As filed with the Securities and Exchange Commission on November 24, 2025

Registration No. 333-291742

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

Farmers National Banc Corp.

(Exact name of registrant as specified in its charter)

Ohio	6022	34-1371693
(State or other jurisdiction of incorporation or organization)	(Primary Standard Industrial Classification Code Number)	(I.R.S. Employer Identification No.)

20 South Broad Street Canfield Ohio 44406 (330) 533-3341 (Address, including zip code, and telephone number, including area code of registrant’s principal executive offices) Kevin J. Helmick President and Chief Executive Officer Farmers National Banc Corp. 20 South Broad Street Canfield, Ohio 44406 (330) 533-3341 (Name, address, including zip code, and telephone number, including area code, of agent for service)

With Copies to:

J. Bret Treier, Esq. Vorys, Sater, Seymour and Pease LLP 50 S. Main Street Suite 1200 Akron, Ohio 44308 (330) 208-1015 J. Brennan Ryan, Esq. Nelson Mullins Riley & Scarborough LLP 201 17th Street NW, Suite 1700 Atlanta, Georgia 30363 (404) 322-6000

Approximate date of commencement of the proposed sale of the securities to the public: As soon as practicable after this registration statement becomes effective and upon completion of the merger of Middlefield Banc Corp. with and into Farmers National Banc Corp.

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

Large accelerated filer	☐	Accelerated filer	☒
Non-accelerated filer	☐	Smaller reporting company	☐
		Emerging growth company	☐

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

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

Exchange Act Rule 13e-4(i) (Cross-Border Issuer Tender Offer)	☐
Exchange Act Rule 14d-1(d) (Cross-Border Third-Party Tender Offer)	☐

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

EXPLANATORY NOTE

Farmers National Banc Corp. is filing this Amendment No. 1 to the Registration Statement on Form S-4 (Registration No. 333- 291742) (the “Registration Statement”) solely for the purpose of including a conformed signature on Exhibit 23.3, the S. R. Snodgrass, P.C. consent. Exhibit 23.3 to the Registration Statement was manually signed prior to filing, however, the conformed signature was inadvertently omitted. Other than including a conformed signature, no other modifications have been made to the Registration Statement.

PART II

INFORMATION NOT REQUIRED IN THE PROSPECTUS

Item 20. Indemnification of Directors and Officers.

(a) Ohio General Corporation Law

Section 1701.13(E) of the Ohio Revised Code grants corporations broad powers to indemnify directors, officers, employees and agents. Section 1701.13(E) provides:

(E)(1) corporation may indemnify or agree to indemnify any person who was or is a party, or is threatened to be made a party, to any threatened, pending, or completed action, suit, or proceeding, whether civil, criminal, administrative, or investigative, other than an action by or in the right of the corporation, by reason of the fact that the person is or was a director, officer, employee, or agent of the corporation, or is or was serving at the request of the corporation as a director, trustee, officer, employee, member, manager, or agent of another corporation, domestic or foreign, nonprofit or for profit, a limited liability company, or a partnership, joint venture, trust, or other enterprise, against expenses, including attorney’s fees, judgments, fines, and amounts paid in settlement actually and reasonably incurred by the person in connection with such action, suit, or proceeding, if the person acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, if the person had no reasonable cause to believe the person’s conduct was unlawful. The termination of any action, suit, or proceeding by judgment, order, settlement, or conviction, or upon a plea of nolo contendere or its equivalent, shall not, of itself, create a presumption that the person did not act in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding, the person had reasonable cause to believe that the person’s conduct was unlawful.

