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): December 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 No.) 440 Lincoln Street, Worcester, Massachusetts 01653 (Address of principal executive offices) (Zip Code) (508) 855-1000 (Registrant's telephone number, including area code) Item 7. Financial Statements and Exhibits. (a.) Not applicable. (b.) Not applicable. (c.) Exhibits. Exhibit 99.1 Notice to Directors and Section 16 Officers, dated December 18, 2003. Item 11. Temporary Suspension Of Trading Under Registrant's Employee Benefit Plan On or after October 28, 2003, Allmerica Financial Corporation (the "Company") received notice required under Section 101(i)(2)(E) of the Employment Retirement Income Security Act of 1974 with regard to blackout periods under the Allmerica Financial Employees' 401(k) Matched Savings Plan, Allmerica Financial Agents' Retirement Plan, Allmerica Financial Cash Balance Pension Plan, The Allmerica Financial Cash Balance Pension Plan Excess Benefit Plan, The Allmerica Financial Progress Sharing Excess Benefit Plan, The Allmerica Financial Agents' Retirement Excess Benefit Plan, The Allmerica Financial Agents' Pension Excess Benefit Plan, The Allmerica Financial Executive Deferred Compensation Plan, The Allmerica Financial Short Term Deferred Management Incentive Comp Plan, The Allmerica Financial Long Term Deferred Management Incentive Comp Plan, and The Allmerica Financial Deferred Dividends Plan (the "Blackout Period"). On December 18, 2003, the Company sent a notice to its directors and officers subject to Section 16 of the Securities Exchange Act of 1934, as amended, informing them that the Blackout Period will commence after 4:00 p.m. ET, Monday, December 29, 2003 and is expected to end during the week of Sunday, January 18, 2004, and restricting them from trading in any AFC stock during such period and until the end of the regularly scheduled year end trading blackout. A copy of the notice sent to directors and executive officers is attached as Exhibit 99.1 hereto and is incorporated by reference. During the Blackout Period and for a two year period after the end of the Blackout Period, a security holder or other interested person may obtain, without charge, the actual start and end dates of the Blackout Period by contacting the Secretary of Allmerica Financial Corporation, 440 Lincoln Street, Worcester, MA 01653, (508) 855-2319. 2 SIGNATURES Pursuant to the requirements of the Securities 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, Executive Vice President and Principal Accounting Officer Date: December 18, 2003 3 Exhibit Index Exhibit 99.1 Notice to Directors and Section 16 Officers, dated December 18, 2003. 4