Why do NASDAQ Market Makers Avoid Odd-Eighth Quotes?

Abstract

The NASDAQ multiple dealer market is designed to produce narrow bid-ask spreads through the competition for order flow among individual dealers. However, we find that odd-eighth quotes are virtually nonexistent for 70 of 100 actively traded NASDAQ securities, including Apple Computer and Lotus Development. The lack of odd-eighth quotes cannot be explained by the negotiation hypothesis ofHarris (1991), trading activity, or other variables thought to impact spreads. This result implies that the inside spread for a large number of NASDAQ stocks is at least $0.25 and raises the question of whether NASDAQ dealers implicitly collude to maintain wide spreads.