OGE Energy (OGE) 424B2Prospectus for primary offering

This prospectus supplement is a supplement to the accompanying prospectus that also is a part of this document. The accompanying prospectus is part of a registration statement that we filed with the SEC using a “shelf” registration process. Under this process, we may sell an unspecified amount of the securities described in the accompanying prospectus, of which this offering is a part. This prospectus supplement provides you with specific information about the terms of this offering. Both this prospectus supplement and the accompanying prospectus include important information about us, our Senior Notes and other information you should know before investing in our Senior Notes. This prospectus supplement also adds, updates and changes information contained in the accompanying prospectus. To the extent that any statement that we make in this prospectus supplement is inconsistent with the statements made in the accompanying prospectus, the statements made in the accompanying prospectus are deemed modified or superseded by the statements made in this prospectus supplement. You should read both this prospectus supplement and the accompanying prospectus together with the additional information described under the heading “Where You Can Find More Information” in this prospectus supplement before investing in our Senior Notes. For more details, you should read the exhibits filed with the registration statement of which this prospectus supplement and the accompanying prospectus are a part.

Except for the historical statements contained herein and therein, the matters discussed in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference are forward-looking statements that are not historical fact and constitute “forward-looking statements.” Such forward-looking statements are intended to be identified in this document by the words “anticipate,” “believe,” “estimate,” “expect,” “intend,” “objective,” “plan,” “possible,” “potential,” “project,” “target” and similar expressions. Forward-looking statements are not guarantees of performance. They involve risks, uncertainties and assumptions. Actual results may vary materially from those expressed in forward-looking statements. In addition to the specific risk factors discussed in “Risk Factors” in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference, factors that could cause actual results to differ materially from the forward -looking statements include, but are not limited to:

The Indenture under which the Senior Notes will be issued will not prevent us from incurring additional indebtedness, which may be secured by some or all of our assets. As of the date of this prospectus supplement, we do not have any plans to issue secured indebtedness. The Senior Notes will not have the benefit of any financial or other restrictive covenants.

We may, from time to time, without the consent of the holders of the Senior Notes offered by this prospectus supplement, reopen the Senior Notes and issue additional Senior Notes with the same terms (including maturity and interest payment terms), except for the date of issue, the price to public, and, if applicable, the first date from which interest will accrue and the initial interest payment date, as the Senior Notes offered by this prospectus supplement. Any such additional Senior Notes, together with the Senior Notes offered by this prospectus supplement, are intended to constitute a single series under the Indenture and will be part of the same issue as the Senior Notes offered by this prospectus supplement for U.S. federal income tax purposes if such additional issuance is fungible with this issuance for U.S. federal income tax purposes.

We may redeem the Senior Notes at any time on or after November 26, 2021 at a price equal to 100% of the principal amount of the Senior Notes being redeemed, plus any accrued and unpaid interest thereon, if any, to, but excluding, the redemption date.

We will mail a notice of redemption to each holder of the Senior Notes by first-class mail at least 30 and not more than 60 days prior to the date fixed for redemption. Unless we default on payment of the redemption price, interest will cease to accrue on the Senior Notes or portions thereof called for redemption. If fewer than all of the Senior Notes are to be redeemed, the Trustee will select, not more than 60 days prior to the date fixed for redemption, the particular Senior Notes or portions thereof for redemption from the outstanding Senior Notes not previously called by such method as the Trustee deems fair and appropriate.

For information regarding DTC and DTC’s procedures, see “Book-Entry System” in the accompanying prospectus. Clearstream has advised us that it is incorporated under the laws of Luxembourg as a professional depositary. Clearstream holds securities for its customers and facilitates the clearance and settlement of securities transactions between its customers through electronic book-entry changes in accounts of its customers, thereby eliminating the need for physical movement of certificates. Clearstream provides to its customers, among other things, services for safekeeping, administration, clearance and settlement of internationally traded securities and securities lending and borrowing. Clearstream interfaces with domestic markets in several countries. As a professional depositary, Clearstream is subject to regulation by the Luxembourg Commission for the Supervision of the Financial Section. Clearstream customers are recognized financial institutions around the world, including underwriters, securities brokers and dealers, banks, trust companies, clearing corporations and other organizations and may include the underwriters. Indirect access to Clearstream is also available to others, such as banks, brokers, dealers and trust companies that clear through or maintain a custodial relationship with a Clearstream customer either directly or indirectly.

Euroclear has advised us that it was created in 1968 to hold securities for participants of Euroclear and to clear and settle transactions between Euroclear participants through simultaneous electronic book-entry delivery against payment, thereby eliminating the need for physical movement of certificates and any risk from lack of simultaneous transfers of securities and cash. Euroclear provides various other services, including securities lending and borrowing and interfaces with domestic markets in several countries. Euroclear is operated by the Euroclear Operator, under contract with Euroclear Clearance Systems S.C., a Belgian cooperative corporation (the “Cooperative”). All operations are conducted by the Euroclear Operator, and all Euroclear securities clearance accounts and Euroclear cash accounts are accounts with the Euroclear Operator, not the Cooperative. The Cooperative establishes policy for Euroclear on behalf of Euroclear participants. Euroclear participants include banks (including central banks), securities brokers and dealers, and other professional financial intermediaries and may include the underwriters. Indirect access to Euroclear is also available to other firms that clear through or maintain a custodial relationship with a Euroclear participant, either directly or indirectly.

