By law, a GAO protest must be filed by an interested party. An interested party is an actual or prospective bidder or offeror whose direct economic interest would be impacted by the award of a contract or by the failure to award a contract. Before bid opening or the closing date for receipt of proposals, a protestor must be a prospective bidder or offeror with a direct economic interest in the procurement. This generally means that a bidder or offeror has expressed an interest in competing and is capable of performing the type of work that the solicitation requires. After bid opening or the submission of proposals, a protestor must be an actual bidder or offeror with a direct economic interest in the procurement. This generally means a bidder or offeror who would be in line for award if the protest were sustained. A protestor who cannot receive an award if it prevails on the merits of its protest is not an interested party. In some cases, a high-priced bidder might be able to demonstrate that all lower-priced bidders are ineligible for award, thus becoming the next-in-line for award. In a “best value” negotiated procurement, the GAO determines whether a protestor is an interested party by examining the probable result if the protest is successful. This means that an actual offeror, who is not in line for award, is an interested party if it would regain the opportunity to compete if the protest is sustained.