We model the relationship between asset float (tradeable shares) and speculative bubbles. Investors trade a stock with limited float because of insider lock-ups. They have heterogeneous beliefs due to overconfidence and face short-sales constraints. A bubble arises as price overweighs optimists'...

The U.S. went through a remarkable structural transformation between 1800 and 2000. In 1800 the majority of people worked in agriculture. Barely anyone did by 2000. What caused the rapid demise of agriculture in the economy? The analysis here concentrates on the development of new consumer goods...

We propose a framework for understanding recurrent historical episodes of vigorous economic expansion accompanied by extreme asset valuations, as exhibited by the U.S. in the 1990s. We interpret this phenomenon as a high-valuation equilibrium with a low effective cost of capital based on...

Together with a sense of entering a New Economy, the US experienced in the second half of the 1990s an economic expansion, a stock market boom, a financing boom for new firms and productivity gains. In this paper, we propose an interpretation of these events within a general equilibrium model...

During the Second Industrial Revolution, 1860-1900, many new technologies, including electricity, were invented. These inventions launched a transition to a new economy, a period of about 70 years of ongoing, rapid technical change. After this revolution began, however, several decades passed...

We review the evidence that artificial intelligence (AI) is having a large effect on the economy. Across a variety of statistics--including robotics shipments, AI startups, and patent counts--there is evidence of a large increase in AI-related activity. We also review recent research in this...

Private Investments in Public Equity (PIPEs) have become an important source of financing for young, publicly traded firms whose poor operating performance may limit alternative financing options. We propose that firms are motivated to sell these securities to minimize costs associated with...

Managers of private entrepreneurial firms face obstacles in raising capital both in placing a value on a firm and conveying value to investors. These problems are exacerbated when the firm is small, has limited assets (except for human capital) and has yet to have a lead product. In such cases...