With fixed costs of participating in the stock market, consumers with high income will participate in the stock market, but consumers with lower income will not participate. If a fully-funded defined-contribution social security system tries to exploit the equity premium by selling a dollar of...

In the presence of uncertain lifetimes, social security has the characteristics of an annuity: a consumer pays a tax when young in exchange for receiving a social security benefit if he survives to be old. If consumers have identical ex ante mortality probabilities, then a fully funded social...

The standard model of optimal growth, interpreted as a model of a market economy with infinitely long-lived agents, does not allow separation of the savings decisions of agents from the investment decisions of firms. Investment is essentially passive: the "one good" assumption leads to a...

For a firm that cannot raise external funds, cash on hand serves as precautionary saving. We derive a closed-form expression for the target level of cash on hand in the presence of persistent cash flows. Contrary to conventional wisdom, a mean-preserving increase in the volatility of cash flow...

Is the stock market boom a result of the baby boom? This paper develops an overlapping generations model in which a baby boom is modeled as a high realization of a random birth rate, and the price of capital is determined endogenously by a convex cost of adjustment. A baby boom increases...

Jim Poterba finds that consumers do not spend all of their assets during retirement, and he projects that the demand for assets will remain high when the baby boomers retire. Based on his forecast of continued high demand for capital, Poterba rejects the asset market meltdown hypothesis, which...