Illinois Tool Works Inc. v. Independent Ink, Inc., 547 U.S. 28 (2006), was a case decided by the Supreme Court of the United States involving the application of U.S. antitrust law to "tying" arrangements of patented products.

[1] The Court ruled unanimously[2] that there is not a presumption of market power under the Sherman Antitrust Act when the sale of a patented product is conditioned on the sale of a second product in a tying arrangement.

A plaintiff alleging an antitrust violation must instead establish the defendant's market power in the patented product through evidence.

Trident manufactured ink-related products used in printers used to print bar codes on cardboard.

In the course of a patent-infringement suit, Independent Ink alleged that Trident's license constituted a tying arrangement in violation of the Sherman Antitrust Act.