The Euroclear Operator has advised us that it is licensed by the Belgian Banking and Finance Commission to carry out banking activities on a global basis. As a Belgian bank, it is regulated and examined by the Belgian Banking and Finance Commission.

We have provided the descriptions of the operations and procedures of DTC, Clearstream and Euroclear in this prospectus supplement and the accompanying prospectus solely as a matter of convenience. These operations and procedures are solely within the control of those organizations and are subject to change by them from time to time. None of us, the underwriters or the trustee takes any responsibility for these operations or procedures, and you are urged to contact DTC, Clearstream and Euroclear or their participants directly to discuss these matters.

Although DTC, Clearstream and Euroclear have agreed to the procedures provided below in order to facilitate transfers, they are under no obligation to perform these procedures, and these procedures may be modified or discontinued at any time.

Payments on the Senior Notes represented by the global notes will be made to DTC or its nominee, as the case may be, as the registered owner thereof. We expect that DTC or its nominee, upon receipt of any payment on the Senior Notes represented by a global note, will credit participants’ accounts with payments in amounts proportionate to their respective beneficial interests in the global note as shown in the records of DTC or its nominee. We also expect that payments by participants to owners of beneficial interests in the global note held through such participants will be governed by standing instructions and customary

Distributions on the Senior Notes held beneficially through Clearstream will be credited to cash accounts of its customers in accordance with its rules and procedures, to the extent received by the U.S. depositary for Clearstream.

Securities clearance accounts and cash accounts with the Euroclear Operator are governed by the Terms and Conditions Governing Use of Euroclear and the related Operating Procedures of the Euroclear System, and applicable Belgian law (collectively, the “Terms and Conditions”). The Terms and Conditions govern transfers of securities and cash within Euroclear, withdrawals of securities and cash from Euroclear, and receipts of payments with respect to securities in Euroclear. All securities in Euroclear are held on a fungible basis without attribution of specific certificates to specific securities clearance accounts. The Euroclear Operator acts under the Terms and Conditions only on behalf of Euroclear participants and has no record of or relationship with persons holding through Euroclear participants.

Distributions on the Senior Notes held beneficially through Euroclear will be credited to the cash accounts of its participants in accordance with the Terms and Conditions, to the extent received by the U.S. depositary for Euroclear.

Initial settlement for the Senior Notes will be made in immediately available funds. Secondary market trading between DTC participants will occur in the ordinary way in accordance with DTC rules and will be settled in immediately available funds. Secondary market trading between Clearstream customers and/or Euroclear participants will occur in the ordinary way in accordance with the applicable rules and operating procedures of Clearstream and Euroclear, as applicable, and will be settled using the procedures applicable to conventional eurobonds in immediately available funds.

Cross-market transfers between persons holding directly or indirectly through DTC, on the one hand, and directly or indirectly through Clearstream customers or Euroclear participants, on the other hand, will be effected through DTC in accordance with DTC rules on behalf of the relevant European international clearing system by the U.S. depositary; however, such cross-market transactions will require delivery of instructions to the relevant European international clearing system by the counterparty in such system in accordance with its rules and procedures and within its established deadlines (European time). The relevant European international clearing system will, if the transaction meets its settlement requirements, deliver instructions to the U.S. depositary to take action to effect final settlement on its behalf by delivering or receiving the Senior Notes in DTC, and making or receiving payment in accordance with normal procedures for same-day funds settlement applicable to DTC. Clearstream customers and Euroclear participants may not deliver instructions directly to their U.S. depositaries.

Because of time-zone differences, credits of the Senior Notes received in Clearstream or Euroclear as a result of a transaction with a DTC participant will be made during subsequent securities settlement processing and dated the business day following the DTC settlement date. Such credits or any transactions in the Senior Notes settled during such processing will be reported to the relevant Clearstream customers or Euroclear participants on such business day. Cash received in Clearstream or Euroclear as a result of sales of the Senior Notes by or through a Clearstream customer or a Euroclear participant to a DTC participant will be received with value on the DTC settlement date but will be available in the relevant Clearstream or Euroclear cash account only as of the business day following settlement in DTC.

The following discussion is a summary of certain U.S. federal income tax consequences relevant to the purchase, beneficial ownership and disposition of the Senior Notes offered by this prospectus supplement. This summary is based on the U.S. Internal Revenue Code of 1986, as amended, or the “Code”, Treasury regulations promulgated thereunder, or “Treasury Regulations”, administrative pronouncements of the U.S. Internal Revenue Service, or “IRS”, and judicial decisions, all as currently in effect and all of which are subject to change and to different interpretations. Changes to any of the foregoing authorities could apply on a retroactive basis, and could affect the U.S. federal income tax consequences described below. We will not

This summary does not address all of the U.S. federal income tax considerations that may be relevant to a particular investor’s circumstances (including the effects of Section 451 of the Code with respect to conforming the timing of income accruals to financial statements) and does not discuss any aspect of U.S. federal tax law other than income tax law or any state, local or non-U.S. tax consequences of the purchase, beneficial ownership and disposition of the Senior Notes. This summary addresses only Senior Notes purchased for cash pursuant to this offering at their “issue price” ​(generally, the first price at which a substantial amount of the Senior Notes is sold for cash to investors (excluding sales to bond houses, brokers or similar persons or organizations acting in the capacity as underwriters, placement agents or wholesalers)) and does not address U.S. federal income tax considerations applicable to investors that may be subject to special tax rules, such as:

