This robbed markets of a big slug of liquidity, almost certainly exacerbating the price falls.Another factor was the sudden retreat by the "high frequency" firms whose algorithmic trading has come to dominate equity markets.
For instance, we can say with a high degree of confidence that a particular market order was placed by a high-frequency firm, but do not point to whether the high-frequency trader in question was, for example, employed by Getco or Virtu.
He wants compulsory registration of high-frequency firms and pre-trade testing of their algorithms.
Brazil has been steadily making its systems more hospitable to high-frequency firms.
There are enough high-frequency firms that big orders can now be filled quickly and at lower costs.
Critics suspect some high-frequency firms of "quote stuffing," or firing off and immediately canceling thousands of orders each second to deliberately clog an exchange.
The committee, for example, found no evidence that high-frequency firms have been able to manipulate the prices of shares for their own benefit.
In August 2012 Knight Capital, a leading high-frequency-trading firm, collapsed in just hours after a new algorithm loaded into its system went rogue, causing losses of $440m at frightening speed.The main losers will be the traders in sweat-stained shirtsWhen measured by profits and the share of total trading undertaken by high-frequency firms, algorithmic trading also seems to be in decline.
REUTERS BREAKINGVIEWS High-Frequency Firms Said to Be in Merger Talks | RGM Advisors and Allston Trading, two of the large high-frequency trading firms in the United States, "have discussed a deal that would combine their respective strengths in automated stock trading and futures markets, according to people close to the talks," The Wall Street Journal reports.
The commodities agency and the Securities and Exchange Commission investigated the curious drop, ultimately concluding that high-frequency firms did not incite the so-called flash crash, although some did accelerate the free-fall.
To get the advantages that come with being listed as market makers, high-frequency firms were required to usually have offers posted to buy and sell the stocks in which they made markets.