(2) A corporation may indemnify or agree to indemnify any person who was or is a party, or is threatened to be made a party, to any threatened, pending, or completed action or suit by or in the right of the corporation to procure a judgment in its favor, by reason of the fact that the person is or was a director, officer, employee, or agent of the corporation, or is or was serving at the request of the corporation as a director, trustee, officer, employee, member, manager, or agent of another corporation, domestic or foreign, nonprofit or for profit, a limited liability company, or a partnership, joint venture, trust, or other enterprise, against expenses, including attorney’s fees, actually and reasonably incurred by the person in connection with the defense or settlement of such action or suit, if the person acted in good faith and in a manner the person reasonably believed to be in or not opposed to the best interests of the corporation, except that no indemnification shall be made in respect of any of the following:

(a) Any claim, issue, or matter as to which such person is adjudged to be liable for negligence or misconduct in the performance of the person’s duty to the corporation unless, and only to the extent that, the court of common pleas or the court in which such action or suit was brought determines, upon application, that, despite the adjudication of liability, but in view of all the circumstances of the case, such person is fairly and reasonably entitled to indemnity for such expenses as the court of common pleas or such other court shall deem proper;

(b) Any action or suit in which the only liability asserted against a director is pursuant to section 1701.95 of the Revised Code.

(3) To the extent that a director, trustee, officer, employee, member, manager, or agent has been successful on the merits or otherwise in defense of any action, suit, or proceeding referred to in division (E)(1) or (2) of this section, or in defense of any claim, issue, or matter in the action, suit, or proceeding, the person shall be indemnified against expenses, including attorney’s fees, actually and reasonably incurred by the person in connection with the action, suit, or proceeding.

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(4) Any indemnification under division (E)(1) or (2) of this section, unless ordered by a court, shall be made by the corporation only as authorized in the specific case, upon a determination that indemnification of the director, trustee, officer, employee, member, manager, or agent is proper in the circumstances because the person has met the applicable standard of conduct set forth in division (E)(1) or (2) of this section. Such determination shall be made as follows:

(a) By a majority vote of a quorum consisting of directors of the indemnifying corporation who were not and are not parties to or threatened with the action, suit, or proceeding referred to in division (E)(1) or (2) of this section;

(b) If the quorum described in division (E)(4)(a) of this section is not obtainable or if a majority vote of a quorum of disinterested directors so directs, in a written opinion by independent legal counsel other than an attorney, or a firm having associated with it an attorney, who has been retained by or who has performed services for the corporation or any person to be indemnified within the past five years;

(c) By the shareholders;

(d) By the court of common pleas or the court in which the action, suit, or proceeding referred to in division (E)(1) or (2) of this section was brought.

Any determination made by the disinterested directors under division (E)(4)(a) or by independent legal counsel under division (E)(4)(b) of this section shall be promptly communicated to the person who threatened or brought the action or suit by or in the right of the corporation under division (E)(2) of this section, and, within ten days after receipt of that notification, the person shall have the right to petition the court of common pleas or the court in which the action or suit was brought to review the reasonableness of that determination.

(5)(a) Unless at the time of a director’s act or omission that is the subject of an action, suit, or proceeding referred to in division (E)(1) or (2) of this section, the articles or the regulations of a corporation state, by specific reference to this division, that the provisions of this division do not apply to the corporation and unless the only liability asserted against a director in an action, suit, or proceeding referred to in division (E)(1) or (2) of this section is pursuant to section 1701.95 of the Revised Code, expenses, including attorney’s fees, incurred by a director in defending the action, suit, or proceeding shall be paid by the corporation as they are incurred, in advance of the final disposition of the action, suit, or proceeding, upon receipt of an undertaking by or on behalf of the director in which the director agrees to do both of the following:

(i) Repay that amount if it is proved by clear and convincing evidence in a court of competent jurisdiction that the director’s action or failure to act involved an act or omission undertaken with deliberate intent to cause injury to the corporation or undertaken with reckless disregard for the best interests of the corporation;

(ii) Reasonably cooperate with the corporation concerning the action, suit, or proceeding.

(b) Expenses, including attorney’s fees, incurred by a director, trustee, officer, employee, member, manager, or agent in defending any action, suit, or proceeding referred to in division (E)(1) or (2) of this section, may be paid by the corporation as they are incurred, in advance of the final disposition of the action, suit, or proceeding, as authorized by the directors in the specific case, upon receipt of an undertaking by or on behalf of the director, trustee, officer, employee, member, manager, or agent to repay that amount, if it ultimately is determined that the person is not entitled to be indemnified by the corporation.

