The regulatory debate concerning high-frequency trading (HFT) emphasizes the importance of distinguishing different HFT strategies and their influence on market quality. Using data from NASDAQ-OMX Stockholm, we compare market-making HFTs to opportunistic HFTs. We find that market makers...

This is the internet appendix for "How Aggressive are High-Frequency Traders". The paper "How Aggressive are High-Frequency Traders" to which these Appendices apply is available at the following URL: "http://ssrn.com/abstract=2326446" http://ssrn.com/abstract=2326446

We study order aggressiveness of market-making high-frequency traders (HFTs), opportunistic HFTs, and non-HFTs. We find that market-making HFTs follow their own group's previous order submissions more than they follow other traders' orders. Opportunistic HFTs and non-HFTs tend to split market...

We exploit an optional colocation upgrade at NASDAQ OMX Stockholm to assess how speed affects market liquidity. Liquidity improves for the overall market and even for noncolocated trading entities. We find that the upgrade is pursued mainly by participants who engage in market making. Those that...

We study performance and competition among high-frequency traders (HFTs). We construct measures of latency and find that differences in relative latency account for large differences in HFTs' trading performance. HFTs that improve their latency rank due to colocation upgrades see improved...