Prospectus by Investment Company (Form 497)

MSS Series Trust

One Rock Fund

Ticker: ONERX

SUPPLEMENT DATED JUNE 16, 2026 TO THE STATEMENT OF ADDITIONAL INFORMATION ("SAI") DATED MARCH 31, 2026

Effective May 12, 2026, (i) Brandon M. Pokersnik resigned as Treasurer, Secretary and Chief Compliance Officer of the Trust; (ii) Empirical Administration, LLC concluded providing administration and compliance services to the Trust; (iii) the Board appointed Bob Anastasi as Treasurer, Secretary and Chief Compliance Officer of the Trust; and (iv) the Board approved Hanover Fund Administration, LLC to provide administrator and compliance services to the Trust. Any information in the SAI to the contrary should be disregarded.

Accordingly, the Interested Trustee and Officer table under the section entitled "Trustee Qualifications" is replaced with the following:

Interested Trustee and Officer

¹ Gregory B. Getts is considered an "Interested" Trustee as defined in the 1940 Act because he is an officer of the Trust and President/owner of the Fund's distributor.

² The "Fund Complex" consists of MSS Series Trust.

Furthermore, the section entitled "Administrator and Compliance Services" is replaced with the following:

Effective May 12, 2026, Hanover Fund Administration, LLC ("Hanover"), 8000 Town Centre Drive, Suite 400, Broadview Heights, Ohio, 44147, will serve as the Fund's administrator and provide compliance services to the Fund. Hanover will be paid $500 per month for its administration services and $250 per month for its compliance services. Bob Anastasi of Hanover is also the CCO of the Trust.

From December 1, 2019, to May 12, 2026, Empirical Administration, LLC ("Empirical"), 8000 Town Centre Drive, Suite 400, Broadview Heights, Ohio, 44147, provided administration and compliance services to the Trust. Empirical was paid $750 per month for its services provided under the Administration and Compliance Agreement.

During the fiscal year ended November 30, 2023, the Fund paid Empirical $6,000 for compliance services and $3,000 for administrative services. During the fiscal year ended November 30, 2024, the Fund paid Empirical $5,932 for compliance services and $2,968 for administrative services. During the fiscal year ended November 30, 2025, the Fund paid Empirical $6,000 for compliance services and $2,967 for administrative services.

You should read this Supplement in conjunction with the Fund's Statement of Additional Information, dated March 31, 2026. These documents are available upon request and without charge by calling the Fund at 1-800-564-3899 or by writing to the Fund at 8000 Town Centre Drive, Suite 400, Broadview Heights, Ohio 44147-4031.

Please retain this Supplement for future reference.