(6) The indemnification or advancement of expenses authorized by this section shall not be exclusive of, and shall be in addition to, any other rights granted to those seeking indemnification or advancement of expenses under the articles, the regulations, any agreement, a vote of shareholders or disinterested directors, or otherwise, both as to action in their official capacities and as to action in another capacity while holding their offices or

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positions, and shall continue as to a person who has ceased to be a director, trustee, officer, employee, member, manager, or agent and shall inure to the benefit of the heirs, executors, and administrators of that person. A right to indemnification or to advancement of expenses arising under a provision of the articles or the regulations shall not be eliminated or impaired by an amendment to that provision after the occurrence of the act or omission that becomes the subject of the civil, criminal, administrative, or investigative action, suit, or proceeding for which the indemnification or advancement of expenses is sought, unless the provision in effect at the time of that act or omission explicitly authorizes that elimination or impairment after the act or omission has occurred.

(7) A corporation may purchase and maintain insurance or furnish similar protection, including, but not limited to, trust funds, letters of credit, or self-insurance, on behalf of or for any person who is or was a director, officer, employee, or agent of the corporation, or is or was serving at the request of the corporation as a director, trustee, officer, employee, member, manager, or agent of another corporation, domestic or foreign, nonprofit or for profit, a limited liability company, or a partnership, joint venture, trust, or other enterprise, against any liability asserted against the person and incurred by the person in any such capacity, or arising out of the person’s status as such, whether or not the corporation would have the power to indemnify the person against that liability under this section. Insurance may be purchased from or maintained with a person in which the corporation has a financial interest.

(8) The authority of a corporation to indemnify persons pursuant to division (E)(1) or (2) of this section does not limit the payment of expenses as they are incurred, indemnification, insurance, or other protection that may be provided pursuant to divisions (E)(5), (6), and (7) of this section. Divisions (E)(1) and (2) of this section do not create any obligation to repay or return payments made by the corporation pursuant to division (E)(5), (6), or (7).

(9) As used in division (E) of this section, “corporation” includes all constituent entities in a consolidation or merger and the new or surviving corporation, so that any person who is or was a director, officer, employee, trustee, member, manager, or agent of such a constituent entity, or is or was serving at the request of such constituent entity as a director, trustee, officer, employee, member, manager, or agent of another corporation, domestic or foreign, nonprofit or for profit, a limited liability company, or a partnership, joint venture, trust, or other enterprise, shall stand in the same position under this section with respect to the new or surviving corporation as the person would if the person had served the new or surviving corporation in the same capacity.

(b) Articles of Incorporation, as amended, of Farmers National Banc Corp.

Article X of the Articles of Incorporation, as amended, provides for the indemnification of Farmers officers and directors as follows:

The corporation shall have power to, and may (in addition to such other power conferred by law) indemnify any shareholder, officer, or director of the corporation who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, administrative, or investigative, by reason of the fact that he is or was a director of this corporation, or any corporation (hereinafter referred to as “subsidiary corporation”) of which more than 50 per cent of the issued and outstanding shares of common shares was or is owned by the corporation at the time such person was or is serving as such director of the “subsidiary corporation,” against expenses (including those reasonably incurred by him) in connection with such action, suit, and proceeding if the principal issue of such action, suit, or proceeding involved or involves a contract or transaction by and between the corporation and such “subsidiary corporation” and if he acted in good faith and in a manner he reasonably believed to be in or not opposed to the best interests of the “subsidiary corporation.” Any indemnification as above provided (unless ordered by a court) shall be made by the corporation only as authorized in the specific case upon a determination that indemnification is proper in the circumstances because the standard of conduct set forth above has been met. Such determination shall be made (a) by the Board of Directors by a majority vote of a quorum consisting of directors who were not parties to such action, suit or proceeding; (b) if such a quorum is not obtainable, or even if obtainable, if a majority vote of a quorum of

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disinterested directors so directs, by independent legal counsel in a written opinion; or (c) by a majority of a quorum of the shareholders of the corporation consisting of shareholders who were not parties to such action, suit or proceeding.

