This paper tests the hypothesis that the introduction of the Accelerated Cost Recovery System in 1981 caused a reduction in stock prices by reducing the value of existing capital. A second hypothesis that these depreciation changes benefited firms by increasing the return from new investment is also examined. Stock returns during the period surrounding enactment of this legislation are evaluated with data on capital stock and investment for over 800 firms. The empirical results suggest that neither hypothesis is an important determinant of cross-sectional differences in returns during this period. Differences in stock returns are in the direction predicted by the second hypothesis, but the relationship is not statistically significant. A test of the joint effects of both hypotheses operating simultaneously is supported by the data, but this relationship is also not statistically significant.
