How do insiders respond to regulatory oversight on the use of insider information? History suggests that they form more sophisticated networks to circumvent regulation. We develop a theory of the formation and regulation of insider information networks. We show that agents with sufficiently complex networks bypass any given regulatory environment. In response, regulators employ broad regulatory boundaries to combat gaming. Tighter regulation induces agents to migrate activity from existing social networks to a core-periphery insider network. A small group of agents endogenously arise as intermediaries for the bulk of transmissions.