UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K Current Report Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): September 18, 2003 ALLMERICA FINANCIAL CORPORATION (Exact name of registrant as specified in its charter) Delaware 1-13754 04-3263626 (State or other jurisdic- (Commission File Number) (I.R.S. Employer tion of incorporation) Identification Number) 440 Lincoln Street, Worcester, Massachusetts 01653 (Address of principal executive offices) (Zip Code) (508) 855-1000 (Registrant's telephone number, including area code) Item 9. Regulation FD Disclosure. On September 18, 2003, Allmerica Financial Corporation issued a press release announcing that Robert P. Restrepo, Jr. has resigned as president of the Allmerica Property and Casualty Companies. The release is furnished as Exhibit 99.1 hereto. 2 SIGNATURES Pursuant to the requirements of the Securities and Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Allmerica Financial Corporation Registrant By: /s/ Edward J. Parry III ----------------------- Edward J. Parry III Chief Financial Officer, Senior Vice President and Principal Accounting Officer Date: September 18, 2003 3