Buckhannon Bd. & Care Home, Inc. v. West Virginia Dep’t. of Health & Human Res. , 532 U.S. 598, 605, 121 S.Ct. 1835, 149 L.Ed.2d 855 (2001). We then held, in Oregon Nat. Desert Ass’n v. Locke , 572 F.3d 610, 614 (9th Cir. 2009), that Buckhannon , by analogy, would also apply to FOIA and, therefore, abrogated our decision in Church of Scientology. But, as we explained in Locke , in 2007 Congress "modified FOIA’s provision for the recovery of attorney fees to ensure that FOIA complainants who relied on the catalyst theory to obtain an award of attorney fees would not be subject to the Buckhannon proscription."

An award of attorney's fees or costs, or both, under the FOIA requires a plaintiff to "demonstrate both eligibility and entitlement to the award." Or. Natural Desert Ass'n v. Locke, 572 F.3d 610, 614 (9th Cir. 2009) (citation omitted). Eligibility requires a showing that a plaintiff "has `substantially prevailed' on his claim."

Once a court determines a party is eligible for an award, it exercises its "discretion to determine whether the plaintiff is entitled to fees." Oregon Nat. Desert Ass'n v. Locke , 572 F.3d 610, 614 (9th Cir. 2009) (emphasis added); see alsoChurch of Scientology , 700 F.2d at 489 (entitlement to an award of fees under FOIA is a separate analysis; a "determination of eligibility does not automatically entitle the plaintiff to attorney's fees."). In making this determination, courts consider "(1) the benefit to the public, if any, deriving from the case; (2) the commercial benefit to the complainant; (3) the nature of the complainant's interest in the records sought; and (4) whether the government's withholding of the records sought had a reasonable basis in law."

Once a court deems a party eligible to recover fees and costs, it then exercises its "discretion to determine whether the plaintiff is entitled to fees." Oregon Natural Desert Ass'n v. Locke, 572 F.3d 610, 614 (9th Cir. 2009) (citing Long v. U.S. I.R.S., 932 F.2d 1309, 1313 (9th Cir. 1991)). To determine whether a party is entitled to fees, a court must evaluate a number of equitable factors, including (1) the public benefit resulting from FOIA disclosures in the case, (2) the commercial benefit to the party resulting from the disclosures, (3) the nature of the party's interest in the disclosed records, and (4) whether the government's rationale for withholding the records had a reasonable basis in law.

On review, the Ninth Circuit agreed. .572 F.3d 610, 618 (9th Cir.2009).See id.; see also15 C.F.R. § 4.5(a) (prior to amendment).

Circuit courts interpreted Buckhannon's holding to apply in cases brought under FOIA. See Oil, Chem Atomic Workers Int'l Union, AFL-CIO v Dept of Energy, 288 F3d 452, 456-57 (DC Cir 2002); Union of Needletrades, Indus Textile Employees, AFL-CIO v INS, 336 F3d 200, 203 (2d Cir 2003); Oregon Natural Desert Ass'n v Locke, 572 F3d 610, 616-17 (9th Cir 2009) (agreeing with DC Circuit and Second Circuit that prior to the 2007 FOIA amendments, Buckhannon precluded FOIA plaintiffs from recovering fees under the catalyst theory). Congress responded to Buckhannon by amending FOIA in 2007 to revive the catalyst theory in FOIA cases.

Further, Debtor did not argue that dismissal of the claims for injunctive relief, declaratory relief, and unjust enrichment was error in its opening brief on appeal, and any such argument is therefore waived. Ore. Natural Desert Ass'n v. Locke, 572 F.3d 610, 614 n. 3 (9th Cir.2009) (“this court will not address claims not argued in the opening brief”)

Shortly thereafter, however, Congress amended FOIA to state that "a complainant has substantially prevailed if the complainant has obtained relief through either-(I) a judicial order, or an enforceable written agreement or consent degree; or (II) a voluntary or unilateral change in position by the agency, if the complainant's claim in not insubstantial." 5 U.S.C. § 552(a) (4) (E) (ii); see also Or. Nat. Desert Ass'n v. Locke, 572 F.3d 610, 614-15 (9th Cir. 2009) . Several circuits since have interpreted the amendment as reinstating the pre-Buckhannon catalyst theory of recovery in the FOIA context.

Although we review a district court's ultimate decision regarding whether to award attorney fees for abuse of discretion, we review de novo whether the district court applied the correct legal standard. Or. Nat. Desert Ass'n v. Locke , 572 F.3d 610, 613–14 (9th Cir. 2009) ; see alsoGrand Canyon Tr. v. Bernhardt , 947 F.3d 94, 96–97 (D.C. Cir. 2020) (per curiam) (explaining that the district court's determination regarding fee eligibility is reviewed de novo to the extent that it "rest[ed] on an interpretation of the statutory terms that define eligibility for an award" (citation omitted)). III.

Section 552(a)(4)(E)(ii) overruled UNITE and OCAW's extension of Buckhannon to FOIA suits. See Or. Natural Desert Ass'n v. Locke, 572 F.3d 610, 616-18 (9th Cir. 2009). Determining that Buckhannon applied to FOIA suits pending at the enactment of the OPEN Government Act, the district court concluded that to apply FOIA's new fee-shifting provision to Zarcon's pending request for fees would be impermissibly retroactive and rejected Zarcon's request.