Insider trading law in the United States differs significantly both in design and scope from insider trading law in Australia. Whereas Australian law embodies a statute that explicitly prohibits securities trading while in possession of material nonpublic information, the US’s prohibition arises under the broad antifraud provisions in the federal securities laws, as interpreted by the US Supreme Court in a series of well-known decisions. Australian insider trading law also encompasses a broader prohibition because it operates on an “information connection” rather than a “person connection” – meaning that individuals who possess information that they know, or ought reasonably to know, is both material and nonpublic are prohibited from trading or from passing the information to others who might trade. In the United States, however, securities trading or tipping while in possession of material nonpublic information is illegal only insofar as it constitutes a fraud – meaning that the trader or tipper must breach a fiduciary duty of disclosure that is owed either to the securities issuer’s shareholders or to the source of the information. An American who finds in an airplane seatback a confidential corporate memo detailing a scientific development is not prohibited under US law from purchasing stock in the breakthrough company because he lacks the fiduciary connection that would render his silence in the securities transaction deceptive. But an Australian happening upon this same information and using it for personal trading profits would be violating Australia’s express statutory prohibition, whether or not the failure to disclose facts material to the transaction also constitutes a fraud.