This paper examines unique data on dark pool activity for a large cross-section of US stocks in 2009. Dark pool activity is concentrated in liquid stocks. Nasdaq (AMEX) stocks have significantly higher (lower) dark pool activity than NYSE stocks controlling for liquidity. For a given stock, dark...

We show that when a continuous dark pool is added to a limit order book that opens illiquid, book and consolidated fill rates and volume increase, but spread widens, depth declines and welfare deteriorates. The adverse effects on market quality and welfare are mitigated when book-liquidity...

Trading venues often impose a minimum trade unit constraint (MTUC) to facilitate order execution. This paper examines the effects of a natural experiment at Borsa Italiana where the exchange reduced the MTUC to one share for all stocks. After the removal of the MTUC, we observe a substantial...

Reserve orders enable traders to hide a portion of their orders and now appear in most electronic limit order markets. This paper outlines a theory to determine an optimal submission strategy in a limit order book, in which traders choose among limit, market, and reserve orders and...

The U.S. equity markets recently increased the tick size from one to five cents for smaller capitalization stocks. We show that the larger tick size raised the cost for retail-sized liquidity demanding orders by almost fifty percent, and raised profits to liquidity providers by forty percent....