and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended. Such information shall not be incorporated by reference into any filing under the Securities Act of 1933, as amended, except as may be expressly set forth in a specific filing. Exhibit No. Description 99.1 Second quarter 2026 earnings presentation of Acadian Asset Management Inc. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document) SIGNATURE Pursuant…

Annual board election with no significant changes in management.

and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended. Such information shall not be incorporated by reference into any filing under the Securities Act of 1933, as amended, except as may be expressly set forth in a specific filing. Exhibit No. Description 99.1 First quarter 2026 earnings presentation of Acadian Asset Management Inc. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document) SIGNATURE Pursuant t…

and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended. Such information shall not be incorporated by reference into any filing under the Securities Act of 1933, as amended, except as may be expressly set forth in a specific filing. Exhibit No. Description 99.1 Fourth quarter 2025 earnings presentation of Acadian Asset Management Inc. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document) SIGNATURE Pursuant…

Other Events. As previously disclosed, on October 30, 2025, Acadian Asset Management Inc. (the “Company”) issued a notice for the full redemption of all $275 million aggregate principal amount outstanding of its 4.800% Senior Notes due July 27, 2026 (CUSIP: 10948WAA1) (the “2026 Notes”). The 2026 Notes were issued under (i) the Indenture, dated as of July 25, 2016, among the Company, Wilmington Trust, National Association, as Trustee (the “Trustee”), and Citibank, N.A., as Securities Administ…

and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended. Such information shall not be incorporated by reference into any filing under the Securities Act of 1933, as amended, except as may be expressly set forth in a specific filing. Exhibit No. Description 10.1 Delayed Draw Term Loan Credit Agreement, dated as of October 28, 2025, among Acadian Asset Management LLC, the Lenders from time to time party thereto, and Bank of America, N…

Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant. The information set forth in

Entry into a Material Definitive Agreement. On October 28, 2025 (the "Closing Date"), Acadian Asset Management LLC (“Acadian LLC”), a majority owned subsidiary of Acadian Asset Management Inc. (the “Company”), entered into a Delayed Draw Term Loan Credit Agreement and a Revolving Credit Agreement, in each case as defined and described under the applicable subheadings below. Delayed Draw Term Loan Credit Agreement On the Closing Date, Acadian LLC entered into a Delayed Draw Term Loan Credit Ag…

hereto. Loans under the DDTL Credit Agreement bear interest, at Acadian LLC’s option, at a rate per annum equal to (i) Term SOFR (as defined in the DDTL Credit Agreement) for the applicable interest period plus an applicable margin equal to a range of 1.50% to 2.00% depending on Acadian LLC’s consolidated leverage ratio or (ii) an alternate base rate (defined as a rate equal to the highest of (i) the Federal Funds Rate plus 1/2 of 1%, (ii) Bank of America's published "prime rate" and (iii) Te…

and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended. Such information shall not be incorporated by reference into any filing under the Securities Act of 1933, as amended, except as may be expressly set forth in a specific filing. Exhibit No. Description 99.1 Second quarter 2025 earnings presentation of Acadian Asset Management Inc. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document) SIGNATURE Pursuant…

CFO — Scott Hynes: The filing announces the appointment of an external candidate, Scott Hynes, as the new Chief Financial Officer, which is a significant management change but not a departure of an existing executive.

and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended. Such information shall not be incorporated by reference into any filing under the Securities Act of 1933, as amended, except as may be expressly set forth in a specific filing. Exhibit No. Description 99.1 First quarter 2025 earnings presentation of Acadian Asset Management Inc. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document) SIGNATURE Pursuant t…

and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended. Such information shall not be incorporated by reference into any filing under the Securities Act of 1933, as amended, except as may be expressly set forth in a specific filing. Exhibit No. Description 99.1 Fourth quarter 2024 earnings presentation of Acadian Asset Management Inc. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document) SIGNATURE Pursuant…

and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended. Such information shall not be incorporated by reference into any filing under the Securities Act of 1933, as amended, except as may be expressly set forth in a specific filing. Exhibit No. Description 99.1 Third quarter 2024 earnings presentation of BrightSphere Investment Group Inc. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document) SIGNATURE Pursu…

CEO — Kelly Young: The filing announces the appointment of an external candidate, Kelly Young, as President and CEO, which is a significant management change but not a departure of a sitting executive.

and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended. Such information shall not be incorporated by reference into any filing under the Securities Act of 1933, as amended, except as may be expressly set forth in a specific filing. Exhibit No. Description 99.1 Second quarter 2024 earnings presentation of BrightSphere Investment Group Inc. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document) SIGNATURE Purs…

and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended. Such information shall not be incorporated by reference into any filing under the Securities Act of 1933, as amended, except as may be expressly set forth in a specific filing. Exhibit No. Description 99.1 First quarter 2024 earnings presentation of BrightSphere Investment Group Inc. 104 Cover Page Interactive Data File (embedded within the Inline XBRL document) SIGNATURE Pursu…