The Hackett Group, Inc. Shareholder Meeting Notice The Hackett Group, Inc.’s Annual Meeting of Shareholders will be held on May 2, 2024 at The Hackett Group, Inc. Company Headquarters, 1001 Brickell Bay Drive, 30th Floor, Miami, Florida at 11:00 a.m., Local Time. Proposals to be voted on at the meeting are listed below along with the Board of Directors’ recommendations. The Board of Directors recommend a vote FOR the nominees and FOR Proposals 2, 3 and 4: 1. Election of Directors: 01 - Maria A. Bofill 02 - David N. Dungan 03 - Richard N. Hamlin 2. To approve an amendment to the Company’s 1998 Stock Option and Incentive Plan (the “Plan”) to (i) increase the sublimit under the Plan for restricted stock and restricted stock unit issuances by 1,200,000 shares, and (ii) increase the total number of shares authorized for issuance under the Plan by 1,200,000 shares; 3. To approve, in an advisory vote, the Company’s executive compensation; 4. To ratify the appointment of RSM US LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 27, 2024 PLEASE NOTE – YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must go online or request a paper copy of the proxy materials to receive a proxy card. If you wish to attend and vote at the meeting, please bring this notice with you. Here’s how to order a copy of the proxy materials and select delivery preferences: Current and future delivery requests can be submitted using the options below. If you request an email copy, you will receive an email with a link to the current meeting materials. PLEASE NOTE: You must use the number in the shaded bar on the reverse side when requesting a copy of the proxy materials. Internet – Go to www.investorvote.com/hckt. Phone – Call us free of charge at 1-866-641-4276. Email – Send an email to investorvote@computershare.com with “Proxy Materials The Hackett Group Inc.” in the subject line. Include your full name and address, plus the number located in the shaded bar on the reverse side, and state that you want a paper copy of the meeting materials. To facilitate timely delivery, requests for a paper copy of proxy materials must be received by April 22, 2024.