GAO’s bid protest timeliness rules are strict. Even a strong protest can be dismissed if it is not filed within the deadline established by GAO regulations. In certain procurements, required debriefings can affect protest deadlines while voluntary debriefings or brief explanations in other types of procurements do not toll deadlines.

In Hendall Inc., B-423714.5 (Oct. 1, 2026), the Government Accountability Office (GAO) dismissed a bid protest as untimely because it was filed more than 10 days after the protester knew, or should have known, its grounds for protest. The protester argued that its protest was timely because it was filed within 10 days of the agency’s “brief explanation” of the award decision. GAO rejected that argument and ruled that the protest clock started earlier, when Hendall received notice of the award.

The decision is a reminder that a contractor cannot assume that a post-award explanation tolls the GAO deadline. The debriefing exception applies only when the procurement is conducted on the basis of competitive proposals and the debriefing is required. For a Federal Supply Schedule (FSS) procurement, a requested brief explanation does not itself reset the clock. Below, we discuss the case and offer practical guidance for contractors who receive a notice of non-award.

Hendall Inc., B-423714.5 (Oct. 1, 2026)

The Centers for Medicare and Medicaid Services (CMS) issued a request for quotations (RFQ) under the General Services Administration’s (GSA) FSS program, using the streamlined ordering procedures of Federal Acquisition Regulation (FAR) subpart 8.4, for management of its Comprehensive Error Rate Testing program. The procurement had a long history of protests and corrective action.

After Hendall was excluded from the competitive range, it protested to GAO in August 2025. In that protest, Hendall argued the agency conducted an impermissible price realism analysis. CMS took corrective action and reopened discussions with Hendall. In November 2025, CMS selected Serco, Inc. for award. Hendall protested again on December 1, 2025, and GAO dismissed that protest after another vendor filed a related protest at the U.S. Court of Federal Claims (COFC). CMS then took corrective action in the COFC protest and reevaluated the quotations. On May 28, 2026, CMS notified Hendall that it had not been selected for award. Hendall requested a brief explanation, which CMS provided on June 16. Hendall filed its protest with GAO on June 26, 2026.

GAO found Hendall’s protest untimely, applying the strict timeliness rules in its bid protest regulations. Under GAO’s bid protest regulations, protests not based on alleged improprieties in the solicitation itself must be filed within 10 days after the protester knew or should have known the basis for protest, whichever is earlier.[1] There is one important exception. For procurements conducted on the basis of competitive proposals where a debriefing is requested and required, such as FAR part 15 negotiated procurements and, in some cases, FAR subpart 16.5 task order competitions, a protest must be filed within 10 days after the debriefing is held.

Because CMS conducted the procurement under FAR subpart 8.4, the FAR part 15 debriefing requirements did not apply. In FSS procurements, the FAR requires agencies to provide only a “brief explanation of the basis” for the award decision, and only upon request. GAO explained that a brief explanation is not a required debriefing and is no different from any other source of information about the award for timeliness purposes. As a result, GAO held that Hendall’s protest clock began on May 28, 2026, when Hendall received notice that it had not been selected for award.

Hendall argued that it had no basis for a “knowledgeable or supportable” protest until it received the June 16 brief explanation. GAO disagreed, noting that a protester “need not await perfect knowledge” and may not delay filing until it can detail every possible protest ground. GAO further observed that Hendall already knew of both of its protest grounds—challenges to the agency’s price realism and tradeoff analyses—because it had raised them in its prior protests.

Key Takeaways for Contractors

GAO’s decision in Hendall underscores the importance of understanding the deadline for protest and whether a required debriefing can extend it. Contractors should keep the following points in mind:

  • Consult counsel immediately after receiving a notice of non-award to assess timeliness, debriefing options, and potential protest grounds. Experienced counsel can review the timeline, including the award notice, which may have already started the protest clock. Counsel can then advise on whether to request a debriefing, key questions, protest options and forums, and help evaluate the strength of potential protest grounds early.
  • Understand whether a debriefing is required. This distinction can determine whether a protest survives. In FAR part 15 procurements, and in some FAR subpart 16.5 task order competitions, a required debriefing that is timely requested can extend the GAO filing deadline to 10 days after the debriefing is held.[2] By contrast, voluntary debriefings, brief explanations, and other information provided by agencies do not extend protest deadlines.
  • Do not wait for additional information if you already know your protest grounds. GAO does not require perfect knowledge before a protest is filed. If the award notice, or prior protests and corrective action, already reveal the basis for a challenge, the 10-day clock is likely already running

The bottom line is that contractors considering a protest should contact counsel immediately when an unfavorable award notice arrives. This is especially important in an FSS or other non-FAR part 15 procurement, where the protest clock has likely started and time is limited.

[1] 4 C.F.R. § 21.2(a)(2)

[2] The automatic Competition in Contracting Act (CICA) stay deadline is separate from GAO’s 10-day timeliness rule. In a post-award context, a GAO protest must generally be filed within 5 days after a required debriefing in order to trigger a CICA stay. 31 USC § 3553(d)(4).