At around the same time, because of the uncertainty surrounding the price collapse in the E-mini market, liquidity providers (traditional market makers and HFTs) withdrew from several individual equity markets and equity Exchange Traded Funds (ETFs) in order to assess the risk of continuing trading activity and the reliability of their data. This reaction caused liquidity to drop suddenly and prices to swing dramatically. In many markets, liquidity evaporated to the point that trades were executed at prices as low as a penny and as high as $100,000 (at the so-called “stub quotes,” quotes posted by market makers far away from current prices to fulfill their obligation to always quote a bid and ask price). As liquidity providers validated the integrity of their data and trading systems, they reentered the market. By approximately 3:00 p.m., securities that were severely disrupted during the crash converged back to their pre-crash levels.