Changes in the Stock Price Reaction of Small Firms to Common Information

We hypothesize that changes in the technological and regulatory environment result in a more rapid response to marketwide information by small firms. We find that the correlations between small-firm returns and lagged large-firm returns decline over time, which suggests an increase in the efficiency of capital markets. Similar lead-lag patterns are found in the returns of portfolios sorted by dollar trading volume. The price response of low-volume stocks improves over time in much the same way as that of small-capitalization stocks.