shingle theory
Securities. The notion that a broker-dealer must be held to a high standard of conduct because by engaging in the securities business (“hanging out a shingle”), the broker-dealer implicitly represents to the world that the conduct of all its employees will be fair and meet professional norms. [Cases: Securities Regulation 27.21, 60.32(1). C.J.S. Securities Regulation §§ 76, 164, 195, 217.]