4 CFR § 21.9 - Time for decision by GAO.
(a) GAO shall issue a decision on a protest within 100 days after it is filed. GAO will attempt to resolve a request for recommendation for reimbursement of protest costs under § 21.8(e), a request for recommendation on the amount of protest costs under § 21.8(f), or a request for reconsideration under § 21.14 within 100 days after the request is filed.
(c) GAO, to the maximum extent practicable, shall resolve a timely supplemental protest adding one or more new grounds to an existing protest, or a timely amended protest, within the time limit established in paragraph (a) of this section for decision on the initial protest. If a supplemental or an amended protest cannot be resolved within that time limit, GAO may resolve the supplemental or amended protest using the express option procedures in § 21.10.