Brown Shoe Co. v. United States

delivered the opinion of the Court.

I.

This suit was initiated in November 1955 when the Government filed a civil action in the United States District Court for the Eastern District of Missouri alleging that a contemplated merger between the G. R. Kinney Company, Inc. (Kinney), and the Brown Shoe Company, Inc. (Brown), through an exchange of Kinney for Brown stock, would violate § 7 of the Clayton Act, 15 U. S. C. § 18. The Act, as amended, provides in pertinent part:

“No corporation engaged in commerce shall acquire, directly or indirectly, the whole or any part of the stock or other share capital ... of another corporation engaged also in commerce, where in any line of commerce in any section of the country, the effect of such acquisition may be substantially to lessen competition, or to tend to create a monopoly.”

The complaint sought injunctive relief under § 15 of the Clayton Act, 15 U. S. C. § 25, to restrain consummation of the merger.

A motion by the Government for a preliminary injunction pendente lite was denied, and the companies were permitted to merge provided, however, that their businesses be operated separately and that their assets be kept separately identifiable. The merger was then effected on May 1, 1956.

*297In the District Court, the Government contended that the effect of the merger of Brown — the third largest seller of shoes by dollar volume in the United States, a leading manufacturer of men’s, women’s, and children’s shoes, and a retailer with over 1,230 owned, operated or controlled retail outlets1 — and Kinney — the eighth largest company, by dollar volume, among those primarily engaged in selling shoes, itself a large manufacturer of shoes, and a retailer with over 350 retail outlets — “may be substantially to lessen competition or to tend to create a monopoly” by eliminating actual or potential competition in the production of shoes for the national wholesale shoe market and in the sale of shoes at retail in the Nation, by foreclosing competition from “a market represented by Kinney’s retail outlets whose annual sales exceed $42,000,000,” and by enhancing Brown’s competitive advantage over other producers, distributors and sellers of shoes. The Government argued that the “line of commerce” affected by this merger is “footwear,” or alternatively, that the “line[s]” are “men’s,” “women’s,” and “children’s” shoes, separately considered, and that the “section of the country,” within which the anticompeti-tive effect of the merger is to be judged, is the Nation as a whole, or alternatively, each separate city or city and its *298immediate surrounding area in which the parties sell shoes at retail.

In the District Court, Brown contended that the merger would be shown not to endanger competition if the “line[s] of commerce” and the “section [s] of the country” were properly determined. Brown urged that not only were the age and sex of the intended customers to be considered in determining the relevant line of commerce, but that differences in grade of material, quality of workmanship, price, and customer use of shoes resulted in establishing different lines of commerce. While agreeing with the Government that, with regard to manufacturing, the relevant geographic market for assessing the effect of the merger upon competition is the country as a whole, Brown contended that with regard to retailing, the market must vary with economic reality from the central business district of a large city to a “standard metropolitan area” 2 for a smaller community. Brown further contended that, both at the manufacturing level and at the retail level, the shoe industry enjoyed healthy competition and that the vigor of this competition would not, in any event, be diminished by the proposed merger because Kinney manufactured less than 0.5% and retailed less than 2% of the Nation's shoes.

The District Court rejected the broadest contentions of both parties. The District Court found that “there is one group of classifications which is understood and recog*299nized by the entire industry and the public — the classification into 'men's/ ‘women's’ and ‘children’s’ shoes separately and independently.” On the other hand, “[t]o classify shoes as a whole could be unfair and unjust; to classify them further would be impractical, unwarranted and unrealistic.”

Realizing that “the areas of effective competition for retailing purposes cannot be fixed with mathematical precision,” the District Court found that “when determined by economic reality, for retailing, a ‘section of the country’ is a city of 10,000 or more population and its immediate and contiguous surrounding area, regardless of name designation, and in which a Kinney store and a Brown (operated, franchise, or plan) [3] store are located.”

