Abstract
This article investigates insider information in the context of a standard continuous time financial market model. We derive necessary and sufficient conditions for the existence of arbitrage opportunities in terms of the insider's information flow. We prove that if the investment horizon of an insider ends after his initial information advantage has disappeared, an insider has arbitrage opportunities if and only if the anticipative information is non-atomic. For atomic anticipative information we identify how additional information affects the optimal trading strategy of an insider. We proof that the valuation of contingent claims measurable with respect to public information at maturity is invariant to insider information if the latter does not allow for arbitrage opportunities. In contrast contingent claims have zero value for insiders with anticipative information generated by non-atomic signals.

Abstract
The solutions of Rindisbacher (1998) for the individual consumption-investment problem of an insider are used to address questions about existence and informational nature of equilibrium in financial markets . First we show that if agents are ignorant about the possible asymmetries in the flows of information and their impact on equilibrium prices, a non-Markovian Walrasian eq uilibrium (NMWE) exists if and only if private signals which generate insider information are individually redundant. Market clearing conditions imply that the least informed investor can crucially determine which flow of information can be supported by e quilibrium. Consequently, better informed risk averse agents have always an incentive to enlarge the flow of information of less informed investors. We show that market clearing also implies that non-redundant information in equilibrium must be symmetric. It follows that in equilibrium an investor?s flow of information must be equivalent with an equilibrium in which ex ante investors communicate the ir private information to all participants in the market. By analogy to the equilibrium concepts introduced by Lucas (1972) and Green (1973) for Markovian models we call such an equilibrium, non-Markovian Green-Lucas equilibrium (NMGLE), which is a non-Ma rkovian equivalent of a rational expectations equilibrium. For this equilibrium we derive explicit expressions for equilibrium prices, their volatility and volumes of trade. We compare the implications of NMWE and NMGLE for the conditional version of the CCAPM. Since in both NMWE and NMGLE information asymmetries disappear we argue that heterogeneous information cannot serve as a potential explanation of the risk premium puzzle if the econometrician has the same information as the market participants.