As used herein, a “U.S. Holder” is a beneficial owner of Senior Notes that is, for U.S. federal income tax purposes, (i) an individual citizen or resident of the United States, (ii) a corporation created or organized in or under the laws of the United States, any state thereof or the District of Columbia, (iii) an estate whose income is subject to U.S. federal income tax regardless of its source, or (iv) a trust if (A) a United States court has the authority to exercise primary supervision over the administration of the trust and one or more U.S. persons (as defined in the Code) are authorized to control all substantial decisions of the trust or (B) it has a valid election in place to be treated as a U.S. person.

A “Non-U.S. Holder” is any beneficial owner of the Senior Notes that is neither a U.S. Holder nor a partnership (including an entity or arrangement treated as a partnership for U.S. federal income tax purposes).

If a partnership (or other entity or arrangement treated as a partnership for U.S. federal income tax purposes) holds Senior Notes, the U.S. federal income tax treatment of a partner will generally depend on the status of the partner and the activities of the partnership. A partnership holding Senior Notes, and partners in such a partnership, should consult their own tax advisors with regard to the U.S. federal income tax consequences of the purchase, ownership and disposition of the Senior Notes by the partnership.

THE DISCUSSION OF CERTAIN U.S. FEDERAL INCOME TAX CONSEQUENCES OF THE PURCHASE, OWNERSHIP AND DISPOSITION OF THE SENIOR NOTES IS NOT INTENDED TO BE, NOR SHOULD IT BE CONSTRUED TO BE, LEGAL OR TAX ADVICE TO ANY PARTICULAR PERSON. ACCORDINGLY, ALL PROSPECTIVE INVESTORS ARE URGED TO CONSULT THEIR

The certification requirement referred to above will be fulfilled if (i) the beneficial owner of the Senior Notes certifies on a properly executed IRS Form W-8BEN or W-8BEN-E, as applicable, or applicable successor form, under penalties of perjury, that such beneficial owner is not a U.S. person, provides its name and address and certifies the other relevant factual information supporting its exemption, and (ii) the beneficial owner provides the IRS Form W-8BEN or W-8BEN-E, as applicable, or applicable successor form with the paying agent, or in the case of Senior Notes held on behalf of the beneficial owner by a securities clearing organization, bank, or other financial institution holding customers’ securities in the ordinary course of its trade or business, such financial institution provides the paying agent a statement that it has received the IRS Form W-8BEN or W-8BEN-E, as applicable, or applicable successor form, from the beneficial owner and furnishes the paying agent with a copy.

Prospective investors should consult their tax advisors regarding possible additional reporting requirements.

(b)    A Non-U.S. Holder generally will not be subject to U.S. federal income tax on gain realized on the sale, redemption, retirement or other taxable disposition of the Senior Notes, unless:

If a Non-U.S. Holder is described in the first bullet in paragraph (b) above, such Non-U.S. Holder generally will be subject to U.S. federal income tax at a rate of 30% on the amount by which such Non-U.S. Holder’s capital gains allocable to United States sources, including gain from such disposition, exceed any capital losses allocable to United States sources, except as otherwise required by an applicable income tax treaty.

To the extent the amount realized on a sale, redemption, retirement or other taxable disposition of the Senior Notes is attributable to accrued but unpaid interest on the Senior Notes, this amount generally will be treated in the same manner as described in paragraph (a) above.

Any amounts withheld under the backup withholding rules will be allowed as a refund or a credit against a U.S. Holder’s U.S. federal income tax liability, provided the required information is furnished to the IRS on a timely basis. U.S. Holders should consult their tax advisors regarding the application of information reporting and backup withholding rules in their particular situations, the availability of an exemption therefrom and the procedure for obtaining such an exemption, if applicable.

Any amounts withheld under the backup withholding rules will be allowed as a refund or a credit against a Non-U.S. Holder’s U.S. federal income tax liability, provided the required information is furnished to the IRS on a timely basis. Non-U.S. Holders of Senior Notes should consult their tax advisors regarding the application of information reporting and backup withholding in their particular situations, the availability of an exemption therefrom, and the procedure for obtaining an exemption, if applicable.

Pursuant to the Foreign Account Tax Compliance Act, or “FATCA,” foreign financial institutions (which term includes most foreign banks, hedge funds, private equity funds, mutual funds, securitization vehicles and other investment vehicles) and certain other foreign entities generally must comply with certain information reporting rules with respect to their U.S. account holders and investors or confront a withholding tax on U.S.- source payments made to them (whether received as a beneficial owner or as an intermediary for another party). A foreign financial institution or such other foreign entity that does not comply with the FATCA reporting requirements will generally be subject to a 30% withholding tax with respect to any “withholdable payments.” For this purpose, withholdable payments generally include U.S.-source payments otherwise subject to nonresident withholding tax (including U.S.-source interest on the Senior Notes) and, subject to the proposed Treasury Regulations discussed below, also include the entire gross proceeds from the sale or other disposition of any debt instruments of U.S. issuers, even if the payment would otherwise not be subject to U.S. nonresident withholding tax (e.g., because it is capital gain). The IRS has issued proposed Treasury Regulations that would eliminate the application of this regime with respect to payments of gross proceeds (but not interest). Pursuant to these proposed Treasury Regulations, we and any other applicable withholding agent may (but are not required to) rely on this proposed change to FATCA withholding until final Treasury Regulations are issued or until such proposed Treasury Regulations are rescinded. Foreign financial institutions located in jurisdictions that have an intergovernmental agreement with the United States pursuant to FATCA may be subject to different rules with respect to information reporting and related requirements.

