This article tests how demographic changes affect capital markets. The life-cycle investment hypothesis states that at an early stage an investor allocates more wealth in housing and then switches to financial assets at a later stage. Consequently, the stock market should rise but the housing market should decline with the average age, a prediction supported in the post-1945 period. The second hypothesis that an investor’s risk aversion increases with age is tested by estimating the resulting Euler equation and supported in the post 1945 period. A rise in average age is found to predict a rise in risk premiums. Journal ofBusiness, 1994,67(2): 165-202. (Reprinted with permission of the Journaf of Business.)