(1946) (emphasis added). “It is not necessary that the power thus obtained should be exercised. Its existence is sufficient.” Id. (internal quotation marks omitted).
The possession of monopoly power may be proven through direct or indirect evidence. Direct evidence of monopoly power is rare. “Where evidence indicates that a firm has in fact profitably” raised prices substantially above the competitive level, “the existence of monopoly power is clear.” Microsoft, 253 F.3d at 51. More often, courts “examine market structure in search of circumstantial evidence of monopoly power.” Id.; see id. at 57 (observing that “direct evidence [is not required] to show monopoly power in any market”). Under this indirect, structural approach, “monopoly power may be inferred from a firm’s possession of a dominant share of a relevant market that is protected by entry barriers.” Id. at 51.
A barrier to entry is “[a]ny market condition that makes entry more costly or time-consuming and thus reduces the effectiveness of potential competition as a constraint on the pricing behavior of the dominant firm . . . regardless of who is responsible for the existence of that condition.” S. Pac. Commc’ns Co. v. AT&T, 740 F.2d 980, 1001 (D.C. Cir. 1984). “Common entry barriers include: patents or other legal licenses, control of essential or superior resources, entrenched buyer preferences, high capital entry costs[,] and economies of scale.” Image Tech. Servs., Inc. v. Eastman Kodak Co., 125 F.3d 1195, 1208 (9th Cir. 1997); see also United States v. Syufy Enters., 903 F.2d 659, 667 (9th Cir. 1990) (observing that a “network of exclusive contracts or distribution arrangements designed to lock out potential competitors” is a barrier to entry). A plaintiff must not only show that such barriers to entry exist, but that those barriers are “significant[.]” Microsoft, 253 F.3d at 82.
Certain market behaviors are not inconsistent with a defendant’s possession of monopoly power. Evidence that a dominant firm invests in research and development is not antithetical to
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