On April 15, 2016, the Government Accountability Office (GAO) issued a proposed rule in the Federal Register that would amend its current bid protest regulations, codified at 4 C.F.R. Part 21.1 The proposed rule adds a degree of formality to the protest process, including a modest filing fee and the use of an electronic filing system similar to the one used by most federal courts. Overall, however, the rule mainly codifies or clarifies existing protest practices, with certain limited exceptions. We summarize the key proposed amendments below.