The District Court rejected the Government’s contention that the combining of the manufacturing facilities of Brown and Kinney would substantially lessen competition in the production of men’s, women’s, or children’s shoes for the national wholesale market. However, the District Court did find that the likely foreclosure of other manufacturers from the market represented by Kinney’s retail outlets may substantially lessen competition in the manufacturers’ distribution of “men’s,” “women’s,” and “children’s” shoes, considered separately, throughout the Nation. The District Court also found that the merger may substantially lessen competition in retailing alone in “men’s,” “women’s,” and “children’s” shoes, considered separately, in every city of 10,000 or more population and its immediate surrounding area in which both a Kinney and a Brown store are located.

Brown’s contentions here differ only slightly from those made before the District Court. In order fully to understand and appraise these assertions, it is necessary to set *300out in some detail the District Court’s findings concerning the nature of the shoe industry and the place of Brown and Kinney within that industry.

The Industry.

The District Court found that although domestic shoe production was scattered among a large number of manufacturers, a small number of large companies occupied a commanding position. Thus, while the 24 largest manufacturers produced about 35% of the Nation’s shoes, the top 4 — -International, Endicott-Johnson, Brown (including Kinney) and General Shoe — alone produced approximately 23% of the Nation’s shoes or 65% of the production of the top 24.

In 1955, domestic production of nonrubber shoes was 509.2 million pairs, of which about 103.6 million pairs were men’s shoes, about 271 million pairs were women’s shoes, and about 134.6 million pairs were children’s shoes.4 The District Court found that men’s, women’s, and children’s shoes are normally produced in separate factories.

The public buys these shoes through about 70,000 retail outlets, only 22,000 of which, however, derive 50% or more of their gross receipts from the sale of shoes and are classified as “shoe stores” by the Census Bureau.5 These *30122,000 shoe stores were found generally to sell (1) men’s shoes only, (2) women’s shoes only, (3) women’s and children’s shoes, or (4) men’s, women’s, and children’s shoes.

The District Court found a “definite trend” among shoe manufacturers to acquire retail outlets. For example, International Shoe Company had no retail outlets in 1945, but by 1956 had acquired 130; General Shoe Company had only 80 retail outlets in 1945 but had 526 by 1956; Shoe Corporation of America, in the same period, increased its retail holdings from 301 to 842; Melville Shoe Company from 536 to 947; and Endicott-Johnson from 488 to 540. Brown, itself, with no retail outlets of its own prior to 1951, had acquired 845 such outlets by 1956. Moreover, between 1950 and 1956 nine independent shoe store chains, operating 1,114 retail shoe stores, were found to have become subsidiaries of these large firms and to have ceased their independent operations.

And once the manufacturers acquired retail outlets, the District Court found there was a “definite trend” for the parent-manufacturers to supply an ever increasing percentage of the retail outlets’ needs, thereby foreclosing other manufacturers from effectively competing for the retail accounts. Manufacturer-dominated stores were found to be “drying up” the available outlets for independent producers.

Another “definite trend” found to exist in the shoe industry was a decrease in the number of plants manufacturing shoes. And there appears to have been a concomitant decrease in the number of firms manufacturing shoes. In 1947, there were 1,077 independent manufacturers of shoes, but by 1954 their number had decreased about 10% to 970.6

*302 Broioji Shoe.

Brown Shoe was found not only to have been a participant, but also a moving factor, in these industry trends. Although Brown had experimented several times with operating its own retail outlets, by 1945 it had disposed of them all. However, in 1951, Brown again began to seek retail outlets by acquiring the Nation’s largest operator of leased shoe departments, Wohl Shoe Company (Wohl), which operated 250 shoe departments in department stores throughout the United States. Between 1952 and 1955 Brown made a number of smaller acquisitions: Wetherby-Kayser Shoe Company (three retail stores), Barnes & Company (two stores), Reilly Shoe Company (two leased shoe departments), Richardson Shoe Store (one store), and Wohl Shoe Company of Dallas (not connected with Wohl) (leased shoe departments in Dallas). In 1954, Brown made another major acquisition: Regal Shoe Corporation which, at the time, operated one manufacturing plant producing men’s shoes and 110 retail outlets.

