This summary highlights selected information in this joint proxy statement/prospectus and may not contain all of the information that is important to you. You should carefully read this entire joint proxy statement/prospectus and the other documents we refer you to for a more complete understanding of the matters being considered at the special meetings. In addition, we incorporate by reference important business and financial information about Huntington and Cadence into this joint proxy statement/prospectus. You may obtain the information incorporated by reference into this joint proxy statement/prospectus without charge by following the instructions in the section entitled “Where You Can Find More Information” beginning on page 162 of this joint proxy statement/prospectus.

Huntington is a multi-state diversified regional bank holding company headquartered in Columbus, Ohio. Founded in 1866, The Huntington National Bank and its affiliates provide consumers, small- and middle-market businesses, corporations, municipalities, and other organizations with a comprehensive suite of banking, payments, wealth management, and risk management products and services. Huntington operates over 1,000 full-service branches in 14 states and conducts select financial services and other activities in additional states. As of September 30, 2025, Huntington had consolidated total assets of approximately $210 billion, total loans and leases of approximately $138 billion, total deposits of approximately $165 billion and total shareholders’ equity of approximately $22 billion. Effective October 20, 2025, Huntington completed its previously announced acquisition of Veritex Holdings, Inc. (“Veritex”), a bank holding company headquartered in Dallas, Texas. As of September 30, 2025, Veritex had $12.8 billion in assets, including $9.6 billion in loans, and $10.8 billion in deposits.

Huntington’s common stock is traded on the NASDAQ under the symbol “HBAN.”

Huntington’s principal office is located at 41 South High Street, Columbus, Ohio 43287, and its telephone number at that location is (614) 480-2265.

Cadence is a Mississippi state-chartered bank headquartered in Houston, Texas, and Tupelo, Mississippi. Cadence offers comprehensive banking, investment, trust and mortgage products and services to meet the needs of individuals, businesses and corporations. Cadence operates more than 390 commercial banking and mortgage locations in Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, Missouri, Tennessee and Texas. As of September 30, 2025, Cadence had total assets of $53.3 billion; total loans, net of unearned income, of $36.8 billion; total deposits of $43.9 billion; and shareholders’ equity of $6.1 billion.

Cadence’s common stock and preferred stock are traded on the New York Stock Exchange (the “NYSE”) under the symbols “CADE” and “CADE-PrA,” respectively.

Cadence’s principal office is located at One Mississippi Plaza, 201 South Spring Street, Tupelo, Mississippi 38804, and its telephone number at that location is (662) 680-2000.

The terms and conditions of the merger are contained in the merger agreement, a copy of which is attached as Annex A to this joint proxy statement/prospectus. You are encouraged to read the merger agreement carefully and in its entirety, as it is the primary legal document that governs the merger.

Subject to the terms and conditions of the merger agreement, at the completion of the merger, Cadence will merge with and into The Huntington National Bank (“Huntington National Bank”), a wholly owned bank subsidiary of Huntington, with Huntington National Bank as the surviving bank. Following the merger, Cadence common stock and Cadence series A preferred stock will be delisted from the NYSE and deregistered under the Exchange Act and will cease to be publicly traded.

In the merger, holders of Cadence common stock will receive 2.475 shares of Huntington common stock for each share of Cadence common stock they hold immediately prior to the effective time. Huntington will not issue any fractional shares of Huntington common stock in the merger. Holders of Huntington common stock who would otherwise be entitled to a fraction of a share of Huntington common stock in the merger will instead receive, for the fraction of a share, an amount in cash (rounded to the nearest cent) based on the Huntington share closing price.

Huntington common stock is listed on the NASDAQ under the symbol “HBAN,” and Cadence common stock is listed on the NYSE under the symbol “CADE.” The following table shows the closing sale prices of Huntington common stock and Cadence common stock as reported on the NASDAQ and the NYSE, respectively, on October 24, 2025, the last full trading day before the public announcement of the merger agreement, and on [   ], 2025, the last practicable trading day before the date of this joint proxy statement/prospectus. This table also shows the implied value of the merger consideration to be issued in exchange for each share of Cadence common stock, which was calculated by multiplying the closing price of Huntington common stock on those dates by the exchange ratio of 2.475.

