Does Floor Trading Matter?

Abstract

While algorithmic trading now dominates financial markets, some exchanges continue to use human floor traders. On March 23, 2020 the NYSE suspended floor trading because of COVID-19. Using a difference-in-differences analysis, we find that floor traders are important contributors to market quality, even in the age of algorithmic trading. The suspension of floor trading leads to higher effective spreads, volatility, and pricing errors. Moreover, consistent with theoretical predictions about automation, the effects are strongest during and immediately following the opening auction when complexity is highest. Our findings suggest that human floor traders improve market quality.

Keywords: Algorithmic trading, DMM, human trading, floor trading, liquidity, market making, market quality, price efficiency

JEL Classification: G12, G14