Opinion

Justice O'CONNOR delivered the opinion of the Court.

We are called upon in these cases to decide the applicable rate of postjudgment interest and the date from which postjudgment interest should be calculated pursuant to the federal postjudgment interest statute. 28 U.S.C. § 1961 (1982 ed.) (amended).

I

Respondents (Bonjorno) were the sole stockholders of now defunct Columbia Metal Culvert Co., Inc., which was at one time a fabricator of aluminum drainage pipe in Vineland, New Jersey. Bonjorno brought suit against petitioners (Kaiser) in the United States District Court for the Eastern District of Pennsylvania on the theory that Kaiser had monopolized the market for aluminum drainage pipe in the Mid-Atlantic region of the United States in violation of the Sherman Act. 26 Stat. 209, as amended, 15 U.S.C. §§ 1 and 2 (1988).

At the first trial, the District Court entered a directed verdict for Kaiser. The Court of Appeals for the Third Circuit reversed, holding that there was sufficient evidence for the case to go to the jury. Columbia Metal Culvert Co. v. Kaiser Aluminum & Chemical Corp., 579 F.2d 20, 37 (1978). On August 21, 1979, a second trial resulted in a jury verdict in respondents' favor in the trebled amount of $5,445,000. The judgment was entered on August 22, 1979. The District Court held that the evidence did not support the jury's damages award and granted petitioners' motion for a new trial as to damages only. 518 F.Supp. 102, 109, 119 (ED Pa.1981). A limited retrial on damages resulted in a jury award on December 2, 1981, in the trebled amount of $9,567,939. Judgment was entered on December 4, 1981. On January 17, 1983, the District Court granted Kaiser's motion for judgment notwithstanding the verdict as to a portion of the damages awarded by the jury. 559 F.Supp. 922 (ED Pa.1983). Bonjorno appealed the reduction in damages, and the Court of Appeals reversed the District Court's partial grant of petitioners' motion for judgment notwithstanding the verdict as to damages, vacated the judgment, and reinstated and affirmed the judgment entered on December 4, 1981. 752 F.2d 802, 815 (CA3 1984). Kaiser's petition for rehearing in banc was denied, as was its subsequent petition for certiorari to this Court. 477 U.S. 908 (1986).

The Court of Appeals did not refer in its opinion to the allowance of postjudgment interest; Bonjorno petitioned the Court of Appeals for instructions regarding interest to be included in the mandate pursuant to Federal Rule of Appellate Procedure 37, which permits courts of appeal to direct payment of interest commencing with the entry of judgment in the district court unless otherwise provided by law. Before the Court of Appeals could rule on the petition, the parties entered into a stipulation providing that the District Court first address all issues of interest allowable under 28 U.S.C. § 1961 and Federal Rule of Appellate Procedure 37. The Court of Appeals approved the stipulation and certified the judgment in lieu of a formal mandate. On July 1, 1986, the mandate of the Court of Appeals, stayed pending disposition of Kaiser's petition for a writ of certiorari with this Court, was issued to the District Court. On July 3, 1986, Kaiser paid Bonjorno $9,567,939, the trebled amount of damages awarded by the jury on December 2, 1981.

The federal statute governing awards of postjudgment interest in effect at the time Bonjorno filed the complaint on January 17, 1974, and until October 1, 1982, provided:

Interest shall be allowed on any money judgment in a civil case recovered in a district court. Execution therefor may be levied by the marshal, in any case where, by the law of the State in which such court is held, execution may be levied from interest on judgments recovered in the courts of the State. Such interest shall be calculated from the date of the entry of judgment, at the rate allowed by State law.