We will not pay any additional amounts to Non-U.S. Holders in respect of any amounts withheld, including pursuant to FATCA. Under certain circumstances, a Non-U.S. Holder might be eligible for refunds or credits of such taxes. Non-U.S. Holders are urged to consult with their own tax advisors regarding the effect, if any, of the FATCA provisions to them based on their particular circumstances.

Subject to the terms and conditions set forth in the underwriting agreement dated the date of this prospectus supplement, we have agreed to sell to each of the underwriters named below, for which J.P. Morgan Securities LLC, Mizuho Securities USA LLC, MUFG Securities Americas Inc., RBC Capital Markets, LLC, U.S. Bancorp Investments, Inc. and Wells Fargo Securities, LLC are acting as Representatives, and each of the underwriters has severally agreed to purchase from us, the respective amount of Senior Notes set forth opposite its name below:

The underwriters have advised us that they propose initially to offer the Senior Notes to the public at the public offering price set forth on the cover page of this prospectus supplement. They also may offer the Senior Notes to dealers at the public offering price less a concession not in excess of 0.15% of the principal amount of the Senior Notes. The underwriters may allow, and the dealers may reallow, a concession not in excess of 0.10% of the principal amount of the Senior Notes on sales to other dealers. After the initial offering of the Senior Notes to the public is completed, the underwriters may change the offering price.

The following table shows the underwriting discount that we will pay to the underwriters in connection with this offering of the Senior Notes.

Prior to this offering, there has been no public market for the Senior Notes. We do not intend to apply to list the Senior Notes on any securities exchange or to include the Senior Notes in any automated quotation system. The underwriters have informed us that they may make a market in the Senior Notes from time to time. The underwriters are under no obligation to make a market in the Senior Notes and any such market may be discontinued without notice.

In connection with the offering of the Senior Notes, the rules of the SEC permit the underwriters to engage in transactions that stabilize the price of the Senior Notes. These transactions may consist of bids or purchases for the purpose of pegging, fixing or maintaining the price of the Senior Notes. If the underwriters create a short position in the Senior Notes (that is, if they sell a larger principal amount of the Senior Notes than is set forth on the cover page of this prospectus supplement), the underwriters may reduce that short position by purchasing Senior Notes in the open market.

In general, purchases of a security for the purpose of stabilization or to reduce a short position could cause the price of the security to be higher than it might otherwise be in the absence of those purchases. Neither we nor any of the underwriters can predict the direction or magnitude of any effect that the transactions described above may have on the price of the Senior Notes. In addition, neither we nor any of

We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act of 1933, as amended. Alternatively, we may be required to contribute to payments that the underwriters may be required to make as a result of these liabilities.

It is expected that delivery of the Senior Notes will be made against payment therefor on or about the date specified on the cover page of this prospectus supplement, which is the third business day following the date of this prospectus supplement (such settlement cycle being referred to as “T+3”). Under Rule 15c6-1 under the Securities Exchange Act of 1934, trades in the secondary market generally are required to settle in two business days unless the parties to any such trade expressly agree otherwise. Accordingly, purchasers who wish to trade the Senior Notes on the date of this prospectus supplement will be required, by virtue of the fact that the Senior Notes initially will settle in T+3, to specify an alternative settlement cycle at the time of any such trade to prevent failed settlement. Purchasers of the Senior Notes who wish to trade the Senior Notes on the date of this prospectus supplement should consult their own advisors.

The underwriters and their respective affiliates are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, investment research, principal investment, hedging, financing and brokerage activities. In the ordinary course of their respective businesses, the underwriters and their affiliates have provided, and may in the future provide, investment banking, advisory or commercial banking services to us and our affiliates for which they have received, or may receive, customary fees and expenses. Affiliates of certain of the underwriters are participants in our credit facility and some of OGE Energy’s credit facilities. BOK Financial Securities, Inc., one of the underwriters, is an affiliate of BOKF, NA, the Trustee under the Indenture.

