X0609 4 2026-05-14 0 0001748824 Acadian Asset Management Inc. AAMI 0001668247 Chersi Robert J false C/O ACADIAN ASSET MANAGEMENT INC. 200 STATE STREET, SUITE 601A BOSTON MA 02109 1 0 0 0 0 Common Stock 2026-05-14 4 M 0 3286 0 A 3286 D Common Stock 37384 I By Robert J. Chersi 2012 Family Trust Restricted Stock Units 2026-05-14 4 M 0 3286 0 D Common Stock 3286 0 D These shares are held in trust for the benefit of the reporting person's children. The reporting person's spouse is the trustee of the trust. Each restricted stock unit represents a right to receive one share of common stock of Acadian Asset Management Inc. On May 14, 2025, the reporting person was granted 3,286 restricted stock units vesting upon the earlier of May 14, 2026 and the date of the 2026 annual meeting of stockholders of Acadian Asset Management Inc. /s/ Richard J. Hart, By POA for Robert J. Chersi 2026-05-18