28 U.S.C. § 1961 (1976 ed.).

On April 2, 1982, Congress passed the Federal Courts Improvement Act of 1982, Pub.L. 97-164, 96 Stat. 25, § 302 of which amended 28 U.S.C. § 1961. To permit courts and the bar to prepare themselves for the changes wrought by the Act, Congress delayed its effective date by six months to October 1, 1982. § 402, 96 Stat. 57. The amended version provides:

(a) Interest shall be allowed on any money judgment in a civil case recovered in a district court. Execution therefor may be levied by the marshal, in any case where, by the law of the State in which such court is held, execution may be levied for interest on judgments recovered in the courts of the State. Such interest shall be calculated from the date of the entry of the judgment, at a rate equal to the coupon issue yield equivalent (as determined by the Secretary of the Treasury) of the average accepted auction price for the last auction of fifty-two week United States Treasury bills settled immediately prior to the date of the judgment. The Director of the Administrative Office of the United States Courts shall distribute notice of that rate and any changes in it to all Federal judges.

(b) Interest shall be computed daily to the date of payment except as provided in section 2516(b) of this title and section 1304(b) of title 31, and shall be compounded annually.

28 U.S.C. § 1961 (1982 ed.).

The District Court held that 28 U.S.C. § 1961 required interest to be calculated from December 2, 1981, the date of the damages verdict on which the correct judgment would have been entered but for the District Court's erroneous partial grant of judgment notwithstanding the verdict. See Poleto v. Consolidated Rail Corp., 826 F.2d 1270, 1280 (CA3 1987) (interest calculated from date of verdict rather than judgment); Institutionalized Juveniles v. Secretary of Public Welfare, 758 F.2d 897, 927 (CA3 1985) (interest calculated from date correct award would have been entered but for the District Court's error). The District Court rejected Bonjorno's argument that the amended version of § 1961 should be applied for the purpose of determining the applicable interest rate under Bradley v. Richmond School Board, 416 U. S. 696 (1974) (courts are to apply the law in effect at the time a court renders its decision unless such application results in manifest injustice or runs contrary to congressional intent), reasoning that application of amended § 1961 would result in manifest injustice. Thus, the District Court applied the earlier version of § 1961, which set the interest rate allowed by state law. At that time, Pennsylvania provided for a 6 percent rate of interest. 42 Pa.Cons.Stat. § 8101 (1988); Pa.Stat.Ann., Tit. 41, § 202 (Purdon Supp.1989).

The Court of Appeals affirmed the District Court's determination that interest should be calculated from December 2, 1981, but reversed the District Court on the issue of which version of § 1961 applied. The Court of Appeals invoked the rule in Bradley, supra, that a court should apply the law in effect at the time a court renders its decision, but noted that

the Bradley presumption of applying the law in effect at the time a court renders its decision in the absence of contrary legislative intent seems inconsistent with the longstanding rule of statutory construction that statutes are presumed to have only 'prospective' effect and will be given 'retroactive' effect only if there is affirmative legislative direction to do so.

865 F.2d 566, 573 (CA3 1989). Finding the legislative history unclear and that application of the amended § 1961 would not result in manifest injustice, the Court of Appeals held that the Bradley presumption required application of the amended § 1961 in effect at the time the District Court and the Court of Appeals reached their decisions.

The Court of Appeals acknowledged that its decision was in conflict with decisions on the same issue in other Courts of Appeal. Three approaches have been followed by the Courts of Appeal: (1) the amended version of § 1961 is applied to judgments entered after the effective date, see United States v. Dollar Rent A Car Systems, Inc., 712 F.2d 938, 940, n. 5 (CA4 1983); Merit Ins. Co. v. Leatherby Ins. Co., 728 F.2d 943, 944 (CA7 1984), cert. denied, 469 U.S. 918 (1984); Litton Systems, Inc. v. American Tel. & Tel. Co., 746 F.2d 168, 174 (CA2 1984); Brooks v. United States, 757 F.2d 734, 741-742 (CA5 1985); (2) the amended version applies to judgments entered before the effective date for the duration of the postjudgment interest period, see R.W.T. v. Dalton, 712 F.2d 1225, 1234-1235 (CA8), cert. denied, 464 U.S. 1009 (1983); and (3) the amended version applies to judgments entered before the effective date but only for interest accruing in the period after the effective date. See Bailey v. Chattem, Inc., 838 F.2d 149, 155-156 (CA6), cert. denied, 486 U.S. 1059 (1988); Campbell v. United States, 809 F.2d 563, 577 (CA9 1987).

