Tinkering with Ticks : Choosing Minimum Price Variation for US Equity Markets (1996 Version)

For two decades, researchers and practitioners alike have argued that constraining stock prices to eights of a dollar is unnecessarily restrictive. It has repeatedly been suggested that a smaller tick size would narrow bid-ask spreads and increase volume, and that in lower priced stocks the improvement in liquidity would be substantial. These arguments have recently gained both credence and popularity because of rigorous research work (Harris (1991, 1994)), and regulatory endorsement (SEC Market 2000 Report (1994)). However, a natural experiment using a recent change in tick size on the AMEX (from eights to sixteenths) finds little if any benefit to a smaller tick size in low priced stocks. Pervasive clustering of quotes and trades means that, in effect, market participants simply move from trading on eighths to trading on even sixteenths