This article considers the potential statistical problems resulting from the use of averaged rather than end-of-period data in financial research. Averaged data are widely employed throughout the literature without explicit recognition that the use of such data results in biased estimates of the...

This article provides a consistent monthly stock price index from January 1871 through 1999. The broadly defined Samp;P Weekly Index is reconstructed from 1918 and carried forward as the Samp;P 500 Composite Index to the present. Cowles's monthly index is improved in order to provide month-end...

We develop a simple measure of volatility based on extreme-day returns and apply it to market returns from 1885 to 2002. Because returns are not normally distributed, the extreme-day measure, which is distribution free, might provide a better measure of stock market risk than the traditional...