In addition, in the ordinary course of their business activities, the underwriters and their affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers. Such investments and securities activities may involve securities and/or instruments of ours or our affiliates. Underwriters or their affiliates that have a lending relationship with us, if any, may hedge their credit exposure to us consistent with their customary risk management policies. Typically, such underwriters and their respective affiliates would hedge such exposure by entering into transactions which consist of either the purchase of credit default swaps or the creation of short positions in our securities, including potentially the Senior Notes offered hereby. Any such credit default swaps or short positions could adversely affect future trading prices of the Senior Notes offered hereby. The underwriters and their affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financial instruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

The Senior Notes are not intended to be offered, sold or otherwise made available to and should not be offered, sold or otherwise made available to any retail investor in the European Economic Area (“EEA”). For these purposes, a retail investor means a person who is one (or more) of: (i) a retail client as defined in point (11) of Article 4(1) of Directive 2014/65/EU (as amended, “MiFID II”); or (ii) a customer within the meaning of Directive 2016/97/EU, where that customer would not qualify as a professional client as defined in point (10) of Article 4(1) of MiFID II; or (iii) not a qualified investor as defined in Regulation 2017/1129/EU (as amended, the “Prospectus Regulation”). No key information document required by Regulation (EU) No 1286/2014 (as amended, the “PRIIPs Regulation”) for offering or selling the Senior Notes or otherwise making them available to retail investors in the EEA has been prepared. Offering or selling the Senior Notes or otherwise making them available to any retail investor in the EEA may be unlawful under the PRIIPs Regulation. This prospectus supplement and the accompanying prospectus have been prepared on the basis that any offer of the Senior Notes in any Member State of the EEA will be made pursuant to an exemption under the Prospectus Regulation from the requirement to publish a

For the purposes of this provision, the expression an “offer to the public” in relation to any Senior Notes in any Member State of the EEA means the communication in any form and by any means of sufficient information on the terms of the offer and any Senior Notes to be offered so as to enable an investor to decide to purchase any Senior Notes.

The Senior Notes are not intended to be offered, sold or otherwise made available to and should not be offered, sold or otherwise made available to any retail investor in the United Kingdom (“UK”). For these purposes, a retail investor means a person who is one (or more) of: (i) a retail client, as defined in point (8) of Article 2 of Regulation (EU) No 2017/565 as it forms part of domestic law by virtue of the European Union (Withdrawal) Act 2018 (as amended, “EUWA”); (ii) a customer within the meaning of the provisions of the Financial Services and Markets Act 2000 (as amended, the “FSMA”) and any rules or regulations made under the FSMA to implement Directive (EU) 2016/97, where that customer would not qualify as a professional client, as defined in point (8) of Article 2(1) of Regulation (EU) No 600/2014 as it forms part of domestic law by virtue of the EUWA; or (iii) not a qualified investor as defined in Article 2 of Regulation 2017/1129/EU as it forms part of domestic law by virtue of the EUWA (the “UK Prospectus Regulation”). Consequently no key information document required by Regulation (EU) No 1286/2014 as it forms part of domestic law by virtue of the EUWA (the “UK PRIIPs Regulation”) for offering or selling the Senior Notes or otherwise making them available to retail investors in the UK has been prepared and therefore offering or selling the Senior Notes or otherwise making them available to any retail investor in the UK may be unlawful under the UK PRIIPs Regulation. This prospectus supplement and the accompanying prospectus have been prepared on the basis that any offer of Senior Notes in the United Kingdom will be made pursuant to an exemption under the UK Prospectus Regulation from the requirement to publish a prospectus. This prospectus supplement and the accompanying prospectus are not prospectuses for the purposes of the UK Prospectus Regulation.

For the purposes of this provision, the expression an “offer to the public” in relation to any Senior Notes in the United Kingdom means the communication in any form and by any means of sufficient information on the terms of the offer and any Senior Notes to be offered so as to enable an investor to decide to purchase any Senior Notes.

In the United Kingdom, this prospectus supplement and the accompanying prospectus are being distributed only to, and are directed only at, and any offer subsequently made may only be directed at persons who are “qualified investors” ​(as defined in the UK Prospectus Regulation): (i) who have professional experience in matters relating to investments falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the “Order”) and/or (ii) who are high net worth companies (or persons to whom it may otherwise be lawfully communicated) falling within Article 49(2)(a) to (e) of the Order (all such persons together being referred to as “relevant persons”) or otherwise in circumstances which have not resulted and will not result in an offer to the public of the Senior Notes in the United Kingdom within the meaning of the FSMA. This prospectus supplement and the accompanying prospectus must not be acted on or relied on in the United Kingdom by persons who are not relevant persons. In the United Kingdom, any investment or investment activity to which this prospectus supplement and the accompanying prospectus relates is only available to, and will be engaged in with, relevant persons.

Each underwriter has represented, warranted and agreed that: it has only communicated or caused to be communicated and will only communicate or cause to be communicated an invitation or inducement to engage in investment activity (within the meaning of Section 21 of the FSMA) received by it in connection with the issue or sale of any Senior Notes which are the subject of the offering contemplated by the prospectus supplement and the accompanying prospectus in circumstances in which Section 21(1) of the FSMA does not apply to the Company; and it has complied and will comply with all applicable provisions of the FSMA with respect to anything done by it in relation to the Senior Notes in, from or otherwise involving the United Kingdom.

Securities legislation in certain provinces or territories of Canada may provide a purchaser with remedies for rescission or damages if this prospectus supplement or the accompanying prospectus (including any amendment hereto or thereto) contains a misrepresentation, provided that the remedies for rescission or damages are exercised by the purchaser within the time limit prescribed by the securities legislation of the purchaser’s province or territory. The purchaser should refer to any applicable provisions of the securities legislation of the purchaser’s province or territory for particulars of these rights or consult with a legal advisor.