(c) Indemnification Agreements

Farmers presently maintains indemnification agreements with each of its directors and key officers, and maintains insurance for the benefit of persons entitled to indemnification.

Item 21. Exhibits and Financial Statement Schedules.

(a) The following exhibits are filed herewith or incorporated herein by reference as part of this Registration Statement:

Exhibit Number	Description
2.1	Agreement and Plan of Merger by and between Farmers National Banc Corp. and Middlefield Banc Corp., dated as of October  22, 2025 (included as Annex A to the proxy statement/prospectus forming a part of this Registration Statement).†**
3.1	Articles of Incorporation of Farmers National Banc Corp., as amended (incorporated by reference from Exhibit 4.1 to Farmers’ Registration Statement on Form S-3 filed with the SEC on October 3, 2001).
3.2	Amendment to Articles of Incorporation of Farmers National Banc Corp., as amended (incorporated by reference from Exhibit 3.1 to Farmers’ Current Report on Form 8-K filed with the SEC on May 1, 2013).
3.3	Amendment to Articles of Incorporation of Farmers National Banc Corp., as amended (incorporated by reference from Exhibit 3.1 to Farmers’ Current Report on Form 8-K filed with the SEC on April 20, 2018).
3.4	Amended Code of Regulations of Farmers National Banc Corp. (incorporated by reference from Exhibit  3.1 to Farmers’ Current Report on Form 8-K filed with the SEC on April 17, 2020).
4.1	Description of Capital Stock. (incorporated by reference from Exhibit 4.1 to Farmers’ Annual Report on Form 10-K for year ended December 31, 2023 filed with the Commission on March 7, 2024).
4.2	Form of 3.125% Fixed to Floating Rate Subordinated Note Due 2031 (incorporated by reference from Exhibit 10.1 to Farmers’ Current Report on Form 8-K filed with the SEC on November 17, 2021).
5.1	Opinion of Vorys, Sater, Seymour and Pease LLP as to the legality of the securities being registered.**
8.1	Opinion of Vorys, Sater, Seymour and Pease LLP regarding certain tax matters.*
8.2	Opinion of Nelson Mullins Riley & Scarborough LLP regarding certain tax matters.*
21	Subsidiaries of Farmers National Banc Corp. (incorporated by reference from Exhibit 21 to Farmers’ Annual Report on Form 10-K filed with the SEC on February 26, 2025).
23.1	Consent of Crowe LLP, regarding Farmers National Banc Corp.**
23.2	Consent of CliftonLarsonAllen LLP, regarding Farmers National Banc Corp.**
23.3	Consent of S.R. Snodgrass, P.C., regarding Middlefield Banc Corp. (filed herewith)
23.4	Consent of Vorys, Sater, Seymour and Pease LLP (included as part of its opinion filed as Exhibit 5.1).**
23.5	Consent of Vorys, Sater, Seymour and Pease LLP (included as part of its opinion filed as Exhibit 8.1).*

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Exhibit Number	Description
23.6	Consent of Nelson Mullins Riley & Scarborough LLP (included as part of its opinion filed as Exhibit 8.2).*
24.1	Power of Attorney**
99.1	Form of Proxy for Special Meeting of Farmers National Banc Corp. Shareholders*
99.2	Form of Proxy for Special Meeting of Middlefield Banc Corp. Shareholders*
99.3	Consent of Janney & Associates, Inc.**
99.4	Consent of Raymond James  & Associates, Inc. (included as Annex C to the proxy statement/prospectus forming a part of this Registration Statement).**
107	Filing Fee Table**

† Pursuant to Item 601(a)(5) of Regulation S-K, certain schedules and similar attachments have been omitted. The registrant hereby agrees to furnish a copy of any omitted schedule or similar attachment to the SEC upon request.

* To be filed by amendment.

** Previously filed.

Item 22. Undertakings.

