Post-effective Amendment to Registration Statement for Employee Benefit Plan (Form S-8 POS)

File No. 333-269316

File No. 333-269317

File No. 333-279996

As filed with the Securities and Exchange Commission on October 1, 2026

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

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POST-EFFECTIVE AMENDMENT NO. 1

TO

FORM S-8

REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

First Seacoast Bancorp, Inc.

(Exact Name of Registrant as Specified in its Charter)

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

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

This Registration Statement shall become effective upon filing in accordance with Rule 464 promulgated under the Securities Act of 1933, as amended.

EXPLANATORY NOTE

This Post-Effective Amendment No. 1 relates to each of the following Registration Statements on Form S-8 (each, a "Registration Statement" and collectively, the "Registration Statements") filed with the Securities and Exchange Commission (the "SEC") by First Seacoast Bancorp, Inc. (the "Registrant"):

In connection with the consummation of the merger of the Registrant with and into Cambridge Financial Group, Inc., through a series of integrated transactions, with Cambridge Financial Group, Inc. as the surviving corporation, effective October 1, 2026, the Registrant intends to terminate and suspend all reporting obligations with the SEC under the Securities Exchange Act of 1934, as amended. Accordingly, pursuant to the undertaking contained in the Registration Statements to remove from registration by means of a post-effective amendment any of the securities that remain unsold at the termination of the offering, the Registrant hereby amends the Registration Statements by deregistering all shares of the Registrant's common stock, and all options therefor, that remain unissued and unsold under the Registration Statements, if any, as of the date hereof.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all the requirements for filing on Form S-8 and has duly caused this Post-Effective Amendment No. 1 to the Registration Statements on Form S-8 to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Dover, New Hampshire, on October 1, 2026.

Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed by the following persons in the capacities and on the date indicated.

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