Forthcoming in Econometrica 1This paper is dedicated to the memory of Gerard Debreu and Shizuo Kakutani. We are

We prove existence of equilibrium in a continuous-time securities market in which the securi-ties are potentially dynamically complete: the number of securities is at least one more than the number of independent sources of uncertainty. We prove that dynamic completeness of the candidate equilibrium price process follows from mild exogenous assumptions on the economic primitives of the model. Our result is universal, rather than generic: dynamic completeness of the candidate equilibrium price process and existence of equilibrium fol-low from the way information is revealed in a Brownian filtration, and of a mild exogenous nondegeneracy condition on the terminal security dividends. The nondegeneracy condition