This document discusses US antitrust laws including the Sherman Antitrust Act of 1890 and the Clayton Act of 1914. It provides details on types of activities that are considered per se violations under Section 1 of the Sherman Act such as horizontal price fixing. It also discusses enforcement of these laws both within and outside the US, noting that US courts can apply antitrust laws extraterritorially if certain jurisdictional tests are met. These tests examine a defendant's contacts with the US and whether their conduct was intended to impact US commerce.