We granted certiorari, 491 U.S. 903 (1989), primarily to consider three questions: first, whether interest should be calculated from the date of verdict or the date of judgment; second, whether interest should be calculated from the date of a legally insufficient judgment; and third, the proper application of § 1961 to judgments entered before the effective date of amended § 1961.

II

A

Kaiser argues that the appropriate date from which interest should be calculated is the date of the entry of the later judgment, December 4, 1981, and not the date of the verdict, December 2, 1981. Both the Court of Appeals and the District Court held that postjudgment interest should be calculated from December 2, 1981, the date of verdict, relying on settled Third Circuit precedent. See Poleto v. Consolidated Rail Corp., 826 F.2d 1270, 1280 (1987) (interest calculated from date on which jury returns verdict on damages). The Courts of Appeal are split on this issue. Compare Millers' Nat'l Ins. Co., Chicago, Ill. v. Wichita Flour Mills Co., 257 F.2d 93, 104 (CA10 1958) (interest calculated from date of judgment) with Turner v. Japan Lines, Ltd., 702 F.2d 752 (CA9 1983) (interest calculated from date of verdict). Those courts who have determined that interest should run from the verdict have looked to the policy underlying the postjudgment interest statute -compensation of the plaintiff for the loss of the use of the money -in reaching their conclusion that interest should run from the date of the judgment despite the language of the statute. See, e.g., Poleto, supra. Cf. Note, Interest on Judgments in the Federal Courts, 64 Yale L.J. 1019, 1039 (1955) ("Allowance of interest from verdict [under state postjudgment statutes despite their plain language] is generally based on the defendant's fault in causing the delay in entry of judgment and on the desirability of fully compensating the plaintiff for the loss of use of his recovery").

The starting point for interpretation of a statute

is the language of the statute itself. Absent a clearly expressed legislative intention to the contrary, that language must ordinarily be regarded as conclusive.

Consumer Product Safety Comm'n v. GTE Sylvania, Inc., 447 U. S. 102, 447 U. S. 108 (1980).

By linking all postjudgment activity to the entry of a judgment, the courts have been provided a uniform time from which to determine postjudgment issues.

Comment, Post-Judgment Interest in Federal Courts, 37 Emory L.J. 495, 499 (1988). Both the original and the amended versions of § 1961 refer specifically to the "date of judgment," which indicates a date certain. Neither alludes to the date of the verdict, and there is no legislative history that would indicate congressional intent that interest run from the date of verdict rather than the date of judgment. Even though denial of interest from verdict to judgment may result in the plaintiff's bearing the burden of the loss of the use of the money from verdict to judgment, the allocation of the costs accruing from litigation is a matter for the legislature, not the courts. See Alyeska Pipeline Service Co. v. Wilderness Society, 421 U. S. 240, 421 U. S. 271 (1975). In light of the plain language and the absence of legislative intent to the contrary, we conclude that postjudgment interest properly runs from the date of the entry of judgment.

B

Bonjorno asserts, in its cross-petition, that the judgment from which interest should be calculated is not that entered in December, 1981, but rather the date of the judgment entered on August 22, 1979, the damages portion of which the District Court later found was not supported by the evidence. The District Court's determination that the jury's finding on damages was not supported by the evidence was not appealed by either party.

[T]he purpose of postjudgment interest is to compensate the successful plaintiff for being deprived of compensation for the loss from the time between the ascertainment of the damage and the payment by the defendant.

