Was there a NASDAQ bubble in the late 1990s

Not necessarily. The fundamental value of a firm increases with uncertainty about average future profitability, and this uncertainty was unusually high in the late 1990s. We calibrate a stock valuation model that includes this uncertainty, and compute the level of uncertainty that is needed to match the observed Nasdaq valuations at their peak. This uncertainty seems plausible because it matches not only the high level but also the high volatility of Nasdaq stock prices. We also show that uncertainty about average profitability has the biggest effect on stock prices when the equity premium is low