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

Employees are increasingly opting for defined contribution plans over defined benefit plans when given a choice. But this may not always be the best option. Using data from retirement plans available to employees of public educational institutions we show that, over the last fifty years,...

Firms added to (deleted from) the Samp;P 600 index experience a significant price increase(decrease) at announcement. Firms that newly enter (exit) the Samp;P universe experience a larger price increase (decrease) than firms that move between Samp;P indexes. Trading volumes are higher after the...