The acquisition of these corporations was found to lead to increased sales by Brown to the acquired companies. Thus although prior to Brown’s acquisition of Wohl in 1951, Wohl bought from Brown only 12.8% of its total purchases of shoes, it subsequently increased its purchases to 21.4% in 1952 and to 32.6% in 1955. Wetherby-Kayser’s purchases from Brown increased from 10.4% before acquisition to over 50% after. Regal, which had previously sold no shoes to Wohl and shoes worth only $89,000 to Brown, in 1956 sold shoes worth $265,000 to Wohl and $744,000 to Brown.

During the same period of time, Brown also acquired the stock or assets of seven companies engaged solely in shoe manufacturing. As a result, in 1955, Brown was the *303fourth largest shoe manufacturer- in the country, producing about 25.6 million pairs of shoes or about 4% of the Nation’s total footwear production.

Kinney.

Kinney is principally engaged in operating the largest family-style shoe store chain in the United States. At the time of trial, Kinney was found to be operating over 400 such stores in more than 270 cities. These stores were found to make about 1.2% of all national retail shoe sales by dollar volume. Moreover, in 1955 the Kinney stores sold approximately 8 million pairs of nonrubber shoes or about 1.6% of the national pairage sales of such shoes. Of these sales, approximately 1.1 million pairs were of men’s shoes or about 1% of the national pairage sales of men’s shoes; approximately 4.2 million pairs were of women’s shoes or about 1.5% of the national pairage sales of women’s shoes; and approximately 2.7 million pairs were of children’s shoes or about 2% of the national pair-age sales of children’s shoes.7

In addition to this extensive retail activity, Kinney owned and operated four plants which manufactured men’s, women’s, and children’s shoes and whose combined output was 0.5% of the national shoe production in 1955, making Kinney the twelfth largest shoe manufacturer in the'United States.

Kinney stores were found to obtain about 20% of their shoes from Kinney’s own manufacturing plants. At the time of the merger, Kinney bought no shoes from Brown ; *304however, in line with Brown’s conceded reasons8 for acquiring Kinney, Brown had, by 1957, become the largest outside supplier of Kinney’s shoes, supplying 7.9% of all Kinney’s needs.

It is in this setting that the merger was considered and held to violate § 7 of the Clayton Act. The District Court ordered Brown to divest itself completely of all stock, share capital, assets or other interests it held in Kinney, to operate Kinney to the greatest degree possible as an independent concern pending complete divestiture, to refrain thereafter from acquiring or having any interest in Kinney’s business or assets, and to file with the court within 90 days a plan for carrying into effect the divestiture decreed. The District Court also stated it would retain jurisdiction over the cause to enable the parties to apply for such further relief as might be necessary to enforce and apply the judgment. Prior to its submission of a divestiture plan, Brown filed a notice of appeal in the District Court. It then filed a jurisdictional statement in this Court, seeking review of the judgment below as entered.

II.

Jurisdiction.

Appellant’s jurisdictional statement cites as the basis of our jurisdiction over this appeal § 2 of the Expediting *305Act of February 11, 1903, 32 Stat. 823, as amended, 15 U. S. C. § 29. In a civil antitrust action in which the United States is the complainant that Act provides for a direct appeal to this Court from “the final judgment of the district court.” 9 (Emphasis supplied.) The Government does not contest appellant’s claim of jurisdiction; on the contrary, it moved to have the judgment below summarily affirmed, conceding our present jurisdiction to review the merits of that judgment. We deferred ruling on the Government’s motion for summary affirmance and noted probable jurisdiction over the appeal. 363 U. S. 825.10

