Listing

Civista’s common shares currently are listed on the Nasdaq Capital Market^® under the symbol “CIVB.” The shares to be issued to Comunibanc shareholders as Merger Consideration also will be eligible for trading on the NASDAQ. Civista will list, prior to the Effective Time, the Civista common shares to be issued pursuant to the Merger.

Conditions to Consummation of the Merger

Conditions of Civista and Comunibanc. The respective obligations of Civista and Comunibanc to complete the Merger are subject to the fulfillment or written waiver of each of the following conditions:

Conditions of Comunibanc. Comunibanc will not be required to complete the Merger unless the following conditions are fulfilled or waived in writing:

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Conditions of Civista. Civista will not be required to consummate the Merger unless the following conditions are also fulfilled or waived in writing:

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Representations and Warranties

Comunibanc has made customary representations and warranties in the Merger Agreement relating to:

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