Pursuant to section 3A.3 of National Instrument 33-105 Underwriting Conflicts (NI 33-105), the underwriters are not required to comply with the disclosure requirements of NI 33-105 regarding underwriter conflicts of interest in connection with this offering.

The Senior Notes have not been and may not and will not be offered or sold in Hong Kong, by means of any document, other than (i) to “professional investors” as defined in the Securities and Futures Ordinance (Cap. 571, Laws of Hong Kong) and any rules made thereunder, or (ii) in other circumstances which do not result in the document being a “prospectus” as defined in the Companies (Winding Up and Miscellaneous Provisions) Ordinance (Cap. 32, Laws of Hong Kong) or which do not constitute an offer to the public within the meaning of that Ordinance. No advertisement, invitation or document relating to the Senior Notes has been, may be or will be issued or has been, may be or will be in the possession of any person for the purpose of issue (in each case whether in Hong Kong or elsewhere), which is directed at, or the contents of which are likely to be accessed or read by, the public of Hong Kong (except if permitted to do so under the securities laws of Hong Kong) other than with respect to Senior Notes which are or are intended to be disposed of only to persons outside Hong Kong or only to “professional investors” as defined in the Securities and Futures Ordinance (Cap. 571, Laws of Hong Kong) and any rules made thereunder.

This prospectus supplement and the accompanying prospectus have not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, this prospectus and any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of the Senior Notes may not be circulated or distributed, nor may the Senior Notes be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to persons in Singapore other than (i) to an institutional investor as defined in Section 4A of the Securities and Futures Act, Chapter 289 of Singapore, as modified from time to time (the “SFA”), pursuant to Section 274 of the SFA, (ii) to a relevant person (as defined in Section 275(2) of the SFA) pursuant to Section 275(1) of the SFA, or any person pursuant to Section 275(1A) of the SFA, and in accordance with the conditions specified in Section 275, of the SFA, or (iii) otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA.

Where the Senior Notes are subscribed or purchased under Section 275 of the SFA by a relevant person which is:

Solely for the purposes of our obligations pursuant to sections 309B of the SFA and the Securities and Futures (Capital Markets Products) Regulations 2018 of Singapore (the “CMP Regulations 2018”), we have determined, and hereby notify all relevant persons (as defined in Section 309A(1) of the SFA) that the Senior Notes are “prescribed capital markets products” ​(as defined in the CMP Regulations 2018) and Excluded Investment Products (as defined in MAS Notice SFA 04-N12: Notice on the Sale of Investment Products and MAS Notice FAA-N16: Notice on Recommendations on Investment Products).

The Senior Notes have not been and will not be registered or filed with, or approved by, the Financial Supervisory Commission of Taiwan, Republic of China and/or any other regulatory authority of Taiwan

The Senior Notes have not been, and are not being, publicly offered, sold, promoted or advertised in the United Arab Emirates (including the Dubai International Financial Centre) other than in compliance with the laws of the United Arab Emirates (and the Dubai International Financial Centre) governing the issue, offering and sale of securities. Further, this prospectus supplement and the accompanying prospectus do not constitute a public offer of securities in the United Arab Emirates (including the Dubai International Financial Centre) and are not intended to be a public offer. This prospectus supplement and the accompanying prospectus have not been approved by or filed with the Central Bank of the United Arab Emirates, the Securities and Commodities Authority or the Dubai Financial Services Authority.

Certain of the underwriters or their affiliates may be lenders under our Term Loan Facility that we intend to repay using, in part, the net proceeds of this offering. In such event, it is possible that one or more of the underwriters or their affiliates could receive at least 5% of the net proceeds of the offering, and in that case such underwriter would be deemed to have a conflict of interest under FINRA Rule 5121 (Public Offerings of Securities with Conflicts of Interest). In the event of any such conflict of interest, such underwriter would be required to conduct the distribution of the Senior Notes in accordance with FINRA Rule 5121. If FINRA Rule 5121 is applicable, such underwriter would not be permitted to confirm a sale to an account over which it exercises discretionary authority without first receiving specific written approval from the account holder.

Except for the historical statements contained herein and therein, the matters discussed in this prospectus and the documents incorporated by reference are forward-looking statements that are not historical fact and constitute “forward-looking statements.” Such forward-looking statements are intended to be identified in this document by the words “anticipate,” “believe,” “estimate,” “expect,” “intend,” “objective,” “plan,” “possible,” “potential,” “project,” “target” and similar expressions. Forward-looking statements are not guarantees of performance. They involve risks, uncertainties and assumptions. Our future results may differ materially from those expressed in these forward-looking statements. These statements are necessarily based upon various assumptions involving judgments with respect to the future and other risks, including, among others:

Under our Restated Certificate of Incorporation, we are authorized to issue 450,000,000 shares of common stock, par value $0.01 per share, of which 200,173,981 shares were outstanding on March 31, 2021.

We are also authorized to issue 5,000,000 shares of preferred stock, par value $0.01 per share. No shares of preferred stock are currently outstanding. Without shareholder approval, we may issue preferred stock in the future in such series as may be designated by our board of directors. In creating any such series, our board of directors has the authority to fix the rights and preferences of each series with respect to, among other things, the dividend rate, redemption provisions, liquidation preferences, sinking fund provisions, conversion rights and voting rights. The terms of any series of preferred stock that we may issue in the future may provide the holders of such preferred stock with rights that are senior to the rights of the holders of our common stock.

