Investment of U.S. firms responds asymmetrically to Tobin's Q: investment of established firms -- 'intensive' investment -- reacts negatively to Q whereas investment of new firms -- 'extensive' investment -- responds positively and elastically to Q. This asymmetry, we argue, reflects a...

Growth of technological variety offers more scope for the division of labor. And when a division of labor requires some specific training, the technological specificity of human capital grows and, with it, probably the firm specificity of that capital. We build a simple model that captures this...

The rise in world trade since 1970 has raised international mobility of labor services. We study the effect of such a globalization of the world's labor markets. We find that when people can choose between wage work and managerial work, the output gains are U-shaped: A worldwide labor market...

We provide a model that links the high return to venture equity to the impatience of the VCs. VCs are scarce, and hence, they have market power and a high return on their investments. As a result, VCs are eager to terminate non-performing ventures so they can move on to new ones. The scarcity of...

We ask what level of migration would maximize world welfare. We find that skill-neutral policies are never optimal. An egalitarian welfare function induces a policy that entails moving mainly unskilled immigrants into the rich countries, whereas a welfare function skewed highly towards the rich...

Most industries go through a "shakeout" phase during which the number of producers in the industry declines. Industry output generally continues to rise, however, which implies a reallocation of capacity from exiting firms to incumbents and new entrants. Thus shakeouts seem to be classic...

Electricity and Information Technology (IT) are perhaps the two most important general purpose technologies (GPTs) to date. We analyze how the U.S. economy reacted to them. The Electricity and IT eras are similar, but also differ in several important ways. Electrification was more broadly...

Stock-market crashes tend to follow run-ups in prices. These episodes look like bubbles that gradually inflate and then suddenly burst. We show that such bubbles can form in a Zeira-Rob type of model in which demand size is uncertain. Two conditions are sufficient for this to happen: A declining...

We study the relation between IPO investment and the rate of interest. We model the IPO timing decision and show that the implied relation between interest rates and investment is non-monotonic, and the data support the implication. At low rates of interest firms delay their IPOs. This happens...

We argue that takeovers have played a major role in speeding up the diffusion of new technology. The role that they play is similar to that of entry and exit of firms. We focus on and compare two periods: 1890-1930 during which electricity and the internal combustion engine spread through the...