We compare asset prices in an overlapping generations model for incomplete and complete markets. Individuals within a generational cohort have heterogeneous beliefs about future states of the economy and thus would like to make bets against each other. In the incomplete-markets economy,
agents cannot make such bets. Asset price volatility is very small. The situation changes dramatically when markets are completed through financial innovations as the set of available securities now allows agents with different beliefs to place bets against each other. Wealth shifts across
agents and generations. Such changes in the wealth distribution lead to substantial asset price volatility.
The American Economic Review is a general-interest economics journal. The journal is published quarterly and contains articles on a broad range of topics. Established in 1911, the AER is among the nation's oldest and most respected scholarly journals in the economics profession.