Before we can pay any dividends on our common stock, the holders of our preferred stock that may be outstanding are entitled to receive their dividends at the respective rates as may be provided for the shares of their series. Currently, there are no shares of our preferred stock outstanding. Because we are a holding company and conduct all of our operations through our subsidiaries, our cash flow and ability to pay dividends will be dependent on the earnings and cash flows of our subsidiaries and other equity interests and the distribution or other payment of those earnings to us in the form of dividends or distributions, or in the form of repayments of loans or advances to us. We expect to derive principally all of the funds required by us to enable us to pay dividends on our common stock from dividends paid by OG&E, on OG&E’s common stock, and from distributions paid by OGE Holdings, on OGE Enogex Holdings limited liability company interests, including distributions from its interest in Enable. Our ability to receive dividends on OG&E’s common stock is subject to the prior rights of the holders of any OG&E preferred stock that may be outstanding, any covenants of OG&E’s certificate of incorporation and OG&E’s debt instruments limiting the ability of OG&E to pay dividends and the ability of public utility commissions that regulate OG&E to effectively restrict the payment of dividends by OG&E. Our ability to receive distributions from our interest in Enable is subject to the prior rights of existing and future holders of limited partnership interests that may be outstanding and any covenants in the debt instruments of Enable and its subsidiaries and equity interests limiting the ability to pay distributions.

Each holder of common stock is entitled to one vote per share upon all matters upon which shareowners have the right to vote and generally will vote together as one class. Our board of directors has the authority to fix conversion and voting rights for any new series of preferred stock (including the right to elect directors upon a failure to pay dividends), provided that no share of preferred stock can have more than one vote per share.

Our Restated Certificate of Incorporation also contains “fair price” provisions, which require the approval by the holders of at least 80 percent of the voting power of our outstanding voting stock as a condition for mergers, consolidations, sales of substantial assets, issuances of capital stock and certain other business combinations and transactions involving us and any substantial (10 percent or more) holder of our voting stock unless the transaction is either approved by a majority of the members of our board of directors who are unaffiliated with the substantial holder or specified minimum price and procedural requirements are met. The provisions summarized in the foregoing sentence may be amended only by the

Any special U.S. Federal income tax considerations applicable to Debt Securities sold at an original issue discount and any special U.S. Federal income tax or other considerations applicable to any Debt Securities that are denominated in a currency other than U.S. dollars will be described in the prospectus supplement relating to that series of Debt Securities.

Unless we indicate otherwise in the applicable prospectus supplement, the Debt Securities will be denominated in U.S. dollars in minimum denominations of $1,000 and integral multiples of $1,000 in excess thereof.

Unless we indicate otherwise in the applicable prospectus supplement, there will be no provisions in the Indenture or the Debt Securities that require us to redeem, or permit the holders to cause a redemption or repurchase of, the Debt Securities or that otherwise protect the holders in the event that we incur substantial additional indebtedness, whether or not in connection with a change in control of our company.

Debt Securities of any series may be exchanged for other Debt Securities of the same series of any authorized denominations and of a like aggregate principal amount, stated maturity and original issue date. (Section 2.06 of the Indenture.)

default in the payment of interest on any Note issued under the Indenture when due and continuance of that default for 30 days;

Unless we indicate otherwise in the applicable prospectus supplement, we and the Trustee may modify and amend the Indenture and the Debt Securities from time to time. Depending upon the type of amendment, we may not need the consent or approval of any of the holders of the Notes, or we may need either the consent or approval of the holders of a majority in principal amount of the outstanding Notes or the consent or approval of each holder affected by the proposed amendment.

We will need the consent of the holders of each outstanding Note affected by a proposed amendment if the amendment would cause any of the following to occur:

Amendments other than those described in the above two paragraphs will require the approval of a majority in principal amount of the outstanding Notes.

We may be discharged from all obligations relating to the Notes and the Indenture (except for specified obligations such as obligations to register the transfer or exchange of Notes, replace stolen, lost or mutilated Notes and maintain paying agencies) if we irrevocably deposit with the Trustee, in trust for the benefit of holders of Notes, money or U.S. government obligations, or any combination thereof, sufficient to make all payments of principal, premium and interest on the Notes on the dates those payments are due. To discharge those obligations, we must deliver to the Trustee an opinion of counsel that the holders of the Notes will not recognize income, gain or loss for U.S. Federal income tax purposes as a result of the defeasance or discharge of the Indenture. If we discharge our obligations as described above, the holders of Notes must look only to the funds deposited with the Trustee, and not us, for payments on the Notes. (Section 4.01 of the Indenture.)

We will not merge into any other corporation or sell or otherwise transfer all or substantially all our assets unless the successor or transferee corporation assumes by supplemental indenture our obligations to pay the principal, interest and any premium on all the Notes and our obligation to perform every covenant in the Indenture that we are supposed to perform or observe. Upon any merger, sale or transfer of all or substantially all of our assets, the successor or transferee corporation will succeed to, and be substituted for, and may exercise all of our rights and powers under the Indenture with the same effect as if the successor

Unless we indicate otherwise in the applicable prospectus supplement, The Depository Trust Company (“DTC”), New York, New York, will act as securities depository for the Debt Securities. The Debt Securities will be issued as fully-registered securities registered in the name of Cede & Co., DTC’s partnership nominee, or such other name as may be requested by an authorized representative of DTC. One fully-registered certificate will be issued for each issue of Debt Securities, each in the aggregate principal amount of any such issue, and will be deposited with DTC. If, however, the aggregate principal amount of any issue exceeds $500 million, one certificate will be issued with respect to each $500 million of principal amount, and an additional certificate will be issued with respect to any remaining principal amount of any such issue.

