Policy Documents

High Frequency Trading and Its Impact on Market Quality

Jonathan A. Brogaard –
September 20, 2010

This paper examines the impact of high frequency traders (HFTs) on the U.S. equity market. I analyze a unique data set to study the strategies utilized by HFTs, their profitability, and their relationship with characteristics of the overall market, including liquidity, price discovery, and volatility. The 26 high frequency trading (HFT) firms in my dataset participate in 74% of all trades and make up a larger percent of large market capitalization firms. I find the following key results: (1) HFTs tend to follow a price reversal strategy driven by order imbalances, (2) HFTs make approximately $3 billion annually, (3) HFTs do not seem to systematically front run non-HFTs, (4) HFTs rely on a less diverse set of strategies than do non-HFTs, (5) HFTs trading level changes only moderately as volatility increases, (6) HFTs add substantially to the price discovery process, (7) HFTs provide the best bid and offer quotes for a significant portion of the trading day, but only around one-fourth of the book depth as do non-HFTs, and (8) HFTs do not seem to increase volatility and may in fact reduce it.