For more information on the exchange ratio, see the section entitled “The Merger—Terms of the Merger” beginning on page 54 and the section entitled “The Merger Agreement—Merger Consideration” beginning on page 102.

In the merger, each share of Cadence series A preferred stock issued and outstanding immediately prior to the effective time will automatically be converted into the right to receive one (1) depositary share representing one one-thousandth (1/1000th) of a share of new Huntington preferred stock. Cadence series A preferred stock is currently listed on the NYSE under the symbol “CADE-PrA.” The new Huntington depositary shares representing the new Huntington preferred stock are expected to be listed on the NASDAQ upon completion of the merger.

For further information, see the section entitled “The Merger—Treatment of Cadence Series A Preferred Stock” beginning on page 99 and the section entitled “Description of New Huntington Preferred Stock” beginning on page 138.

At the effective time, the portion of each Cadence restricted stock award that was granted in September 2020 with a May 2027 vesting date and that pursuant to its existing terms would vest automatically at the effective time, if any, will (i) fully vest and be cancelled and converted into the right to receive (without interest and less applicable taxes) the merger consideration and (ii) if not covered by clause (i), be assumed and converted based on the exchange ratio into a Huntington restricted stock award with the same terms and conditions as were applicable under such Cadence restricted stock award immediately prior to the effective time (including vesting terms).

At the effective time, each Cadence restricted stock unit award that is outstanding immediately prior to the effective time will (i) if granted to a non-employee member of the Cadence board of directors, fully vest and be converted into the right to receive a number of shares of Huntington common stock based on the exchange ratio, plus an amount in cash equal to the accrued but unpaid dividend equivalent payments applicable to such award and (ii) if not granted to a non-employee member of the Cadence board of directors, be assumed and converted based on the exchange ratio into a Huntington restricted stock unit award (with any performance goals deemed satisfied at the greater of the target and actual level of performance through the latest practicable date prior to the closing (provided that, with respect to any award that is subject to a relative total shareholder return (“rTSR”) modifier and has a performance period ending after December 31, 2025, the rTSR modifier will be determined based on performance measured as of October 21, 2025)) with the same terms and conditions as were applicable under such Cadence restricted stock unit award immediately prior to the effective time (including vesting terms); provided that each such Huntington restricted stock unit award will be subject to service-based vesting only and will no longer be subject to any performance conditions and will be credited with any accrued but unpaid dividend equivalent payments applicable to the underlying Cadence restricted stock unit award.

The merger is intended to qualify as a “reorganization” for U.S. federal income tax purposes, and it is a condition to our respective obligations to complete the merger that Huntington and Cadence each receive a legal opinion to the effect that the merger will so qualify. Accordingly, U.S. holders (as defined in the section entitled “Material U.S. Federal Income Tax Consequences of the Merger”) of Cadence common stock generally will not recognize any gain or loss for U.S. federal income tax purposes on the exchange of their Cadence common stock for Huntington common stock in the merger, except for any gain or loss that may result from the receipt of cash instead of a fractional share of Huntington common stock.

You should be aware that the tax consequences to you of the merger may depend upon your own situation. In addition, you may be subject to state, local or foreign tax laws that are not discussed in this joint proxy statement/prospectus. You should therefore consult with your own tax advisor for a full understanding of the tax consequences to you of the merger.

The Huntington board of directors has determined that the merger, the merger agreement and the transactions contemplated by the merger agreement are advisable and fair to and in the best interests of Huntington and its shareholders and has unanimously adopted and approved the merger agreement, the merger and the other arrangements contemplated by the merger agreement. The Huntington board of directors unanimously recommends that holders of Huntington common stock vote “FOR” the approval of the Huntington share issuance proposal and “FOR” the Huntington adjournment proposal to be presented at the Huntington special meeting. For a more detailed discussion of the Huntington board of directors’ recommendation, see the section entitled “The Merger—Huntington’s Reasons for the Merger; Recommendation of Huntington’s Board of Directors” beginning on page 59.