Poleto v. Consolidated Rail Corp., 826 F.2d at 1280. Where the judgment on damages was not supported by the evidence, the damages have not been "ascertained" in any meaningful way. It would be counterintuitive, to say the least, to believe that Congress intended postjudgment interest to be calculated from such a judgment. See FDIC v. Rocket Oil Co., 865 F.2d 1158 (CA10 1989) (postjudgment interest may not be calculated from judgment that was completely reversed).

Accordingly, we hold that the Court of Appeals properly rejected Bonjorno's contention that interest should be calculated from August 22, 1979, but erred in calculating interest from December 2, 1981, rather than December 4, 1981.

III

The Court in Bradley v. Richmond School Bd., 416 U. S. 696 (1974), faced the issue whether an attorney's fee statute that went into effect during the pendency of the appeal was to be applied by the appellate court. Relying on Thorpe v. Durham Housing Authority, 393 U. S. 268 (1969), the Court held that "a court is to apply the law in effect at the time it renders its decision." 416 U.S. at 416 U. S. 711. The Court derived this holding from a broad reading of United States v. Schooner Peggy, 1 Cranch 103 (1801), in which the following principles were articulated:

[I]f subsequent to the judgment, and before the decision of the appellate court, a law intervenes and positively changes the rule which governs, the law must be obeyed.... It is true that, in mere private cases between individuals, a court will and ought to struggle hard against a construction which will, by a retrospective operation, affect the rights of parties, but in great national concerns... the court must decide according to existing laws.

Id., 1 Cranch at 5 U. S. 110. Under the rule set forth in Schooner Peggy, an amendment to the law while a case was pending should be applied by the appellate court only if, "by its terms," the law was to be applied to pending cases. See Bradley, supra, 416 U.S. at 416 U. S. 712. In Thorpe, supra, the Court broadened the rule set forth in Schooner Peggy: "[E]ven where the intervening law does not explicitly recite that it is to be applied to pending cases, it is to be given recognition and effect." Bradley, supra, at 416 U. S. 715. As a means of softening the potentially harsh impact of this broadening retrospective application of congressional enactments, the Court recognized two exceptions to the presumption that courts are to apply the law in effect at the time of decision. The presumption does not govern where retrospective application would result in manifest injustice to one of the parties or where there is clear congressional intent to the contrary. See 416 U.S. at 416 U. S. 711. The Court of Appeals applied the Bradley test and held that the legislative history was ambiguous and that retrospective application of amended § 1961 did not result in manifest injustice.

In apparent tension with the rule articulated in Bradley, supra, is our recent reaffirmation of the generally accepted axiom that

[r]etroactivity is not favored in the law.... [C]ongressional enactments and administrative rules will not be construed to have retroactive effect unless their language requires this result.

Bowen v. Georgetown University Hospital, 488 U. S. 204, 488 U. S. 208 (1988). In Georgetown University Hospital, we held that the Department of Health and Human Services did not have the power to promulgate retroactive cost-limit rules, because authority to issue retroactive rules was not authorized by Congress in the Medicare Act. Id. at 488 U. S. 208 -216.

We need not in this case, however, reconcile the two lines of precedent represented by Bradley, supra, and Georgetown, supra, because, under either view, where the congressional intent is clear, it governs. See Bradley, supra, 416 U.S. at 416 U. S. 716 -717 (intervening statute applies retroactively unless a contrary intention appears); Georgetown, supra, 488 U.S. at 488 U. S. 208 (statute does not apply retroactively unless its language requires it). We conclude that the plain language of both the original and amended versions of § 1961 evidence clear congressional intent that amended § 1961 is not applicable to judgments entered before its effective date.

As both the original and the amended versions of § 1961 indicate, a court must consider two factors to determine how much postjudgment interest is owed: (1) the length of time the interest is to run, which requires identification of a starting point and an ending point, and (2) the interest rate at which the interest is to be computed. Section 1961, originally and as amended, provides the starting point -the date of the entry of judgment -and the interest rate. The termination point is set by the party who pays the judgment, and in general it may occur at any time following entry of judgment.

