Well-defined submarkets may exist which, in themselves, constitute product markets for antitrust purposes.' Brown Shoe Co., 370 U.S. at 325, (1962); Cardinal Health, Inc., 12 F. Supp. 2d at 47 (concluding that 'the services provided by wholesalers in fact comprise a distinct submarket within the larger market of drug delivery.'); See e.g. Sysco, 113 F. Supp. 3d at 40 (holding that 'the ordinary factors that courts consider in defining a market-the Brown Shoe practical indicia and the Merger Guidelines' SSNIP test-support a finding that broadline distribution to national customers is a relevant product market.'); see also United States v. Phillipsburg Nat'l Bank & Trust Co., 399 U.S. 350, 360, 90 S. Ct. 2035, 26 L. Ed. 2d 658 (1970) ('[I]t is the cluster of products and services ... that as a matter of trade reality makes commercial banking a distinct' market).
Antitrust laws exist to protect competition, even for a targeted group that represents a relatively small part of an overall market.