opinion: Mr. Justice Marshall
  delivered the opinion of the Court.
  The United States brought this action for injunctive relief against alleged violation by Topeo Associates, Inc. (Topeo), of § 1 of the Sherman Act, 26 Stat. 209, as amended, 15 U. S. C. § 1. Jurisdiction was grounded in § 4 of the Act, 15 U. S. C. § 4. Following a trial on the merits, the United States District Court for the Northern District of Illinois entered judgment for Topeo, 319 F. Supp. 1031, and the United States appealed directly to this Court pursuant to § 2 of the Expediting Act, 32 Stat. 823, as amended, 15 U. S. C. § 29. We noted probable jurisdiction, 402 U. S. 905 (1971), and we now reverse the judgment of the District Court.
  I
  Topeo is a cooperative association of approximately 25 small and medium-sized regional supermarket chains that operate stores in some 33 States. Each of the member chains operates independently; there is no pooling of earnings, profits, capital, management, or advertising resources. No grocery business is conducted under the Topeo name. Its basic function is to serve as a purchasing agent for its members. In this capacity, it procures and distributes to the members more than 1,000 different food and related nonfood items, most of which are distributed under brand names owned by Topeo. The association does not itself own any manufacturing, processing, or warehousing facilities, and the items that it procures for members are usually shipped directly from the packer or manufacturer to the members. Payment is made either to Topeo or directly to the manufacturer at a cost that is virtually the same for the members as for Topeo itself.
  All of the stock in Topeo is owned by the members, with the common stock, the only stock having voting rights, being equally distributed. The board of directors, which controls the operation of the association, is drawn from the members and is normally composed of high-ranking executive officers of member chains. It is the board that elects the association’s officers and appoints committee members, and it is from the board that the principal executive officers of Topeo must be drawn. Restrictions on the alienation of stock and the procedure for selecting all important officials of the association from within the ranks of its members give the members complete and unfettered control over the operations of the association.
  Topeo was founded in the 1940’s by a group of small, local grocery chains, independently owned and operated, that desired to cooperate to obtain high quality merchandise under private labels in order to compete more effectively with larger national and regional chains. With a line of canned, dairy, and other products, the association began. It added frozen foods in 1950, fresh produce in 1958, more general merchandise equipment and supplies in 1960, and a branded bacon and carcass beef selection program in 1966. By 1964, Topeo’s members had combined retail sales of more than $2 billion; by 1967, their sales totaled more than $2.3 billion, a figure exceeded by only three national grocery chains.
  Members of the association vary in the degree of market share that they possess in their respective areas. The range is from 1.5% to 16%, with the average being approximately 6%. While it is difficult to compare these figures with the market shares of larger regional and national chains because of the absence in the record of accurate statistics for these chains, there is much evidence in the record that Topeo members are frequently in as strong a competitive position in their respective areas as any other chain. The strength of this competitive position is due, in some measure, to the success of Topco-brand products. Although only 10% of the total goods sold by Topeo members bear the association’s brand names, the profit on these goods is substantial and their very existence has improved the competitive potential of Topeo members with respect to other large and powerful chains.
  It is apparent that from meager beginnings approximately a quarter of a century ago, Topeo has developed into a purchasing association wholly owned and operated by member chains, which possess much economic muscle, individually as well as cooperatively.
  II
  Section 1 of the Sherman Act provides, in relevant part:
  “Every contract, combination in the form of trust or otherwise, or conspiracy, in restraint of trade or commerce among the several States, or with foreign nations, is declared to be illegal . . .
  The United States charged that, beginning at least as early as 1960 and continuing up to the time that the complaint was filed, Topeo had combined and conspired with its members to violate § 1 in two respects. First, the Government alleged that there existed:
  “a continuing agreement, understanding and concert of action among the co-conspirator member firms acting through Topeo, the substantial terms of which have been and are that each co-conspirator member firm will sell Topco-controlled brands only within the marketing territory allocated to it, and will refrain from selling Topco-controlled brands outside such marketing territory.”
