v3.25.3

Cover Page	Oct. 28, 2025
Entity Information [Line Items]
Document Type	8-K
Document Period End Date	Oct. 28, 2025
Entity Registrant Name	Acadian Asset Management Inc.
Entity Incorporation, State or Country Code	DE
Entity File Number	001-38979
Entity Tax Identification Number	47-1121020
Entity Address, Address Line One	200 State Street
Entity Address, Address Line Two	Suite 601A
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02109
City Area Code	617
Local Phone Number	369-7300
Written Communications	false
Soliciting Material	false
Pre-commencement Tender Offer	false
Pre-commencement Issuer Tender Offer	false
Entity Emerging Growth Company	false
Entity Central Index Key	0001748824
Amendment Flag	false
Common stock, par value $0.001 per share
Entity Information [Line Items]
Title of 12(b) Security	Common stock, par value $0.001 per share
Trading Symbol	AAMI
Security Exchange Name	NYSE
4.800% Notes due 2026
Entity Information [Line Items]
Title of 12(b) Security	4.800% Notes due 2026
Trading Symbol	AAMI 26
Security Exchange Name	NYSE

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For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

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The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

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Address Line 1 such as Attn, Building Name, Street Name

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Name of the City or Town

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Name of the state or province.

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A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

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Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

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The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

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The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

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Local phone number for entity.

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Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.

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Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.

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Trading symbol of an instrument as listed on an exchange.

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Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.

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Acadian Asset Management Inc. 8-K