It was suggested from the bench during the oral argument that, since the judgment of the District Court does not include a specific plan for the dissolution of the Brown-Kinney merger, but reserves such a ruling pending the filing of suggested plans for implementing divestiture, the judgment below is not “final” as contemplated by the Expediting Act. In response to that suggestion, both parties have filed briefs contending that we do have jurisdiction to dispose of the case on the merits in its present posture. However, the mere consent of the parties to the Court’s consideration and decision of the case cannot, by itself, confer jurisdiction on the Court. See American Fire & Casualty Co. v. Finn, 341 U. S. 6, 17-18; People’s Bank v. Calhoun, 102 U. S. 256, 260-261; Capron v. Van Noorden, 2 Cranch 126, 127. Therefore, a review of the sources of the Court’s jurisdiction is a threshold *306inquiry appropriate to the disposition of every case that comes before us. Revised Rules of the Supreme Court, 15 (1) (b), 23 (1) (b); Kesler v. Department of Public Safety, 369 U. S. 153; Collins v. Miller, 252 U. S. 364; United States v. More, 3 Cranch 159.

The requirement that a final judgment shall have been entered in a case by a lower court before a right of appeal attaches has an ancient history in federal practice, first appearing in the Judiciary Act of 1789.11 With occasional modifications, the requirement has remained a cornerstone of the structure of appeals in the federal courts.12 The Court has adopted essentially practical tests for identifying those judgments which are, and those which are not, to be considered "final.” See, e. g., Cobble-dick v. United States, 309 U. S. 323, 326; Market Street R. Co. v. Railroad Comm’n, 324 U. S. 548, 552; Republic Natural Gas Co. v. Oklahoma, 334 U. S. 62, 69; Cohen v. Beneficial Industrial Loan Corp., 337 U. S. 541, 546; DiBella v. United States, 369 U. S. 121, 124, 129; cf. Federal Trade Comm’n v. Minneapolis-Honeywell Regulator Co., 344 U. S. 206, 212; United States v. Schaefer Brewing Co., 356 U. S. 227, 232. A pragmatic approach to the question of finality has been considered essential to the achievement of the “just, speedy, and inexpensive determination of every action”: 13 the touchstones of federal procedure.

In most cases in which the Expediting Act has been cited as the basis of this Court’s jurisdiction, the issue of “finality” has not been raised or discussed by the parties or the Court. On but few occasions have particular *307orders in suits to which that Act is applicable been considered in the light of claims that they were insufficiently “final” so as to preclude appeal to this Court.- Compare Schine Chain Theatres v. United States, 329 U. S. 686, with Schine Chain Theatres v. United States, 334 U. S. 110. The question has generally been passed over without comment in adjudications on the merits. While we are not bound by previous exercises of jurisdiction in cases in which our power to act was not questioned but was passed sub silentio, United States v. Tucker Truck Lines, 344 U. S. 33, 38; United States ex rel. Arant v. Lane, 245 U. S. 166, 170, neither should we disregard the implications of an exercise of judicial authority assumed to be proper for over 40 years.14 Cf. Stainback v. Mo *308Hock Ke Lok Po, 336 U. S. 368, 379-380; Radio Station WOW v. Johnson, 326 U. S. 120, 125-126.

We think the decree of the District Court in this case had sufficient indicia of finality for us to hold that the judgment is properly appealable at this time. We note, first, that the District Court disposed of the entire complaint filed by the Government. Every prayer for relief was passed upon. Full divestiture by Brown of Kinney’s stock and assets was expressly required. Appellant was permanently enjoined from acquiring or having any further interest in the business, stock or assets of the other defendant in the suit. The single provision of the judgment by which its finality may be questioned is the one requiring appellant to propose in the immediate future a plan for carrying into effect the court’s order of divestiture. However, when we reach the merits of, and affirm, the judgment below, the sole remaining task for the District Court will be its acceptance of a plan for full divestiture, and the supervision of the plan so accepted. Further rulings of the District Court in administering its decree, facilitated by the fact that the defendants below have been required to maintain separate books pendente lite, are sufficiently independent of, and subordinate to, the issues presented by this appeal to make the case in its present posture a proper one for review now.15 Appellant here does not attack the full divestiture ordered by the District Court as such; it is appellant’s contention that *309under the facts of the case, as alleged and proved by the Government, no order of divestiture could have been proper. The propriety of divestiture was considered below and is disputed here on an “all or nothing” basis. It is ripe for review now, and will, thereafter, be foreclosed. Repetitive judicial consideration of the same question in a single suit will not occur here. Cf. Radio Station WOW v. Johnson, supra, at 127; Catlin v. United States, 324 U. S. 229, 233-234; Cobbledick v. United States, supra, at 325, 330.