The Cadence board of directors has unanimously determined that the merger agreement and the transactions contemplated by the merger agreement are advisable and fair to and in the best interests of Cadence and its shareholders and unanimously adopted the merger agreement and approved the merger and the other arrangements contemplated by the merger agreement. The Cadence board of directors unanimously recommends that holders of Cadence common stock vote “FOR” the approval of the merger agreement and “FOR” the other proposals presented at the Cadence special meeting. For a more detailed discussion of the Cadence board of directors’ recommendation, see the section entitled “The Merger—Cadence’s Reasons for the Merger; Recommendation of Cadence’s Board of Directors” beginning on page 61.

Huntington retained Evercore Group L.L.C. (“Evercore”) to act as its financial advisor in connection with the merger. As part of this engagement, the Huntington board of directors requested that Evercore evaluate the fairness, from a financial point of view, to Huntington, of the exchange ratio pursuant to the merger agreement.

At a meeting of the Huntington board of directors held on October 26, 2025, Evercore rendered to the Huntington board of directors its oral opinion, subsequently confirmed by delivery of a written opinion dated October 26, 2025, that as of the date of such opinion and based upon and subject to the assumptions, limitations, qualifications and conditions described in Evercore’s written opinion, the exchange ratio pursuant to the merger was fair, from a financial point of view, to Huntington.

The full text of the written opinion of Evercore, dated October 26, 2025, which sets forth, among other things, the procedures followed, assumptions made, matters considered and qualifications and limitations on the scope of review undertaken in rendering its opinion, is attached as Annex B and is incorporated herein by reference into this joint proxy statement/prospectus in its entirety. The summary of the opinion of Evercore in this proxy statement is qualified in its entirety by reference to the full text of the written opinion. You are urged to read Evercore’s opinion carefully and in its entirety. Evercore’s opinion was addressed to, and provided for the information and benefit of, the Huntington board of directors (solely in its capacity as such) in connection with its evaluation of the proposed merger. The opinion does not constitute a recommendation to the Huntington board of directors or to any other persons in respect of the merger, including as to how any holder of shares of Huntington common stock should vote or act in respect of the merger. Evercore’s opinion does not address the relative merits of the merger as compared to other business or financial strategies that might be available to Huntington, nor does it address the underlying business decision of Huntington to engage in the merger.

For more information, see the section entitled “The Merger—Opinion of Huntington’s Financial Advisor,” beginning on page 65 and the full text of the written opinion of Evercore attached as Annex B to this proxy statement.

In connection with the merger, Cadence’s financial advisor, Keefe, Bruyette & Woods, Inc. (“KBW”), delivered a written opinion, dated October 26, 2025, to Cadence’s board of directors as to the fairness, from a financial point of view and as of the date of KBW’s opinion, to the holders of Cadence common stock of the exchange ratio in the merger. The full text of KBW’s opinion, which describes the procedures followed, assumptions made, matters considered, and qualifications and limitations on the review undertaken by KBW in preparing the opinion, is attached as Annex C to this document. The opinion was for the information of, and was directed to, the Cadence board of directors (in its capacity as such) in connection with its consideration of the financial terms of the merger. The opinion did not address the underlying business decision of Cadence to engage in the merger or enter into the merger agreement or constitute a recommendation to the Cadence board of directors in connection with the merger, and it does not constitute a recommendation to any holder of Cadence common stock or any shareholder of any other entity as to how to vote in connection with the merger or any other matter.

For more information, see the section entitled “The Merger—Opinion of Cadence’s Financial Advisor,” beginning on page 75 and Annex C.

Holders of Huntington common stock are not entitled to appraisal or dissenters’ rights under the MGCL and holders of Cadence common stock are not entitled to appraisal or dissenters’ rights under the MBCA. For more information, see the section entitled “The Merger—Appraisal or Dissenters’ Rights in the Merger” beginning on page 100.

