The Impact of the Reduction in Tick Increments in Major U.S. Markets on Spreads, Depth, and Volatility.

This study presents an analysis of the impact of the introduction of quotes in sixteenths of a dollar on the AMEX, Nasdaq, and NYSE in mid-1997 on select market characteristics such as spreads, effective spreads, quoted depth, and volume. The findings of the study document reductions in the bid-ask spread, effective spread, and a statistically significant increase in the number of quotes. Interestingly, we find that liquidity, as measured by the total depth at the bid and ask, declines significantly on the AMEX and NYSE, but increases on the Nasdaq. Trading volume increases on the NYSE, but remains unchanged for the AMEX and Nasdaq. We also find that the proportion of even-increment quotes is a relevant factor affecting percentage spreads for Nasdaq both before and after and for the NYSE only after the change in quoting increments. Copyright 2000 by Kluwer Academic Publishers