(a) The undersigned registrant hereby undertakes:

(1) To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

i. to include any prospectus required by Section 10(a)(3) of the Securities Act of 1933;

ii. to reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in the volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than a 20% change in the maximum aggregate offering price set forth in the “Calculation of Registration Fee” table in the effective registration statement;

iii. to include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement.

(2) That, for the purpose of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(3) To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

(b) (1) The undersigned registrant hereby undertakes as follows: that prior to any public reoffering of the securities registered hereunder through use of a prospectus which is a part of this registration statement, by any

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person or party who is deemed to be an underwriter within the meaning of Rule 145(c), the issuer undertakes that such reoffering prospectus will contain the information called for by the applicable registration form with respect to reofferings by persons who may be deemed underwriters, in addition to the information called for by the other items of the applicable form.

(2) The registrant undertakes that every prospectus (i) that is filed pursuant to paragraph (1) immediately preceding or (ii) that purports to meet the requirements of section 10(a)(3) of the Act and is used in connection with an offering of securities subject to Rule 415, will be filed as a part of an amendment to the registration statement and will not be used until such amendment is effective, and that, for purposes of determining any liability under the Securities Act of 1933, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(c) Insofar as indemnification for liabilities arising under the Securities Act of 1933 may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

(d) That, for the purpose of determining liability of the registrant under the Securities Act of 1933 to any purchaser in the initial distribution of securities, in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser: (i) any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424; (ii) any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant; (iii) the portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and (iv) any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

(e) The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act of 1933, each filing of the registrant’s annual report pursuant to Section 13(a) or Section 15(d) of the Securities Exchange Act of 1934 (and, where applicable, each filing of an employee benefit plan’s annual report pursuant to Section 15(d) of the Securities Exchange Act of 1934) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

(f) The undersigned registrant hereby undertakes to respond to requests for information that is incorporated by reference into the prospectus pursuant to Items 4, 10(b), 11, or 13 of this Form, within one business day of receipt of such request, and to send the incorporated documents by first class mail or other equally prompt means. This includes information contained in documents filed subsequent to the effective date of the registration statement through the date of responding to the request.

(g) The undersigned registrant hereby undertakes to supply by means of a post-effective amendment all information concerning a transaction, and the company being acquired involved therein, that was not the subject of and included in the registration statement when it became effective.

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SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, the Registrant has duly caused this Registration Statement on Form S-4 to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Canfield, State of Ohio, on November 24, 2025.

FARMERS NATIONAL BANC CORP.
By:	/s/ Kevin J. Helmick
	Kevin J. Helmick, President and Chief Executive Officer

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement on Form S-4 has been signed by the following persons in the capacities indicated on November 24, 2025.

Signature	Title
/s/ Kevin J. Helmick Kevin J. Helmick	President, Chief Executive Officer and Director (Principal Executive Officer)
/s/ Troy Adair Troy Adair	Executive Vice President, Secretary and Chief Financial Officer (Principal Financial Officer)
/s/ Sherry Commons Sherry Commons	Chief Accounting Officer (Principal Accounting Officer)
/s/ Gregory C. Bestic* Gregory C. Bestic	Director
/s/ Carl D. Culp * Carl D. Culp	Director
/s/ Neil J. Kaback* Neil J. Kaback	Director
/s/ Frank J. Monaco* Frank J. Monaco	Director
/s/ Terry A. Moore * Terry A. Moore	Director, Chairman of the Board
/s/ Edward W. Muransky* Edward W. Muransky	Director
/s/ David Z. Paull * David Z. Paull	Director
/s/ Gina A. Richardson * Gina A. Richardson	Director
/s/ André Thornton * André Thornton	Director

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Signature	Title
/s/ Nicholas D. Varischetti* Nicholas D. Varischetti	Director

* The undersigned, by signing his name hereto, does hereby sign this Registration Statement on Form S-4 on behalf of each of the directors of the Registrant identified above pursuant to a Power of Attorney executed by the directors identified above, which Power of Attorney has been filed with this Registration Statement on Form S-4 as Exhibit 24.1.

/s/ Kevin J. Helmick	Date: November 24, 2025
Kevin J. Helmick Attorney-in-Fact

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