In considering the recommendation of the Cadence board of directors with respect to the merger, Cadence shareholders should be aware that certain of Cadence’s directors and executive officers have interests in the merger, including financial interests, that are different from, or in addition to, the interests of the other shareholders of Cadence generally. The Cadence board of directors was aware of and considered these interests, among other matters, during its deliberations on the merits of the merger and in determining to recommend to Cadence shareholders that they vote for the Cadence merger proposal, the Cadence compensation proposal and the Cadence adjournment proposal.

These interests include, among others, the following:

For a more complete description of these interests, see the section entitled “The Merger—Interests of Cadence’s Directors and Executive Officers in the Merger” beginning on page 91.

At the effective time, the charter of Huntington, as in effect immediately prior to the effective time, will be the charter of Huntington until thereafter amended in accordance with applicable law.

At the effective time, the bylaws of Huntington, as in effect immediately prior to the effective time, will be the bylaws of Huntington until thereafter amended in accordance with applicable law.

Huntington will take all appropriate action so that three (3) current directors of Cadence will be appointed to the Board of Directors of Huntington at the effective time. Each of the directors so appointed will be designated by Huntington, it being agreed that one of the designated directors will be James D. Rollins III, the chairman and chief executive officer of Cadence. In addition, as of the effective time of the merger, Mr. Rollins will be appointed as vice chairman of the boards of directors of each of Huntington and Huntington National Bank. Except for the addition of these three (3) directors and the Vice Chairman appointment, the composition and leadership of the Huntington Board of Directors is not expected to be impacted by the merger.

Following the closing date of the merger, Huntington will maintain the Cadence Bank Foundation and will dedicate any funds in the Cadence Bank Foundation at the effective time to supporting community development and reinvestment and civic and charitable activities within Cadence’s footprint as of the time immediately prior to the effective time of the merger.

Subject to the terms of the merger agreement, Huntington and Cadence have agreed to cooperate with each other and use reasonable best efforts to promptly prepare and file all documentation 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 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 the approval of the Office of the Comptroller of the Currency (“OCC”). The initial filing of the regulatory application to the OCC occurred on November 3, 2025.

Although neither Huntington nor Cadence knows of any reason why it cannot obtain regulatory approval from the OCC in a timely manner, Huntington and Cadence cannot be certain when or if it will be obtained, or that the granting of such regulatory approval will not involve the imposition of conditions on the completion of the merger.

Huntington and Cadence expect the merger to close in the first quarter of 2026. However, neither Huntington nor Cadence can predict the actual date on which the merger will be completed, or if the merger will be completed at all, because completion is subject to conditions and factors outside the control of both companies. Huntington and Cadence must first obtain (i) the approval of holders of Huntington common stock for the issuance of Huntington common stock in connection with the merger and (ii) the approval of holders of Cadence common stock for the merger, as well as obtain necessary regulatory approvals and satisfy certain other closing conditions.

As more fully described in this joint proxy statement/prospectus and in the merger agreement, the completion of the merger depends on a number of conditions being satisfied or, where legally permissible, waived. These conditions include:

The merger agreement may be terminated at any time prior to the completion of the merger, whether before or after the receipt of the requisite Huntington vote or the requisite Cadence vote, in the following circumstances:

If the merger agreement is terminated by either the Huntington Parties or Cadence under certain circumstances, including circumstances involving alternative acquisition proposals and changes in the Huntington board recommendation or the Cadence board recommendation, Cadence or Huntington may be required to pay a termination fee to the other party equal to $296 million.

The merger will be accounted for as an acquisition of Cadence by Huntington under the acquisition method of accounting in accordance with generally accepted accounting principles (“GAAP”).

The rights of holders of Cadence common stock are governed by Mississippi law and by the articles of incorporation and bylaws of Cadence. In the merger, holders of Cadence common stock will become holders of Huntington common stock, and their rights will be governed by Maryland law and the charter of Huntington and the bylaws of Huntington. Holders of Cadence common stock will have different rights once they become holders of Huntington common stock due to differences between the Cadence governing documents and Mississippi law, on the one hand, and the Huntington governing documents and Maryland law, on the other hand. These differences are described in more detail under the section entitled “Comparison of Shareholders’ Rights” beginning on page 145.

