Neither pre-judgment nor post-judgment interest is recoverable against the United States, except where the liability is imposed by statute or assumed by contract. 28 U.S.C. § 2516(a); United States v. New York Rayon Importing Co., 329 U.S. 654, 659 (1947); United States v. Thayer-West Point Hotel Co., 329 U.S. 585 (1947); Jacobs v. United States, 290 U.S. 13 (1933); United States v. Worley, 281 U.S. 339, 341 (1930).
In cases brought under the Suits in Admiralty Act, interest shall be at 4 percent per year or at any rate stipulated to by contract and it shall run, as ordered by the court, from the date the complaint is filed. 46 U.S.C. § 743. See Stoddard v. Ling-Temco-Vought, Inc., 513 F. Supp. 314, 330 (C.D. Cal. 1980); Richmond Marine Panama, S.A. v. United States, 350 F. Supp. 1210, 1220 (S.D.N.Y. 1972). In suits under the Public Vessels Act, no pre-judgment interest may be awarded unless expressly provided for by contract. 46 U.S.C. § 782. See Blevins v. United States, 769 F.2d 175 (4th Cir. 1985); Firth v. United States, 554 F.2d 990, 996 n. 10 (9th Cir. 1977); Stevens Institute of Technology v. United States, 396 F. Supp. 986, 992 (S.D.N.Y. 1975). Interest prior to judgment is expressly denied by the Federal Tort Claims Act. 28 U.S.C. § 2674.
The award of post judgment interest is governed in district courts by 28 U.S.C. §§ 1961, 2414, 2516 and 31 U.S.C. § 1304. The rate of interest is set forth in 28 U.S.C. § 1961(a). In cases brought under the Suits in Admiralty Act the rate of post-judgment interest is 4 per cent per year. See FTCA Monograph entitled "Prejudgment and Postjudgment Interest in Federal Tort Claims Act Litigation." No interest is allowed on any judgment where the government does not appeal. Where the government unsuccessfully appeals a judgment of a district court or a regional court of appeals, interest is allowed from the date the opposing party files the district court judgment with the Comptroller General through the day before the date of the mandate of affirmance by the court of appeals. 31 U.S.C. § 1304(b). Judgments on claims brought against the United States in the Court of Federal Claims bear interest only under a contract or a statute which expressly provides for interest. 28 U.S.C. § 2516(a). In cases brought against the United States in the Court of Federal Claims under the Contract Disputes Clause, a successful contractor may collect interest from the date the contracting officer receives the original claim submitted pursuant to 41 U.S.C. § 605(a) of the CDA until payment thereof. In such case the interest is paid at the rate established by the Secretary of the Treasury pursuant to Public Law 92-41 (85 Stat. 97) for the Renegotiation Board.
For additional information, and particularly where an appeal is taken from a district court judgment to the Court of Appeals for the Federal Circuit, see the Commercial Litigation Branch Monograph "Interest on Claims By and Against the Government" (June 1984).