A second consideration supporting our view is the character of the decree still to be entered in this suit. It will be an order of full divestiture. Such an order requires careful, and often extended, negotiation and formulation. This process does not take place in a vacuum, but, rather, in a changing market place, in which buyers and bankers must be found to accomplish the order of forced sale. The unsettling influence of uncertainty as to the affirmance of the initial, underlying decision compelling divestiture would only make still more difficult the task of assuring expeditious enforcement of the antitrust laws. The delay in withholding review of any of the issues in the case until the details of a divestiture had been approved by the District Court and reviewed here could well mean a change in market conditions sufficiently pronounced to render impractical or otherwise unenforceable the very plan of asset disposition for which the litigation was held. The public interest, as well as that of the parties, would lose by such procedure.

Lastly, holding the decree of the District Court in the instant case less than “final” and, thus, not appealable, would require a departure from a settled course of the Court's practice. It has consistently reviewed antitrust decrees contemplating either future divestiture or other comparable remedial action prior to the formulation and *310entry of the precise details of the relief ordered. No instance has been found in which the Court has reviewed a case following a divestiture decree such as the one we are asked to consider here, in which the party subject to that decree has later brought the case back to this Court with claims of error in the details of the divestiture finally approved.16 And only two years ago, we were unanimous in accepting jurisdiction, and in affirming the judgment of a District Court similar to the one entered here, in the only case under amended § 7 of the Clayton Act brought before us at a juncture comparable to the instant litigation. See Maryland & Virginia Milk Producers Assn. v. United States, 362 U. S. 458, 472-473.17 A fear of piecemeal appeals because of our adherence to existing procedure can find no support in history. Thus, the substantial body *311of precedent for accepting jurisdiction over this case in its present posture supports the practical considerations previously discussed. We believe a contrary result would be inconsistent with the very purposes for which the Expediting Act was passed and that gave it its name.

HH l-H

Legislative History.

This case is one of the first to come before us in which the Government’s complaint is based upon allegations that the appellant has violated § 7 of the Clayton Act, as that section was amended in 1950.18 The amendments adopted in 1950 culminated extensive efforts over a number of years, on the parts of both the Federal Trade Commission and some members of Congress, to secure revision of a section of the antitrust laws considered by many observers to be ineffective in its then existing form. Sixteen bills to amend § 7 during the period 1943 to 1949 *312alone were introduced for consideration by the Congress, and full public hearings on proposed amendments were held in three separate sessions.19 In the light of this extensive legislative attention to the measure, and the broad, general language finally selected by Congress for the expression of its will, we think it appropriate to review the history of the amended Act in determining whether the judgment of the court below was consistent with the intent of the legislature. See United States v. E. I. du Pont de Nemours & Co., 353 U. S. 586, 591-592; Schwegmann Bros. v. Calvert Distillers Corp., 341 U. S. 384, 390-395; Federal Trade Comm’n v. Morton Salt Co., 334 U. S. 37, 43-46, 49; Corn Products Refining Co. v. Federal Trade Comm’n, 324 U. S. 726, 734-737.