Under both versions of § 1961, the calculation of interest is inextricably tied to the date of the entry of judgment. Both provisions provide that the interest due "shall be calculated from the date of the entry of the judgment. " Indeed, even the calculation of the interest rate in amended § 1961 is tied to the judgment date:

interest shall be calculated... at a rate equal to the coupon issue yield equivalent... of the average accepted auction price for the last auction of fifty-two week United States Treasury bills settled immediately prior to the date of the judgment.

See Litton, 746 F.2d at 174 (calculation of rate tied to judgment date indicates Congress intended prospective application of amended § 1961).

The language of each version of the statute also directs that a single applicable rate of interest be applied to the judgment: the prior version refers to "the rate" and the amended version to "a rate." See Comment, 37 Emory L.J., at 532-633, n. 207 ("[P]lain language of the [amended version] indicates that only one interest rate will apply"). We think the most logical reading of the statute is that the interest rate for any particular judgment is to be determined as of the date of the judgment, and that is the single rate applicable for the duration of the interest accrual period.

Congress delayed the effective date on the amended version by six months to permit courts and attorneys to prepare for the change in the law. S.Rep. No. 97-275, p. 32 (1981) ("[T]he delay is intended to provide time for planning the transition and for permitting the bar to become familiar with the provisions"). Thus, at the very least, the amended version cannot be applied before the effective date of 1982. See Campbell v. United States, 809 F.2d 563, 574 (CA9 1987) ("[T]he literal terms of the Senate committee report... preclude imposition of interest at the T-bill rate... in the period prior to the enactment date"). Given that the plain language only admits of one relevant interest rate and that the amended rate cannot be applied before the effective date of October 1, 1982, we conclude that the interest rate to be applied to judgments entered before October 1, 1982, is the rate set pursuant to the prior version of § 1961.

In the brief legislative history available, there is a single stated purpose for Congress' alteration of the interest rate from the State rate to the Treasury bill rate. Under the prior version of § 1961,

a losing defendant may have an economic incentive to appeal a judgment solely in order to retain his money and accumulate interest on it at the commercial rate during the pendency of the appeal.

S.Rep. No. 97275, supra, at 30. Because the prevailing state-set rates were significantly lower than market rates, losing parties found it economical to pursue frivolous appeals. Implicit in Congress' desire to alter the incentives to appeal is the understanding that, at the time judgment is entered, the parties are capable of calculating the value or cost of the interest throughout the time period during which the judgment remains unpaid. In other words, on the date of judgment, expectations with respect to interest liability were fixed, so that the parties could make informed decisions about the cost and potential benefits of paying the judgment or seeking appeal. Given Congress' understanding of the expectation of the parties on the date of judgment and the plain language of the statute, we conclude that both versions of § 1961 fix the rate of interest as of the date of the entry of judgment and, therefore, amended § 1961 may not be applied retrospectively. See 865 F.2d at 577 (Stapleton, J., concurring and dissenting) ("[T]he rule established by § 1961 after its amendment, as well as the rule established by it before, are focused on a particular point in time -the date of the entry of judgment. On that date, under both rules, the rate of postjudgment interest is fixed once and for all time for the particular case, and the rate fixed takes effect immediately").

Because the entry of judgment in this case occurred before October 1, 1982, we reverse the Court of Appeals' determination that amended § 1961 governs the calculation of postjudgment interest.

IV

Finally, in its cross-petition, Bonjorno asserts that the equities of the case require that the rate of interest be set at a rate higher than that afforded by § 1961. "At common law, judgments do not bear interest; interest rests solely upon statutory provision." Pierce v. United States, 255 U. S. 398, 255 U. S. 406 (1921). Where Congress has not seen fit to provide for a higher rate of interest with respect to antitrust suits and has set a definite interest rate that governs this case, the courts may not legislate to the contrary.

For the foregoing reasons, the judgment of the Court of Appeals is reversed in part and affirmed in part and the cases are remanded for further proceedings consistent with this opinion.

It is so ordered.