The selling pressure was initially absorbed by intermediaries in the E-mini market, and in particular by High Frequency Traders (HFTs). HFTs are market participants that use high-speed, sophisticated computer algorithms to submit large numbers of trades on a daily basis. In general, HFTs do not hold their positions long enough to take directional bets. Instead, they participate on both sides of the market, maximizing turnover of their inventories in order to profit from the bid-ask spread. That is, they provide liquidity to the market, similar to traditional market makers.