As enacted in 1914, § 7 of the original Clayton Act prohibited the acquisition by one corporation of the stock of another corporation when such acquisition would result in a substantial lessening of competition between the acquiring and the acquired companies, or tend to *313create a monopoly in any line of commerce. The Act did not, by its explicit terms, or as construed by this Court, bar the acquisition by one corporation of the assets of another.20 Nor did it appear to preclude the acquisition of stock in any corporation other than a direct competitor.21 Although proponents of the 1950 amendments to the Act suggested that the terminology employed in these provisions was the result of accident or an unawareness that the acquisition of assets could be as inimical to competition as stock acquisition, a review of the legislative history of the original Clayton Act fails to support such views.22 The possibility of asset acquisition was discussed,23 but was not considered impor*314tant to an Act then conceived to be directed primarily at the development of holding companies and at the secret acquisition of competitors through the purchase of all or parts of such competitors’ stock.24

It was, however, not long before the Federal Trade Commission recognized deficiencies in the Act as first enacted. Its Annual Reports frequently suggested amendments, principally along two lines: first, to “plug the loophole” exempting asset acquisitions from coverage under the Act, and second, to require companies proposing a merger to give the Commission prior notification of their plans.25 The Final Report of the Temporary National Economic Committee also i ecommended changes focusing on these two proposals.26 Hearings were held on some bills incorporating either or both of these changes but, prior to the amendments adopted in 1950, none reached the floor of Congress for plenary consideration. Although the bill that was eventually to become amended § 7 was confined to embracing within the Act’s terms the *315acquisition of assets as well as stock, in the course of the hearings conducted in both the Eightieth and Eighty-first Congresses, a more far-reaching examination of the purposes and provisions of § 7 was undertaken. A review of the legislative history of these amendments provides no unmistakably clear indication of the precise standards the Congress wished the Federal Trade Commission and the courts to apply in judging the legality of particular mergers. However, sufficient expressions of a consistent point of view may be found in the hearings, committee reports of both the House and Senate and in floor debate to provide those charged with enforcing the Act with a usable frame of reference within which to evaluate any given merger.

The dominant theme pervading congressional consideration of the 1950 amendments was a fear of what was considered to be a rising tide of economic concentration in the American economy. Apprehension in this regard was bolstered by the publication in 1948 of the Federal Trade Commission’s study on corporate mergers. Statistics from this and other current studies were cited as evidence of the danger to the American economy in unchecked corporate expansions through mergers.27 Other considerations cited in support of the bill were the desir*316ability of retaining "local control” over industry and the protection of small businesses.28 Throughout the recorded discussion may be found examples of Congress’ fear not only of accelerated concentration of economic power on economic grounds, but also of the threat to other values a trend toward concentration was thought to pose.

What were some of the factors, relevant to a judgment as to the validity of a given merger, specifically discussed by Congress in redrafting § 7?

First, there is no doubt that Congress did wish to “plug the loophole” and to include within the coverage of the Act the acquisition of assets no less than the acquisition of stock.29

*317Second, by the deletion of the “acquiring-acquired” language in the original text,30 it hoped to make plain that § 7 applied not only to mergers between actual competitors, but also to vertical and conglomerate mergers whose effect may tend to lessen competition in any line of commerce in any section of the country.31

Third, it is apparent that a keystone in the erection of a barrier to what Congress saw was the rising tide of economic concentration, was its provision of authority for arresting mergers at a time when the trend to a lessening of competition in a line of commerce was still in its incip-iency. Congress saw the process of concentration in American business as a dynamic force; it sought to assure the Federal Trade Commission and the courts the power *318to brake this force at its outset and before it gathered momentum.32

Fourth, and closely related to the third, Congress rejected, as inappropriate to the problem it sought to remedy, the application to § 7 cases of the standards for judging the legality of business combinations adopted by the courts in dealing with cases arising under the Sherman Act, and which may have been applied to some early cases arising under original § 7.33

*319Fifth, at the same time that it sought to create an effective tool for preventing all mergers having demonstrable anticompetitive effects, Congress recognized the stimulation to competition that might flow from particular mergers. When concern as to the Act’s breadth was expressed, supporters of the amendments indicated that it would not impede, for example, a merger between two small companies to enable the combination to compete more effectively with larger corporations dominating the relevant market, nor a merger between a corporation which is financially healthy and a failing one which no longer can be a vital competitive factor in the market.34 *320The deletion of the word “community” in the original Act’s description of the relevant geographic market is another illustration of Congress’ desire to indicate that its concern was with the adverse effects of a given merger on competition only in an economically significant “section” of the country.35 Taken as a whole, the legislative history illuminates congressional concern with the protection of competition, not competitors, and its desire to restrain mergers only to the extent that such combinations may tend to lessen competition.