The shares of Huntington common stock are, and new Huntington depositary shares representing one one-thousandth (1/1000th) of a share of new Huntington preferred stock to be issued in the merger are expected to be, listed for trading on the NASDAQ. Following the merger, shares of Huntington common stock will continue to be listed on the NASDAQ. In addition, following the merger, Cadence common stock and Cadence series A preferred stock will be delisted from the NYSE and deregistered under the Exchange Act.

The Huntington special meeting will be held virtually on [   ], 2025 at [   ], at [   ], Eastern Time. At the Huntington special meeting, holders of Huntington common stock will be asked to consider and vote on the following matters:

You may vote at the Huntington special meeting if you owned shares of Huntington common stock at the close of business on [   ], 2025. On that date, there were [   ] shares of Huntington common stock outstanding, approximately [   ] percent ([   ]%) of which were owned and entitled to be voted by Huntington directors and executive officers and their affiliates. We currently expect that Huntington’s directors and executive officers will vote their shares in favor of the Huntington share issuance proposal and the Huntington adjournment proposal to be considered at the Huntington special meeting, although none of them has entered into any agreements obligating them to do so.

The Huntington share issuance proposal will be approved if a majority of the votes cast by holders of Huntington common stock at the Huntington special meeting are voted in favor of such proposal. The Huntington adjournment proposal will be approved if a majority of the votes cast on the Huntington adjournment proposal by the holders of Huntington common stock entitled to vote are voted in favor of such proposal. If you mark “ABSTAIN” on your proxy, fail to submit a proxy or vote at the Huntington special meeting via the Huntington special meeting website or fail to instruct your bank, broker, trustee or other nominee how to vote with respect to the Huntington share issuance proposal, you will not be deemed to have cast a vote with respect to the Huntington share issuance proposal and it will have no effect on the Huntington share issuance proposal. If you mark “ABSTAIN” on your proxy, fail to submit a proxy or vote at the Huntington special meeting via the Huntington special meeting website or fail to instruct your bank, broker, trustee or other nominee how to vote with respect to the Huntington adjournment proposal, you will not be deemed to have cast a vote with respect to the Huntington adjournment proposal and it will have no effect on the Huntington adjournment proposal.

The Cadence special meeting will be held virtually on [   ], 2025 at [   ], at [   ], Central Time. At the Cadence special meeting, holders of Cadence common stock will be asked to consider and vote on the following matters:

You may vote at the Cadence special meeting if you owned shares of Cadence common stock at the close of business at the close of business on [  ], 2025. On that date, there were [  ] shares of Cadence common stock outstanding, approximately [  ] percent ([  ]%) of which were owned and entitled to be voted by Cadence directors and executive officers and their affiliates. Cadence currently expects that Cadence’s directors and executive officers will vote their shares in favor of the merger and the other proposals to be considered at the Cadence special meeting, although none of them has entered into any agreements obligating them to do so.

The Cadence merger proposal will be approved if the holders of a majority of the outstanding shares of Cadence common stock entitled to vote at the Cadence special meeting vote in favor of such proposal. Each of the Cadence compensation proposal and the Cadence adjournment proposal will be approved if a majority of the votes cast by the holders of Cadence common stock entitled to vote on such proposal are voted in favor of such proposal. If you mark “ABSTAIN” on your proxy, fail to submit a proxy or vote at the Cadence special meeting via the Cadence special meeting website or fail to instruct your bank, broker, trustee or other nominee how to vote with respect to the Cadence merger proposal, it will have the same effect as a vote “AGAINST” the Cadence merger proposal. If you mark “ABSTAIN” on your proxy, fail to submit a proxy or vote at the Cadence special meeting via the Cadence special meeting website or fail to instruct your bank, broker, trustee or other nominee how to vote with respect to the Cadence compensation proposal or the Cadence adjournment proposal, you will not be deemed to have cast a vote with respect to Cadence compensation proposal or the Cadence adjournment proposal and it will have no effect on such proposals.

In evaluating the merger agreement and the merger, including the issuance of shares of Huntington common stock in the merger, you should carefully read this joint proxy statement/prospectus and give special consideration to the factors discussed in the section entitled “Risk Factors” beginning on page 34.