We adopt a power law framework to measure the concentration of daily trading among the different stocks on the US market. Our analysis of the trends of daily concentration over the last five decades reveals that trading concentration is lower on Mondays and the day after a long weekend. These...

We use the power law function to study changes in the distribution of trading volumes of S&P 500 stocks and non-S&P 500 stocks from 1960 to 2013. We find that the distribution of daily trading volumes has changed significantly for different baskets of non-index stocks and trading has become more...

We model the distribution of daily stock trading volume using the power law and document a new phenomenon. The power law exponent systematically increases with time suggesting that trading is becoming increasingly concentrated in a subset of stocks