  The division of marketing territories to which the complaint refers consists of a number of practices by the association.
  Article IX, § 2, of the Topeo bylaws establishes three categories of territorial licenses that members may secure from the association:
  “(a) Exclusive — An exclusive territory is one in which the member is licensed to sell all products bearing specified trademarks of the Association, to the exclusion of all other persons.
  “(b) Non-exclusive — A non-exclusive territory is one in which a member is licensed to sell all products bearing specified trademarks of the Association, but not to the exclusion of others who may also be licensed to sell products bearing the same trademarks of the Association in the same territory.
  “(c) Coextensive — A coextensive territory is one in which two (2) or more members are licensed to sell all products bearing specified trademarks of the Association to the exclusion of all other persons. . .
  When applying for membership, a chain must designate the type of license that it desires. Membership must first be approved by the board of directors, and thereafter by an affirmative vote of 75% of the association’s members. If, however, the member whose operations are closest to those of the applicant, or any member whose operations are located within 100 miles of the applicant, votes against approval, an affirmative vote of 85%' of the members is required for approval. Bylaws, Art. I, § 5. Because, as indicated by the record, members cooperate in accommodating each other’s wishes, the procedure for approval provides, in essence, that members have a veto of sorts over actual or potential competition in the territorial areas in which they are concerned.
  Following approval, each new member signs an agreement with Topeo designating the territory in which that member may sell Topco-brand products. No member may sell these products outside the territory in which it is licensed. Most licenses are exclusive, and even those denominated “coextensive” or “non-exclusive” prove to be de facto exclusive. Exclusive territorial areas are often allocated to members who do no actual business in those areas on the theory that they may wish to expand at some indefinite future time and that expansion would likely be in the direction of the allocated territory. When combined with each member’s veto power over new members, provisions for exclusivity work effectively to insulate members from competition in Topco-brand goods. Should a member violate its license agreement and sell in areas other than those in which it is licensed, its membership can be terminated under Art. IV, §§ 2 (a) and 2 (b) of the bylaws. Once a territory is classified as exclusive, either formally or de facto, it is extremely unlikely that the classification will ever be changed. See Bylaws, Art. IX.
  The Government maintains that this scheme of dividing markets violates the Sherman Act because it operates to prohibit competition in Topco-brand products among grocery chains engaged in retail operations. The Government also makes a subsidiary challenge to Topco’s practices regarding licensing members to sell at wholesale. Under the bylaws, members are not permitted to sell any products supplied by the association at wholesale, whether trademarked or not, without first applying for and receiving special permission from the association to do so. Before permission is granted, other licensees (usually retailers), whose interests may potentially be affected by wholesale operations, are consulted as to their wishes in the matter. If permission is obtained, the member must agree to restrict the sale of Topeo products to a specific geographic area and to sell under any conditions imposed by the association. Permission to wholesale has often been sought by members, only to be denied by the association. The Government contends that this amounts not only to a territorial restriction violative of the Sherman Act, but also to a restriction on customers that in itself is vio-lative of the Act.
  Prom the inception of this lawsuit, Topeo accepted as true most of the Government’s allegations regarding territorial divisions and restrictions on wholesaling, although it differed greatly with the Government on the conclusions, both factual and legal, to be drawn from these facts.
  Topco’s answer to the complaint is illustrative of its posture in the District Court and before this Court:
  “Private label merchandising is a way of economic life in the food retailing industry, and exclusivity is the essence of a private label program; without exclusivity, a private label would not be private. Each national and large regional chain has its own exclusive private label products in addition to the nationally advertised brands which all chains sell. Each such chain relies upon the exclusivity of its own private label line to differentiate its private label products from those of its competitors and to attract and retain the repeat business and loyalty of consumers. Smaller retail grocery stores and chains are unable to compete effectively with the national and large regional chains without also offering their own exclusive private label products.
