Is the Internet Bubble Consistent with Rationality?

Abstract

Possibly. We empirically examine the plausibility of rational models designed to explain stock price bubbles associated with technological revolutions such as the internet. Our innovation is to examine the volatility patterns of old economy (brick and mortar) firms that adopted the internet as a medium of commerce (e-Commerce). During the bubble, there is an increase in idiosyncratic risk for firms adopting the technology while post-crash, there is an increase in systematic risk for the same technology adoption by firms both in the stock and options markets. We find some quantitative evidence that the weight of the e-Commerce business to justify the median firm's volatility increase in the bubble period, is borne out five years later with the actual sales data. Overall we conclude that our evidence is consistent with rationality and that both rational and behavioral approaches must provide quantitative predictions in order to have a sharper face off and to better understand asset price bubbles.