DTC, the world’s largest securities depository, is a limited-purpose trust company organized under the New York Banking Law, a “banking organization” within the meaning of the New York Banking Law, a member of the Federal Reserve System, a “clearing corporation” within the meaning of the New York Uniform Commercial Code and a “clearing agency” registered pursuant to the provisions of Section 17A of the Securities Exchange Act of 1934. DTC holds and provides asset servicing for issues of U.S. and non-U.S. equity issues, corporate and municipal debt issues and money market instruments that DTC’s participants (“Direct Participants”) deposit with DTC. DTC also facilitates the post-trade settlement among Direct Participants of sales and other securities transactions in deposited securities, through electronic computerized book-entry transfers and pledges between Direct Participants’ accounts. This eliminates the need for physical movement of securities certificates. Direct Participants include both U.S. and non-U.S. securities brokers and dealers, banks, trust companies, clearing corporations and certain other organizations. DTC is a wholly-owned subsidiary of The Depository Trust & Clearing Corporation (“DTCC”). DTCC is the holding company for DTC, National Securities Clearing Corporation and Fixed Income Clearing Corporation, all of which are registered clearing agencies. DTCC is owned by the users of its regulated subsidiaries. Access to the DTC system is also available to others such as both U.S. and non-U.S. securities brokers and dealers, banks, trust companies and clearing corporations that clear through or maintain a custodial relationship with a Direct Participant, either directly or indirectly (“Indirect Participants”). The DTC Rules applicable to its Participants are on file with the SEC. More information about DTC can be found at www.dtcc.com.

Purchases of Debt Securities under the DTC system must be made by or through Direct Participants, which will receive a credit for the Debt Securities on DTC’s records. The ownership interest of each actual purchaser of each Debt Security (“Beneficial Owner”) is in turn to be recorded on the Direct and Indirect Participants’ records. Beneficial Owners will not receive written confirmation from DTC of their purchase. Beneficial Owners are, however, expected to receive written confirmations providing details of the transaction, as well as periodic statements of their holdings, from the Direct or Indirect Participant through which the Beneficial Owner entered into the transaction. Transfers of ownership interests in the Debt Securities are to be accomplished by entries made on the books of Direct and Indirect Participants acting on behalf of Beneficial Owners. Beneficial Owners will not receive certificates representing their ownership interests in Debt Securities, except in the event that use of the book-entry system for the Debt Securities is discontinued.

To facilitate subsequent transfers, all Debt Securities deposited by Direct Participants with DTC are registered in the name of DTC’s partnership nominee, Cede & Co., or such other name as may be requested by an authorized representative of DTC. The deposit of Debt Securities with DTC and their registration in the name of Cede & Co. or such other DTC nominee do not effect any change in beneficial ownership. DTC has no knowledge of the actual Beneficial Owners of the Debt Securities; DTC’s records reflect only the identity of the Direct Participants to whose accounts such Debt Securities are credited, which may or may not be the Beneficial Owners. The Direct and Indirect Participants will remain responsible for keeping account of their holdings on behalf of their customers.

Conveyance of notices and other communications by DTC to Direct Participants, by Direct Participants to Indirect Participants, and by Direct Participants and Indirect Participants to Beneficial Owners will be governed by arrangements among them, subject to any statutory or regulatory requirements as may be in effect from time to time. Beneficial Owners of Debt Securities may wish to take certain steps to augment the transmission to them of notices of significant events with respect to the Debt Securities, such as redemptions, tenders, defaults, and proposed amendments to the Debt Security documents. For example,

the purchase price of the Securities;

any underwriting discounts and other items constituting underwriters’ compensation; and

Agents, dealers and underwriters may be customers of, engage in transactions with, or perform services for us or our affiliates in the ordinary course of business.

Unless otherwise indicated in the applicable prospectus supplement, legal opinions relating to the Securities and certain other matters will be rendered by our counsel, GableGotwals, Tulsa, Oklahoma, and Jones Day, Chicago, Illinois. Unless otherwise indicated in the applicable prospectus supplement, GableGotwals will pass on matters pertaining to local laws and as to these matters other counsel will rely on their opinions.

Unless otherwise indicated in the applicable prospectus supplement, certain legal matters will be passed upon for any underwriters, dealers or agents named in a prospectus supplement by Chapman and Cutler LLP, Chicago, Illinois.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. Our SEC filings are available to the public over the Internet at the SEC’s web site at www.sec.gov.

The SEC allows us to “incorporate by reference” in this prospectus the information we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is an important part of this prospectus, and information that we file later with the SEC will automatically update and supersede the information contained in or incorporated by reference in this prospectus. We incorporate by reference the following documents:

We also incorporate by reference all future filings we make with the SEC under Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934 on or after the date of this prospectus until we sell all of the Securities referred to herein.