We analyze data provided by NASDAQ to examine how quote aggressiveness affects dealer market share and whether the practice of internalization mitigates the impact of quote aggressiveness. Our empirical results show that although internalization does not reduce the impact of price aggressiveness on dealer market share, it mitigates the impact of size aggressiveness. This result suggests that although internalization may not affect the dealer's incentive to post aggressive prices, it may reduce the incentive to post large depths. We find that aggressive quotes are more effective in raising dealer market share in stocks with a less competitive (more concentrated) market structure. Our results also show that the effective spread is wider (narrower) for stocks with a smaller price (size) elasticity of dealer market share.

Despite the widely held belief that order preferencing affects market quality, no hard evidence exists on the extent and determinants of order preferencing and its impact on dealer competition and execution quality. This study shows that the bid-ask spread (dealer quote aggressiveness) is positively (negatively) related to the proportion of internalized volume during both the pre- and post-decimalization periods. Although decimal pricing led to lower order preferencing on NASDAQ, the extent of order preferencing after decimalization is higher than what prior studies had predicted. The price impact of preferenced trades is smaller than that of unpreferenced trades and preferenced trades receive greater (smaller) size (price) improvements than unpreferenced trades.

Abstract This paper explores the competition between two trading venues, Electronic Communication Networks (ECNs) and Nasdaq market makers. ECNs offer the advantages of anonymity and speed of execution, which attract informed traders. Thus, trades are more likely to occur on ECNs when information asymmetry is greater and when trading volume and stock‐return volatility are high. ECN trades have greater permanent price impacts and more private information is revealed through ECN trades than though market‐maker trades. However, ECN trades have higher ex ante trading costs because market makers can preference or internalize the less informed trades and offer them better executions.