Filed pursuant to Rule 

APOLLO S3 PRIVATE MARKETS FUND (THE “FUND”)

SUPPLEMENT DATED FEBRUARY 12, 2026 TO THE

PROSPECTUS DATED AUGUST 1, 2025, AS AMENDED NOVEMBER 5, 2025

This prospectus supplement (this “Supplement”) is part of and should be read in conjunction with each applicable Prospectus (each, a “Prospectus”) and the Statement of Additional Information (the “SAI”) for Class I, Class S2 and Class I2 Shares of Apollo S3 Private Markets Fund, each dated August 1, 2025, as amended November 5, 2025. Unless otherwise indicated, all other information included in a Prospectus or the SAI that is not inconsistent with the information set forth in this Supplement remains unchanged. Unless otherwise defined herein, capitalized terms used in this Supplement shall have the same meaning as in each Prospectus and/or SAI, as applicable. References herein to the “Fund,” “we,” “us,” or “our” refer to Apollo S3 Markets Fund and its subsidiaries unless the context specifically requires otherwise.

Effective immediately, the following changes are made to each Prospectus and the SAI:

The business operations of the Fund are managed and supervised under the direction of the Fund’s Board of Trustees (the “Board” and each member of the Board, a “Trustee”), subject to the laws of the State of Delaware and the Fund’s Declaration of Trust. The Board is comprised of six Trustees, a majority of whom are not “interested persons” (as defined in the 1940 Act) of the Fund (“Independent Trustees”). The Board has overall responsibility for the management and supervision of the business operations of the Fund.

A majority of the Fund’s Trustees are Independent Trustees and are not affiliated with the Adviser. The Board currently has two standing committees: an audit committee (the “Audit Committee”) and a governance committee (the “Governance Committee”).

The Audit Committee operates pursuant to a charter approved by the Board. The charter sets forth the responsibilities of the Audit Committee. The primary function of the Audit Committee is to serve as an independent and objective party to assist the Board in selecting, engaging and discharging the independent accountants, reviewing the plans, scope and results of the audit engagement with the Fund’s independent accountants, approving professional services provided by the independent accountants (including compensation therefore), reviewing the independence of the independent accountants and reviewing the adequacy of the internal controls over financial reporting. The Audit Committee is presently composed of five persons, including Meredith Coffey, Christine Gallagher, Michael Porter, Carl J. Rickertsen and Sheryl Schwartz, all of whom are considered independent for purposes of the 1940 Act. Carl J. Rickertsen serves as the chair of the Audit Committee. The Board has determined that Sheryl Schwartz and Carl J. Rickertsen each qualify as an “audit committee financial expert” as defined in Item 3 of Form under the 1940 Act. Each of the members of the Audit Committee is not an “interested person” of the Fund or of the Adviser as defined in Section 2(a)(19) of the 1940 Act.

A copy of the charter of the Audit Committee is available in print to any Shareholder who requests it.

The Governance Committee operates pursuant to a charter approved by the Board. The charter sets forth the responsibilities of the Governance Committee, including making nominations for the appointment or election of Independent Trustees, subject to the oversight of the Board. The Governance Committee consists of five persons, including Meredith Coffey, Christine Gallagher, Michael Porter, Carl J. Rickertsen and Sheryl Schwartz, all of whom are considered independent for purposes of the 1940 Act. Meredith Coffey serves as the chair of the Governance Committee. The Fund does not hold annual shareholder meetings. As such, the Governance Committee will not typically consider nominees recommended by security holders.

A copy of charter of the Governance Committee is available in print to any Shareholder who requests it.

 

Ms. Schwartz is a Trustee, a member of the Fund’s Audit Committee and a member of the Fund’s Governance Committee. Ms. Schwartz served as Chief Investment Officer of Alti Financial, a platform focused on democratizing private equity, from November 2021 until 2025. From 2013 to 2020, she was a Managing Director at Caspian Private Equity, where she managed an investment portfolio of private market investments of more than $3 billion. From 2010 to 2013, she was a Senior Managing Director at Perseus and Managing Director of Perseus Mezzanine Finance. From 1988 to 2010, Ms. Schwartz served as Managing Director of Alternative Investments at TIAA, a Fortune 100 diversified financial services firm, managing an investment portfolio of more than $13 billion. Ms. Schwartz is also a board member of Cartesian Growth II since 2021 and GAIA Reit since 2023 and other Apollo fund boards. In addition to her commercial activities, Ms. Schwartz also is an Adjunct Professor of Private Equity and Finance at the Fordham Gabelli School of Business, and a board member of the Women’s Association of Venture and Equity (WAVE) 2007. Ms. Schwartz received both her master’s in business administration and bachelor’s degree from New York University.