delivered the opinion of the Court.
Frоm 1998 until 2002, petitioners Texaco Inc. and Shell Oil Co. collaborated in a joint venture, Equilon Enterprises, to refine and sell gasoline in the western United States under the original Texaco and Shell Oil brаnd names. Respondents, a class of Texaco and Shell Oil service station owners, allege that petitioners engaged in unlawful price fixing when Equilon set a single price for both Texaco and Shell Oil brand gasoline. We granted certiorari to determine whether it is per se illegal under § 1 of the Sherman Act, 15 U. S. C. § 1, for a lawful, economically integrated joint venture to set the prices at whiсh the joint venture sells its products. We conclude that it is not, and accordingly we reverse the contrary judgment of the Court of Appeals.
I
Historically, Texaco and Shell Oil have comрeted with one another in the national and international oil and gasoline *4 markets. Their business activities include refining crude oil into gasoline, as well as marketing gasoline to downstream purchasers, such as the service stations represented in respondents’ class action.
In 1998, Texaco and Shell Oil formed- a joint venture, Equilon, to consolidate their operations in thе western United States, thereby ending competition between the two companies in the domestic refining and marketing of gasoline. Under the joint venture agreement, Texaco and Shell Oil agreed to pool their resources and share the risks of and profits from Equilon’s activities. Equilon’s board of directors would comprise representatives of Texaco and Shell Oil, and Equilоn gasoline would be sold to downstream purchasers under the original Texaco and Shell Oil brand names. The formation of Equilon was approved by consent decree, subject to certain divestments and other modifications, by the Federal Trade Commission, see In re Shell Oil Co., 125 F. T. C. 769 (1998), as well as by the state attorneys general of California, Hawaii, Oregon, and Washington. Notably, the decrees imрosed no restrictions on the pricing of Equilon gasoline.
After the joint venture began to operate, respondents brought suit in District Court, alleging that, by unifying gasoline prices under the two brands, petitioners had violated the
per se
rule against price fixing that this Court has long recognized under § 1 of the Sherman Act, ch. 647, 26 Stat. 209, as amended, 15 U. S. C. § 1. See,
e. g., Catalano, Inc.
v.
Target Sales, Inc.,
II
Section 1 of the Sherman Act prohibits “[e]very contract, combination in the form of trust or otherwise, or conspiracy, in restraint of trade or commerce among the several States.” 15 U. S. C. § 1. This Court has not taken a literal approach to this language, however. See,
e. g., State Oil Co.
v.
Khan, 522
U. S. 3, 10 (1997) (“[T]his Court has long recognized that Congress intended to outlaw only
unreasonable
restraints” (emphаsis added)). Instead, this Court presumptively applies rule of reason analysis, under which antitrust plaintiffs must demonstrate that a particular contract or combination is in fact unreasonable and anticompetitive before it will be found unlawful. See,
e. g., id.,
at 10-19.
Per se
liability is reserved for only those agreements that are “so plainly anti-competitive that no elaborate study of the industry is needed to establish their illegality.”
National Soc. of Professional Engineers
v.
United States,
Price-fixing agreements between two or more competitors, otherwise known as horizontal price-fixing agreements, fall into the category of arrangements that are
per se
unlawful. See,
e. g., Catalano, supra,
at 647. Thеse cases do not present such an agreement, however, because Texaco and Shell Oil did not compete with one another in the relevant market — namely, the sale оf gasoline to service stations in the western United States — but instead participated in that
*6
market jointly through their investments in Equilon.
1
In other words, the pricing policy challenged here amounts to little more than price setting by a single entity — albeit within the context of a joint venture — and not a pricing agreement between competing entities with respect to their competing products. Throughout Equilon’s existencе, Texaco and Shell Oil shared in the profits of Equilon’s activities in their role as investors, not competitors. When “persons who would otherwise be competitors pool their capital and share the risks of loss as well as the opportunities for profit.. . such joint ventures [are] regarded as a single firm competing with other sellers in the market.”
Arizona
v.
Maricopa County Medical Soc.,
This conclusion is confirmed by respondents’ apparent concession that there would be no per se liability had Equilon simply chosen to sell its gasoline under a single brand. See Tr. of Oral Arg. 34. We see no reason to treat Equilon differently just because it chose to sell gasoline under two dis *7 tinct brands at a single price. As a single entity, a joint venture, like any other firm, must have the discretion to determine the рrices of the products that it sells, including the discretion to sell a product under two different brands at a single, unified price. If Equilon’s price unification policy is anticompetitive, then respondents should have challenged it pursuant to the rule of reason. 2 But it would be inconsistent with this Court’s antitrust precedents to condemn the internal pricing decisions of a legitimate joint venture as per se unlawful. 3
The court below reached the opposite conclusion by invoking the ancillary restraints doctrine.
“In this case, nothing more radical is afoot than the fact that an entity, which now owns all of the production, transportation, research, storage, sаles and distribution facilities for engaging in the gasoline business, also prices its own products. It decided to price them the same, as any other entity could. What could be more integral to the running of a business than setting a price for its goods and services?”369 F. 3d, at 1127 .
See also Broadcast Music, supra, at 23 (“Joint ventures and other cooperative arrangements are ... not usually unlawful, at least not as price-fixing schemes, whеre the agreement on price is necessary to market the product at all”).
* * *
Because the pricing decisions of a legitimate joint venture do not fall within the narrow categоry of activity that is per se unlawful under § 1 of the Sherman Act, respondents’ antitrust claim cannot prevail. Accordingly, the judgment of the Court of Appeals is reversed.
It is so ordered.
Notes
We presume for purposes of these cases that Equilon is a lawful joint venture. Its formation has been approved by federal and state regulators, and there is no contention here that it is a sham. As the court below noted: “There is a voluminous record documenting the economic justifications for creating the joint ventures. [T]he defendants concluded that numerous synergies and cost efficiencies would result” by creating Equilon as well as a parallel venture, Motiva Enterprises, in the eastern United States, and “that nationwide there would be up to $800 million in cost savings annually.”
Respondents have not put forth a rule of reason claim.
Respondents alternatively сontend that petitioners should be held liable under the quick look doctrine. To be sure, we have applied the quick look doctrine to business activities that are so plainly anticоmpetitive that courts need undertake only a cursory examination before imposing antitrust liability. See
California Dental Assn.
v.
FTC,
