Using 54 years of US quarterly data and a VAR model underpinned by a theory of the relationship between stock prices and output, this paper considers the deviations of
US stock prices from their fundamental value. To do this we derive the fundamental price-output ratio and the fundamental stock price under different assumptions regarding the time-variability of returns, and proceed to compare these to actual data.
Despite differences between model results, all imply cyclical deviations of actual values from values warranted by the expected growth in output - these deviations being relatively large since 1996.
