High Frequency Market Making to Large Institutional Trades

We study market-making high-frequency trader (HFT) dynamics around large institutional trades in Canadian equities markets using order-level data with masked trader identification. Following a regulatory change that negatively affected HFT order activity, we find that bid-ask spreads increased and price impact decreased for institutional trades. The decrease in price impact is strongest for informed institutional traders. During institutional trade executions, HFTs submit more same-direction orders and increase their inventory mean reversion rates. Our evidence indicates that high-frequency trading is associated with lower transaction costs for small, uninformed trades and higher transaction costs for large, informed trades