Sixth, Congress neither adopted nor rejected specifically any particular tests for measuring the relevant markets, either as defined in terms of product or in terms of geographic locus of competition, within which the anti-*321competitive effects of a merger were to be judged. Nor did it adopt a definition of the word “substantially,” whether in quantitative terms of sales or assets or market shares or in designated qualitative terms, by which a merger’s effects on competition were to be measured.36

Seventh, while providing no definite quantitative or qualitative tests by which enforcement agencies could gauge the effects of a given merger to determine whether it may “substantially” lessen competition or tend toward monopoly, Congress indicated plainly that a merger had to be functionally viewed, in the context of its particular *322industry.37 That is, whether the consolidation was to take place in an industry that was fragmented rather than concentrated, that had seen a recent trend toward domination by a few leaders or had remained fairly consistent in its distribution of market shares among the participating companies, that had experienced easy access to markets by suppliers and easy access to suppliers by buyers or had witnessed foreclosure of business, that had witnessed the ready entry of new competition or the erection of barriers to prospective entrants, all were aspects, varying in importance with the merger under consideration, which would properly be taken into account.38

*323Eighth, Congress used the words “may be substantially to lessen competition” (emphasis supplied), to indicate that its concern was with probabilities, not certainties.39 Statutes existed for dealing with clear-cut menaces to competition; no statute was sought for dealing with ephemeral possibilities. Mergers with a probable anticompetitive effect were to be proscribed by this Act.

It is against this background that we return to the case before us.

IV.

The Vertical Aspects of the Merger.

Economic arrangements between companies standing in a supplier-customer relationship are characterized as “vertical.” The primary vice of a vertical merger or other arrangement tying a customer to a supplier is that, *324by foreclosing the competitors of either party from a segment of the market otherwise open to them, the arrangement may act as a “clog on competition,” Standard Oil Co. of California v. United States, 337 U. S. 293, 314, which “deprive[s] . . . rivals of a fair opportunity to compete.” 40 H. R. Rep. No. 1191, 81st Cong., 1st Sess. 8. Every extended vertical arrangement by its very nature, for at least a time, denies to competitors of the supplier the opportunity to compete for part or all of the trade of the customer-party to the vertical arrangement. However, the Clayton Act does not render unlawful all such vertical arrangements, but forbids only those whose effect “may be substantially to lessen competition, or to tend to create a monopoly” “in any line of commerce in any section of the country.” Thus, as we have previously noted,

“[determination of the relevant market is a necessary predicate to a finding of a violation of the Clayton Act because the threatened monopoly must be one which will substantially lessen competition ‘within the area of effective competition.’ Substan-tiality can be determined only in terms of the market affected.” 41

The “area of effective competition” must be determined by reference to a product market (the “line of commerce”) and a geographic market (the “section of the country”).

*325 The Product Market.

The outer boundaries of a product market are determined by the reasonable interchangeability of use or the cross-elasticity of demand between the product itself and substitutes for it.42 However, within this broad market, well-defined submarkets may exist which, in themselves, constitute product markets for antitrust purposes. United States v. E. I. du Pont de Nemours & Co., 353 U. S. 586, 593-595. The boundaries of such a submarket may be determined by examining such practical indicia as industry or public recognition of the submarket as a separate economic entity, the product’s peculiar characteristics and uses, unique production facilities, distinct customers, distinct prices, sensitivity to price changes, and specialized vendors.43 Because § 7 of the Clayton Act prohibits any merger which may substantially lessen competition “in any line of commerce” (emphasis supplied), it is necessary to examine the effects of a merger in each such' economically significant submarket to determine if there is a reasonable probability that the merger will substantially lessen competition. If such a probability is found to exist, the merger is proscribed.44

*326Applying these considerations to the present case, we conclude that the record supports the District Court’s finding that the relevant lines of commerce are men’s, women’s, and children’s shoes. These product lines are recognized by the public; each line is manufactured in separate plants; each has characteristics peculiar to itself rendering it generally noncompetitive with the others; and each is, of course, directed toward a distinct class of customers.