  “The only feasible method by which Topeo can procure private label products and assure the exclusivity thereof is through trademark licenses specifying the territory in which each member may sell such trademarked products.” Answer, App. 11.
  Topeo essentially maintains that it needs territorial divisions to compete with larger chains; that the association could not exist if the territorial divisions were anything but exclusive; and that by restricting competition in the sale of Topco-brand goods, the association actually increases competition by enabling its members to compete successfully with larger regional and national chains.
  The District Court, considering all these things relevant to its decision, agreed with Topeo. It recognized that the panoply of restraints that Topeo imposed on its members worked to prevent competition in Topco-brand products, but concluded that
  “[w]hatever anti-competitive effect these practices may have on competition in the sale of Topeo private label brands is far outweighed by the increased ability of Topeo members to compete both with the national chains and other supermarkets operating in their respective territories.” 319 F. Supp. 1031, 1043 (1970).
  The court held that Topco's practices were procompeti-tive and, therefore, consistent with the purposes of the antitrust laws. But we conclude that the District Court used an improper analysis in reaching its result.
  Ill
  On its face, § 1 of the Sherman Act appears to bar any combination of entrepreneurs so long as it is “in restraint of trade.” Theoretically, all manufacturers, distributors, merchants, sellers, and buyers could be considered as potential competitors of each other. Were § 1 to be read in the narrowest possible way, any commercial contract could be deemed to violate it. Chicago Board of Trade v. United States, 246 U. S. 231, 238 (1918) (Brandéis, J.). The history underlying the formulation of the antitrust laws led this Court to conclude, however, that Congress did not intend to prohibit all contracts, nor even all contracts that might in some insignificant degree or attenuated sense restrain trade or competition. In lieu of the narrowest possible reading of § 1, the Court adopted a “rule of reason” analysis for determining whether most business combinations or contracts violate the prohibitions of the Sherman Act. Standard Oil Co. v. United States, 221 U. S. 1 (1911). An analysis of the reasonableness of particular restraints includes consideration of the facts peculiar to the business in which the restraint is applied, the nature of the restraint and its effects, and the history of the restraint and the reasons for its adoption. Chicago Board of Trade v. United States, supra, at 238.
  While the Court has utilized the “rule of reason” in evaluating the legality of most restraints alleged to be violative of the Sherman Act, it has also developed the doctrine that certain business relationships are per se violations of the Act without regard to a consideration of their reasonableness. In Northern Pacific R. Co. v. United States, 356 U. S. 1, 5 (1958), Mr. Justice Black explained the appropriateness of, and the need for, per se rules:
  “[T]here are certain agreements or practices which because of their pernicious effect on competition and lack of any redeeming virtue are conclusively presumed to be unreasonable and therefore illegal without elaborate inquiry as to the precise harm they have caused or the business excuse for their use. This principle of per se unreasonableness not only makes the type of restraints which are proscribed by the Sherman Act more certain to the benefit of everyone concerned, but it also avoids the necessity for an incredibly complicated and prolonged economic investigation into the entire history of the industry involved, as well as related industries, in an effort to determine at large whether a particular restraint has been unreasonable — an inquiry so often wholly fruitless when undertaken.”
  It is only after considerable experience with certain business relationships that courts classify them as per se violations of the Sherman Act. See generally Van Cise, The Future of Per Se in Antitrust Law, 50 Va. L. Rev. 1165 (1964). One of the classic examples of a per se violation of § 1 is an agreement between competitors at the same level of the market structure to allocate territories in order to minimize competition. Such concerted action is usually termed a .“horizontal” restraint, in contradistinction to combinations of persons at different!' levels of the market structure, e. g,, manufacturers and I distributors, which are termed “vertical” restraints. This i¡ Court has reiterated time and time again that “[h]orizontal territorial limitations . . . are naked restraints off! trade with no purpose except stifling of competition .’’ White Motor Co. v. United States, 372 U. S. 253, 263 (1963). Such limitations are per se violations of the Sherman Act. See Addyston Pipe & Steel Co. v. United States, 175 U. S. 211 (1899), aff’g 85 F. 271 (CA6 1898) (Taft, J.); United States v. National Lead Co., 332 U. S. 319 (1947); Timken Roller Bearing Co. v. United States, 341 U. S. 593 (1951); Northern Pacific R. Co. v. United States, supra; Citizen Publishing Co. v. United States, 394 U. S. 131 (1969); United States v. Sealy, Inc., 388 U. S. 350 (1967); United States v. Arnold, Schwinn & Co., 388 U. S. 365, 390 (1967) (Stewart, J., concurring in part and dissenting in part); Serta Associates, Inc. v. United States, 393 U. S. 534 (1969), aff’g 296 F. Supp. 1121, 1128 (ND Ill. 1968).
  We think that it is clear that the restraint in this case is a horizontal one, and, therefore, a per se violation of § 1. The District Court failed to make any determination as to whether there were per se horizontal territorial restraints in this case and simply applied a rule of reason in reaching its conclusions that the restraints were not illegal. See, e. g., Comment, Horizontal Territorial Restraints and the Per Se Rule, 28 Wash. & Lee L. Rev. 457, 469 (1971). In so doing, the District Court erred.
  United States v. Sealy, Inc., supra, is, in fact, on all fours with this case. Sealy licensed manufacturers of mattresses and bedding to make and sell products using the Sealy trademark. Like Topeo, Sealy was a corporation owned almost entirely by its licensees, who elected the Board of Directors and controlled the business. Just as in this case, Sealy agreed with the licensees not to license other manufacturers or sellers to sell Sealy-brand products in a designated territory in exchange for the promise of the licensee who sold in that territory not to expand its sales beyond the area demarcated by Sealy. The Court held that this was a horizontal territorial restraint, which was per se violative of the Sherman Act.
  Whether or not we would decide this case the same way under the rule of reason used by the District Court is irrelevant to the issue before us. The fact is that courts are of limited utility in examining difficult economic problems. Our inability to weigh, in any meaningful sense, destruction of competition in one sector of the economy against promotion of competition in another sector is one important reason we have formulated per se rules.
  In applying these rigid rules, the Court has consistently rejected the notion that naked restraints of trade are to be tolerated because they are well intended or because they are allegedly developed to increase competition. E. g., United States v. General Motors Corp., 384 U. S. 127, 146-147 (1966); United States v. Masonite Corp., 316 U. S. 265 (1942); Fashion Originators’ Guild v. FTC, 312 U. S. 467 (1941).
  Antitrust laws in general, and the Sherman Act in particular, are the Magna Carta of free enterprise. They are as important to the preservation of economic freedom and our free-enterprise system as the Bill of Rights is to the protection of our fundamental personal freedoms. And the freedom guaranteed each and every business, no matter how small, is the freedom to compete— to assert with vigor, imagination, devotion, and ingenuity whatever economic muscle it can muster. Implicit in such freedom is the notion that it cannot be foreclosed with respect to one sector of the economy because certain private citizens or groups believe that such foreclosure might promote greater competition in a more important sector of the economy. Cf. United States v. Philadelphia National Bank, 374 U. S. 321, 371 (1963).
  The District Court determined that by limiting the freedom of its individual members to compete with each other, Topeo was doing a greater good by fostering competition between members and other large supermarket chains. But, the fallacy in this is that Topeo has no authority under the Sherman Act to determine the respective values of competition in various sectors of the economy. On the contrary, the Sherman Act gives to each Topeo member and to each prospective member the right to ascertain for itself whether or not competition with other supermarket chains is more desirable than competition in the sale of Topco-brand products. Without territorial restrictions, Topeo members may indeed: “[cut] each other’s throats.” Cf. White Motor Co., supra, at 278 (Clark, J., dissenting). But, we have never found this possibility sufficient to warrant condoning horizontal restraints of trade.
  The Court has previously noted with respect to price fixing, another per se violation of the Sherman Act, that:
  “The reasonable price fixed today may through economic and business changes become the unreasonable price of tomorrow. Once established, it may be maintained unchanged because of the absence of competition secured by the agreement for a price reasonable when fixed.” United States v. Trenton Potteries Co., 273 U. S. 392, 397 (1927).
  A similar observation can be made with regard to territorial limitations. White Motor Co., supra, at 265 n. 2 (Brennan, J., concurring).
  There have been tremendous departures from the notion of a free-enterprise system as it was originally conceived in this country. These departures have been the product of congressional action and the will of the people. If a decision is to be made to sacrifice competition in one portion of the economy for greater competition in another portion, this too is a decision that must be made by Congress and not by private forces or by the courts. Private forces are too keenly aware of their own interests in making such decisions and courts are ill-equipped and ill-situated for such decisionmaking. To analyze, interpret, and evaluate the myriad of competing interests and the endless data that would surely be brought to bear on such decisions, and to make the delicate judgment on the relative values to society of competitive areas of the economy, the judgment of the elected representatives of the people is required.
  Just as the territorial restrictions on retailing Topco-brand products must fall, so must the territorial restrictions on wholesaling. The considerations are the same, and the Sherman Act requires identical results.
  We also strike down Topco’s other restrictions on the right of its members to wholesale goods. These restrictions amount to regulation of the customers to whom members of Topeo may sell Topco-brand goods. Like territorial restrictions, limitations on customers are intended to limit intra-brand competition and to promote inter-brand competition. For the reasons previously discussed, the arena in which Topeo members compete must be left to their unfettered choice absent a contrary congressional determination. United States v. General Motors Corp., supra; cf. United States v. Arnold, Schwinn & Co., supra; United States v. Masonite Corp., supra; United States v. Trenton Potteries, supra. See also, White Motor Co., supra, at 281-283 (Clark, J., dissenting).
  We reverse the judgment of the District Court and remand the case for entry of an appropriate decree.
  It is so ordered.
  Mr. Justice Powell and Mr. Justice Rehnquist took no part in the consideration or decision of this case.
  Topeo, which is referred to at times in this opinion as the "association,” is actually composed of 23 chains of supermarket retailers and two retailer-owned cooperative wholesalers.
  In addition to purchasing various items for its members, Topeo performs other related functions: e. g., it insures that there is adequate quality control on the products that it purchases; it assists members in developing specifications on certain types of products (e. g., equipment and supplies); and it also aids the members in purchasing goods through other sources.
  The founding members of Topeo were having difficulty competing with larger chains. This difficulty was attributable in some degree to the fact that the larger chains were capable of developing their own private-label programs.
  Private-label products differ from other brand-name products in that they are sold at a limited number of easily ascertainable stores. A&P, for example, was a pioneer in developing a series of products that were sold under an A&P label and that were only available in A&P stores. It is obvious that by using private-label products, a chain can achieve significant cost economies in purchasing, transportation, warehousing, promotion, and advertising. These economies may afford the chain opportunities for offering private-label products at lower prices than other brand-name products. This, in turn, provides many advantages of which some of the more important are: a store can offer national-brand products at the same price as other stores, while simultaneously offering a desirable, lower priced alternative; or, if the profit margin is sufficiently high on private-brand goods, national-brand products may be sold at reduced price. Other advantages include: enabling a chain to bargain more favorably with national-brand manufacturers by creating a broader supply base of manufacturers, thereby decreasing dependence on a few, large national-brand manufacturers; enabling a chain to create a “price-mix” whereby prices on special items can be lowered to attract customers while profits are maintained on other items; and creation of general goodwill by offering lower priced, higher quality goods.
  The three largest chains are A&P, Safeway, and Kroger.
  Topeo was named in the complaint as the sole defendant, but the complaint clearly charged that its members, while not defendants, were coconspirators in Topco’s violation of the Sherman Act.
  Article IX, § 8, of the bylaws provides, in relevant part:
  “Unless a member’s membership and licensing agreement provides that such member may sell at wholesale, a member may not wholesale products supplied by the Association. If a membership and licensing agreement permits a member to sell at wholesale, such member shall control the resale of products bearing trademarks of the Association so that such sales are confined to the territories granted to the member, and the method of selling shall conform in all respects with the Association’s policies.”
  Shortly before trial, Topeo amended this bylaw with an addition that permitted any member to wholesale in the exclusive territories in which it retailed. But the restriction remained the same in all other cases.
  It is apparent that this bylaw on its face applies whether or not the products sold are trademarked by Topeo. Despite the fact that Topco’s general manager testified at trial that, in practice, the restriction is confined to Topco-branded products, the District Court found that the bylaw is applied as written. We find nothing clearly erroneous in this finding. Assuming, arguendo, however, that the restriction is confined to products trademarked by Topeo, the result in this ease would not change.
  When the Government first raised this point in the District Court, Topeo objected on the ground that it was at variance with the charge in the complaint. The District Court apparently agreed with Topeo that the complaint did not cover customer limitations, but permitted the Government to pursue this line on the basis that if the limitations were proved, the complaint could later be amended. App. 141. Topeo acquiesced in this procedure, and both sides dealt with customer limitations in examining witnesses. The District Court made specific findings and conclusions with respect to the totality of the restraints on wholesaling. In light of these facts, the additional fact that the complaint was never formally amended should not bar our consideration of the issue.
  The District Court recognized that “[t]he government has introduced evidence indicating that some applications by Topeo members to expand into territories assigned to other members have been denied,” 319 F. Supp. 1031, 1042, but concluded that these decisions by Topeo did not have an appreciable influence on the decision of members as to whether or not to expand. Topeo expands on this conclusion in its brief by asserting that “the evidence is uneontra-dicted that a member has never failed to build a new store because it was unable to obtain a license.” Brief for Appellee 18 n. 18. The problem with the conclusion of the District Court and the assertion by Topeo is that they are wholly inconsistent with the notion that territorial divisions are crucial to the existence of Topeo, as urged by the association and found by the District Court. From the filing of its answer to the argument before this Court, Topeo has maintained that without a guarantee of an exclusive territory, prospective licensees would not join Topeo and present licensees would leave the association. It is difficult to understand how Topeo can make this argument and simultaneously urge that territorial restrictions are an unimportant factor in the decision of a member on whether to expand its business.
  It is true that in Sealy the Court dealt with price fixing as well as territorial restrictions. To the extent that Sealy casts doubt on whether horizontal territorial limitations, unaccompanied by price fixing, are per se violations of the Sherman Act, we remove that doubt today.
  There has been much recent commentary on the wisdom of per se rules. See, e. g., Comment, Horizontal Territorial Restraints and the Per Se Rule, 28 Wash. & Lee L. Rev. 457 (1971); Averill, Sealy, Schwinn and Sherman One: An Analysis and Prognosis, 15 N. Y. L. F. 39 (1969); Note, Selected Antitrust Problems of the Franchisor: Exclusive Arrangements, Territorial Restrictions, and Franchise Termination, 22 U. Fla. L. Rev. 260, 286 (1969); Sadd, Antitrust Symposium: Territorial and Customer Restrictions After Sealy and Schwinn, 38 U. Cin. L. Rev. 249, 252-253 (1969); Bork, The Rule of Reason and the Per Se Concept, pt. 1, Price Fixing and Market Division, 74 Yale L. J. 775 (1965).
  Without the per se rules, businessmen would be left with little to aid them in predicting in any particular case what courts will find to be legal and illegal under the Sherman Act. Should Congress ultimately determine that predictability is unimportant in this area of the law, it can, of course, make -per se rules inapplicable in some or all cases, and leave courts free to ramble through the wilds of economic theory in order to maintain a flexible approach.