13F-HR/A 1 acadian_13fhra.txt UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 13F FORM 13F COVER PAGE Report for the Calendar Year or Quarter Ended: September 30, 2009 Check here if Amendment [X]; Amendment Number: 1__ This Amendment (Check only one.) [ ] is a restatement. [X] adds new holdings entries. This Filing Lists Securities Holdings Reported On The Form 13F Filed On November 12, 2009 Pursuant To A Request For Confidential Treatment And For Which That Request Was Denied On February 14, 2011. Institutional Investment Manager Filing this Report: Name: Acadian Asset Management LLC Address: One Post Office Square, 20th Floor Boston, MA 02109 Form 13F File Number: 028-05990 The institutional investment manager filing this report and the person by whom it is signed hereby represent that the person signing the report is authorized to submit it, that all information contained herein is true, correct and complete, and that it is understood that all required items, statements, schedules, lists, and tables, are considered integral parts of this form. Person Signing this Report on Behalf of Reporting Manager: Name: Cynthia Kelly Title: Senior Compliance Officer Phone: (617) 598-6837 Signature, Place, and Date of Signing: /s/ Cynthia Kelly Boston, Massachusetts February 22, 2011 [Signature] [City, State] [Date] Report Type (Check only one.): [X] 13F HOLDINGS REPORT. (Check here if all holdings of this reporting manager are reported in this report.) [ ] 13F NOTICE. (Check here if no holdings reported are in this report, and all holdings are reported by another reporting manager(s).) [ ] 13F COMBINATION REPORT. (Check here if a portion of the holdings for this reporting manager are reported in this report and a portion are by other reporting manager(s).) FORM 13F SUMMARY PAGE Report Summary: Number of Other Included Managers: 1 Form 13F Information Table Entry Total: 1 Form 13F Information Table Value Total: $1 (thousands) List of Other Included Managers: Provide a numbered list of the name(s) and Form 13F file number(s) of all institutional investment managers with respect to which this report is filed, other than the manager filing this report. No. Form 13F File Number Name 1 028-11931 Old Mutual (US) Holdings Inc.
Voting Authority ---------------- Title Value Shares/ Sh/ Put/ Invstmt Other Name of Issuer of Class CUSIP (x$1000) Prn Amt Prn Call Dscretn Managers Sole Shared None -------------- -------- ----- ------ ------- --- ---- ------- -------- ----- ------ ---- LIFE SCIENCES RESH INC COM 53216910 1 73 SH Defined 1 73 0 0