Appellant, however, contends that the District Court’s definitions fail to recognize sufficiently “price/quality” and ''age/sex” distinctions in shoes. Brown argues that the predominantly medium-priced shoes which it manufactures occupy a product market different from the predominantly low-priced shoes which Kinney sells. But agreement with that argument would be equivalent to holding that medium-priced shoes do not compete with low-priced shoes. We think the District Court properly found the facts to be otherwise. It would be unrealistic to accept Brown’s contention that, for example, men’s shoes selling below $8.99 are in a different product market from those selling above $9.00.

This is not to say, however, that “price/quality” differences, where they exist, are unimportant in analyzing a merger; they may be of importance in determining the likely effect of a merger. But the boundaries of the relevant market must be drawn with sufficient breadth to include the competing products of each of the merging companies and to recognize competition where, in fact, competition exists. Thus we agree with the District Court that in this case a further division of product lines based on “price/quality” differences would be “unrealistic.”

*327Brown’s contention that the District Court’s product market definitions should have recognized further “age/sex” distinctions raises a different problem. Brown’s sharpest criticism is directed at the District Court’s finding that children’s shoes constituted a single line of commerce. Brown argues, for example, that “a little boy-does not wear a little girl’s black patent leather pump” and that “[a] male baby cannot wear a growing boy’s shoes.” Thus Brown argues that “infants’ and babies’ ” shoes, “misses’ and children’s” shoes and “youths’ and boys’ ” shoes should each have been considered a separate line of commerce. Assuming, arguendo, that little boys’ shoes, for example, do have sufficient peculiar characteristics to constitute one of the markets to be used in analyzing the effects of this merger, we do not think that in this case the District Court was required to employ finer “age/sex” distinctions than those recognized by its classifications of “men’s,” “women’s,” and “children’s” shoes. Further division does not aid us in analyzing the effects of this merger. Brown manufactures about the same percentage of the Nation’s children’s shoes (5.8%) as it does of the Nation’s youths’ and boys’ shoes (6.5%), of the Nation’s misses’ and children’s shoes (6.0%) and of the Nation’s infants’ and babies’ shoes (4.9 %). Similai ly, Kinney sells about the same percentage of the Nation’s children’s shoes (2%) as it does of the Nation’s youths’ and boys’ shoes (3.1%), of the Nation’s misses’ and children’s shoes (1.9%), and of the Nation’s infants’ and babies’ shoes (1.5%). Appellant can point to no advantage it would enjoy were finer divisions than those chosen by the District Court employed. Brown manufactures significant, comparable quantities of virtually every type of nonrubber men’s, women’s, and children’s shoes, and Kinney sells such quantities of virtually every type of men’s, women’s, and children’s shoes. Thus, whether considered separately or together, the picture 'of this *328merger is the same. We, therefore, agree with the District Court’s conclusion that in the setting of this case to subdivide the shoe market further on the basis of “age/sex” distinctions would be “impractical” and “unwarranted.”

The Geographic Market.

We agree with the parties and the District Court that insofar as the vertical aspect of this merger is concerned, the relevant geographic market is the entire Nation. The relationships of product value, bulk, weight and consumer demand enable manufacturers to distribute their shoes on a nationwide basis, as Brown and Kinney, in fact, do. The anticompetitive effects of the merger are to be measured within this range of distribution.

The Probable Effect of the Merger.

Once the area of effective competition affected by a vertical arrangement has been defined, an analysis must be made to determine if the effect of the arrangement “may be substantially to lessen competition, or to tend to create a monopoly” in this market.

Since the diminution of the vigor of competition which may stem from a vertical arrangement results primarily from a foreclosure of a share of the market otherwise open to competitors, an important consideration in determining whether the effect of a vertical arrang