JUSTICE POWELL delivered the opinion of the Court.
This case requires that we again consider the standard district courts must apply when deciding whether to grant summary judgment in an antitrust conspiracy case.
Stating the facts of this case is a daunting task. The opinion of the Court of Appeals for the Third Circuit runs to 69 pages; the primary opinion of the District Court is more than three times as long. In re Japanese Electronic Products Antitrust Litigation, 723 F.2d 238 (CA3 1983); 513 F. Supp. 1100 (ED Pa. 1981). Two respected District Judges each have authored a number of opinions in this case; the published ones alone would fill an entire volume of the Federal Supplement. In addition, the parties have filed a 40-volume appendix in this Court that is said to contain the essence of the evidence on which the District Court and the Court of Appeals based their respective decisions.
We will not repeat what these many opinions have stated and restated, or summarize the mass of documents that constitute the record on appeal. Since we review only the standard applied by the Court of Appeals in deciding this case, and not the weight assigned to particular pieces of evidence, we find it unnecessary to state the facts in great detail. What follows is a summary of this case’s long history.
Petitioners, defendants below, are 21 corporations that manufacture or sell “consumer electronic products” (CEPs) — for the most part, television sets. Petitioners include both Japanese manufacturers of CEPs and American firms, controlled by Japanese parents, that sell the Japanese-manufactured products. Respondents, plaintiffs below, are Zenith Radio Corporation (Zenith) and National Union Electric Corporation (NUE). Zenith is an American firm that manufactures and sells television sets. NUE is the corporate successor to Emerson Radio Company, an American firm that manufactured and sold television sets until 1970, when it withdrew from the market after sustaining substantial losses. Zenith and NUE began this lawsuit in 1974, claiming that petitioners had illegally conspired to drive American firms from the American CEP market. According to respondents, the gist of this conspiracy was a “`scheme to raise, fix and maintain artificially high prices for television receivers sold by [petitioners] in Japan and, at the same time, to fix and maintain low prices for television receivers exported to and sold in the United States.'” 723 F.2d, at 251 (quoting respondents’ preliminary pretrial memorandum). These “low prices” were allegedly at levels that produced substantial losses for petitioners. 513 F. Supp., at 1125. The conspiracy allegedly began as early as 1953, and according to respondents was in full operation by sometime in the late 1960’s. Respondents claimed that various portions of this scheme violated §§ 1 and 2 of the Sherman Act, § 2(a) of the Robinson-Patman Act, § 73 of the Wilson Tariff Act, and the Antidumping Act of 1916.
NUE had filed its complaint four years earlier, in the District Court for the District of New Jersey. Zenith’s complaint was filed separately in 1974, in the Eastern District of Pennsylvania. The two cases were consolidated in the Eastern District of Pennsylvania in 1974.
After several years of detailed discovery, petitioners filed motions for summary judgment on all claims against them. The District Court directed the parties to file, with preclusive effect, “Final Pretrial Statements” listing all the documentary evidence that would be offered if the case proceeded to trial. Respondents filed such a statement, and petitioners responded with a series of motions challenging the admissibility of respondents’ evidence. In three detailed opinions, the District Court found the bulk of the evidence on which Zenith and NUE relied inadmissible.
The inadmissible evidence included various government records and reports, Zenith Radio Corp. v. Matsushita Electric Industrial Co., 505 F. Supp. 1125 (ED Pa. 1980), business documents offered pursuant to various hearsay exceptions, Zenith Radio Corp. v. Matsushita Electric Industrial Co., 505 F. Supp. 1190 (ED Pa. 1980), and a large portion of the expert testimony that respondents proposed to introduce. Zenith Radio Corp. v. Matsushita Electric Industrial Co., 505 F. Supp. 1313 (ED Pa. 1981).
The District Court then turned to petitioners’ motions for summary judgment. In an opinion spanning 217 pages, the court found that the admissible evidence did not raise a genuine issue of material fact as to the existence of the alleged conspiracy. At bottom, the court found, respondents’ claims rested on the inferences that could be drawn from petitioners’ parallel conduct in the Japanese and American markets, and from the effects of that conduct on petitioners’ American competitors. 513 F. Supp., at 1125-1127. After reviewing the evidence both by category and in toto, the court found that any inference of conspiracy was unreasonable, because (i) some portions of the evidence suggested that petitioners conspired in ways that did not injure respondents, and (ii) the evidence that bore directly on the alleged price-cutting conspiracy did not rebut the more plausible inference that petitioners were cutting prices to compete in the American market and not to monopolize it. Summary judgment therefore was granted on respondents’ claims under § 1 of the Sherman Act and the Wilson Tariff Act. Because the Sherman Act § 2 claims, which alleged that petitioners had combined to monopolize the American CEP market, were functionally indistinguishable from the § 1 claims, the court dismissed them also. Finally, the court found that the Robinson-Patman Act claims depended on the same supposed conspiracy as the Sherman Act claims. Since the court had found no genuine issue of fact as to the conspiracy, it entered judgment in petitioners’ favor on those claims as well.
The District Court ruled separately that petitioners were entitled to summary judgment on respondents’ claims under the Antidumping Act of 1916. Zenith Radio Corp. v. Matsushita Electric Industrial Co., 494 F. Supp. 1190 (ED Pa. 1980). Respondents appealed this ruling, and the Court of Appeals reversed in a separate opinion issued the same day as the opinion concerning respondents’ other claims. In re Japanese Electronic Products Antitrust Litigation, 723 F.2d 319 (CA3 1983).
Petitioners ask us to review the Court of Appeals’ Antidumping Act decision along with its decision on the rest of this mammoth case. The Antidumping Act claims were not, however, mentioned in the questions presented in the petition for certiorari, and they have not been independently argued by the parties. See this Court’s Rule 21.1(a). We therefore decline the invitation to review the Court of Appeals’ decision on those claims.
The Court of Appeals for the Third Circuit reversed. The court began by examining the District Court’s evidentiary rulings, and determined that much of the evidence excluded by the District Court was in fact admissible. 723 F.2d, at 260-303. These evidentiary rulings are not before us. See 471 U.S. 1002 (1985) (limiting grant of certiorari).
As to 3 of the 24 defendants, the Court of Appeals affirmed the entry of summary judgment. Petitioners are the 21 defendants who remain in the case.
On the merits, and based on the newly enlarged record, the court found that the District Court’s summary judgment decision was improper. The court acknowledged that “there are legal limitations upon the inferences which may be drawn from circumstantial evidence,” 723 F.2d, at 304, but it found that “the legal problem . . . is different” when “there is direct evidence of concert of action.” Ibid. Here, the court concluded, “there is both direct evidence of certain kinds of concert of action and circumstantial evidence having some tendency to suggest that other kinds of concert of action may have occurred.” Id., at 304-305. Thus, the court reasoned, cases concerning the limitations on inferring conspiracy from ambiguous evidence were not dispositive. Id., at 305. Turning to the evidence, the court determined that a factfinder reasonably could draw the following conclusions: