High Frequency Trading in the Equity Markets During U.S. Treasury POMO

We analyze high frequency trading (HFT) activity in equities during U.S. Treasury permanent open market (POMO) purchases by the Federal Reserve. We construct a model to study HFT quote and trade behavior when private information is released and confirm it empirically. We estimate that HFT firms reduce their inside quote participation by up to 8% during POMO auctions. HFT firms trade more aggressively, and they supply less passive liquidity to non-HFT firms. Market impact also rises during Treasury POMO. Aggressive HFT trading becomes more consistently profitable, and HFT firms earn a higher return per share. We also estimate that HFT firms earn profits of over $105 million during U.S. Treasury POMO events.