In sealed bidding procurements, an invitation for bid (IFB) provides all non-price terms and conditions of the prospective contract. Bidders responding to IFBs must acknowledge its terms, including all amendments. Failure to acknowledge an amendment may result in the bid being found nonresponsive if the amendment is deemed material to the IFB. An amendment is considered material if it imposes legal obligations on the bidders that were not contained in the original solicitation. Furthermore, an amendment is material if it has more than a negligible impact on price, quality, or delivery. If a bidder fails to acknowledge a non-material amendment, the procuring agency may waive the lack of acknowledgment as a minor informality. Alternatively, if it is more advantageous to the agency, the bidder may be given an opportunity to cure the deficiency and acknowledge the non-material amendment. However, a lack of acknowledgment of a material amendment is not waivable because, without the acknowledgment, the bidder is not legally obligated to meet the government’s needs even after the government accepts its bid. Thus, an awardee’s failure to acknowledge a material amendment is a protestable issue post-award. Notably, whether an amendment is material is a fact-specific inquiry resolved based on the circumstances of each case.

In B-423796, a decision issued on February 5, 2026, the Government Accountability Office (GAO) sustained a post-award bid protest after finding that the awardee had failed to acknowledge a material amendment. The U.S. Army Corps of Engineers (USACE) issued the underlying IFB for the construction of a steel-pile offloading platform to provide access to a disposal facility in St. Clair County, Michigan. The IFB contemplated a fixed-price award to the lowest-price bidder found responsible and responsive. The government issued three amendments to the IFB, the third of which revised the plan sheets by slightly increasing the size and weight of the sheet pile cap. The amendment also updated the wage determination to include new labor and fringe rates. The awardee submitted the lowest bid of $1.89 million, whereas the protester submitted the second-lowest bid of $2.3 million. Upon noticing that the awardee had failed to acknowledge the third amendment, the government notified the awardee, who responded by submitting a signed version of the amendment. While the agency initially found the awardee’s bid non-responsive, it later revised its determination because the wage determination was inapplicable to the staffing on the procurement, and the change in steel pile cap size resulted in only a negligible $21,000 increase in price.

Following the revised determination and award, the protester filed its protest, contending that the agency unreasonably determined that the awardee’s failure to acknowledge the third amendment was a minor informality. The GAO began its analysis by first disagreeing with the protester that the awardee’s failure to acknowledge the wage determination in the third IFB amendment was a material defect. The decision explained that, while even minimal revisions to wage rates mandated by the Davis-Bacon Act require the bidder's acknowledgment, such acknowledgment is mandatory only when there is a reasonable possibility that the relevant services will be required during contract performance. Here, USACE determined that the wage determination in the third amendment was inapplicable to the current contract because it increased wage rates for landscape workers, which were not required for contract performance. Moreover, the awardee did not propose using any landscape workers on the contract. Thus, the wage determination portion of the third IFB amendment was deemed not material and did not require acknowledgment by the awardee because it did not impact the wage of a trade to be employed on the contract.

Next, the GAO reviewed the portion of the third amendment concerning the larger steel-pile channel cap, and this time, agreed with the protester. The decision noted that the larger channel cap was necessary to accommodate the dimensional irregularities of the sheet pile walls that were to be used during performance. Furthermore, the contracting officer described this change as substantive. Accordingly, the IFB, as amended by the third amendment, changed the contract specifications, and the portion of the third amendment concerning the larger steel pile channel cap was material because it had a more than negligible impact on delivery. The GAO rejected the agency’s argument that the awardee’s failure to acknowledge the revised sheet pile cap size was not a material defect because its effect on price was negligible. Although the amendment’s effect on price is a factor in determining its materiality for the purposes of the need for the bidder’s acknowledgment, it is not a dispositive factor. Since the amendment had a more than negligible effect on delivery, failing to acknowledge it was not merely a minor procedural defect but a material one, even though the impact on price may have been negligible. Consequently, the GAO upheld the protest, noting that the awardee’s bid should have been rejected as nonresponsive and recommended that the award be terminated for the government’s convenience.

In sealed-bidding procurements, the government uses IFBs in a uniform contract format, which may be amended using Standard Form 30. IFB bidders must acknowledge all amendments or run the risk of their bid not being found responsive if an unacknowledged amendment is deemed material. While a failure to acknowledge a non-material amendment may be waived or cured, a material amendment must be acknowledged. An amendment is material if it has more than a negligible impact on price, quality, or delivery. It is worth noting that none of these factors is individually dispositive of whether an amendment is material. This is because the materiality of a particular amendment is a fact-specific inquiry to be determined on a case-by-case basis. If an amendment changes the performance requirements regarding quality or delivery, or substantially changes the price, it will likely be considered material. In contrast, if the amendment has no or negligible impact on the prospective contractor’s responsibilities or price, it is likely not material. Finally, as demonstrated by the protest described above, even if a portion of an IFB amendment is deemed material, acknowledgment is necessary, as without it the bidder is not legally bound to meet the government’s needs.

This Bid Protest Insight is provided as a general summary of the applicable law in the practice area and does not constitute legal advice. Contractors wishing to learn more are encouraged to consult the TILLIT LAW PLLC Client Portal or Contact Us to determine how the law would apply in a specific situation.