High-frequency trading (HFT) is the use of sophisticated technological tools to trade securities like stocks or options, and is typically characterized by several distinguishing features
HFT is highly quantitative, employing computerized algorithms to analyze incoming market data and implement proprietary trading strategies;
HFT usually implies a firm holds an investment position only for very brief periods of time - even just seconds - and rapidly trades into and out of those positions, sometimes thousands or tens of thousands of times a day;
HFT firms typically end a trading day with no net investment position in the securities they trade;
HFT operations are usually found in proprietary firms or on proprietary trading desks in larger, diversified firms;
HFT strategies are usually very sensitive to the processing speed of markets and of their own access to the market.
In high-frequency trading, programs analyze market data to capture trading opportunities that may open up for only a fraction of a second to several hours.High-frequency trading (HFT) uses computer programs and sometimes specialised hardware to hold short-term positions in equities, options, futures, ETFs, currencies, and other financial instruments that possess electronic trading capability.[4] High-frequency traders compete on a basis of speed with other high-frequency traders, not long-term investors (who typically look for opportunities over a period of weeks, months, or years), and compete with each other for very small, consistent profits. As a result, high-frequency trading has been shown to have a potential Sharpe ratio (measure of reward per unit of risk) thousands of times higher than the traditional buy-and-hold strategies. By 2010 high-frequency trading accounted for over 70% of equity trades taking place in the US and was rapidly growing in popularity in Europe and Asia. Aiming to capture just a fraction of a penny per share or currency unit on every trade, high-frequency traders move in and out of such short-term positions several times each day. Fractions of a penny accumulate fast to produce significantly positive results at the end of every day. High-frequency trading firms do not employ significant leverage, do not accumulate positions, and typically liquidate their entire portfolios on a daily basis.
One financial industry source claims algorithmic trading, including high-frequency trading, substantially improves market liquidity.An academic study shows additional benefits, including lowering the costs of trading,increasing the informativeness of quotes,improved linkage between markets, and other positive spillover effects, at least in quiescent or stable markets; the authors of this study also note that "it remains an open question whether algorithmic trading and algorithmic liquidity supply are equally beneficial in more turbulent or declining markets...algorithmic liquidity suppliers may simply turn off their machines when markets spike downward."Also noteworthy is that HFT only takes place in markets that are already deemed liquid, hence calling its necessity into question.
Algorithmic and high-frequency trading were both implicated in the May 6, 2010 Flash Crash, when high-frequency liquidity providers were in fact found to have withdrawn from the market. A July, 2011 report by the International Organization of Securities Commissions (IOSCO), an international body of securities regulators, concluded that while "algorithms and HFT technology have been used by market participants to manage their trading and risk, their usage was also clearly a contributing factor in the flash crash event of May 6, 2010."
