When a takeover is announced, the sum of the stock-market values of the firms involved often falls, and the value of the acquirer almost always does. Does this mean that takeovers do not raise the values of the firms involved? Not necessarily. We set up a model in which the equilibrium number of...

Since 1968, the ratio of stock market capitalization to GDP has varied by a factor of 5. In 1972, the ratio stood at above unity, but by 1974, it had fallen to 0.45 where it stayed for the next decade. It then began a steady climb, and today it stands above 2. We argue that the IT revolution was...

This paper extends Lucas (1978) to a production economy with two capital goods. It is an RBC model in which each unit of investment requires a new idea, an "option". When options are scarce, new capital is harder to put in place and the value of old capital rises. Thus the stock market and...

In a model with multiple Pareto-ranked equilibria we add trade in assets that pay based on the realization of a sunspot. Asset trading restricts the equilibrium set in a way that raises welfare by eliminating equilibria with a high likelihood of disasters. When the probability of a disaster is...

Our paper reports the following two findings: 1) In monthly data, bond purchases by the Fed raise bond prices and reduce bond yields. The residual bond-supply to traders is not fully predictable, and this supply-risk adds between 10 and 40 basis points to the standard deviation of the real...

We study 114 years of U.S. stock market data and find That there are large cohort effects in stock prices, effects that we label 'organization capital,' That cohort effects grew at a rate of 1.75% per year, That the debt-equity ratio of all vintages declined, That three big technological waves...

Firms that entered the stock market in the 1990s were younger than any earlier cohort since World War I. Surprisingly, however, firms that IPO'd at the close of the 19th century were just as young as the companies that are entering today. We argue here that the electrification-era and the IT-era...

A satisfactory account of the postwar growth experience of the United States should be able to come to terms with the following three facts: 1. Since the early 1970's there has been a slump in the advance of productivity. 2. The price of new equipment has fallen steadily over the postwar period....

If machines are indivisible, a vintage capital model must give rise to income inequality. If new machines are always better than old ones and if society cannot provide everyone with a new machine all of the time, inequality will result. I explore this mechanism in detail. If technology resides...