Flash trading, also known as high-frequency trading, is a practice where stock exchanges can wait up to one-half second before publishing bids and offers, giving customers of the specific exchange the opportunity to act before customers of other exchanges.http://www.bloomberg.com/apps/news?pid=20601087&sid=aO8DoToaITO8

The SEC was asked by Senator Charles Schumer to ban the practice in July of 2009, stating "this kind of unfair access seriously compromises the integrity of our markets and creates a two-tiered system, where a privileged group of insiders receives preferential treatment."http://www.bloomberg.com/apps/news?pid=20601087&sid=aO8DoToaITO8

However, the practice is still going on in 2010. The SEC is planing to require big traders to report their trades with brokerage firms so investors would get the information in real time.http://www.dailyfinance.com/story/investing/hidden-trading-sec-aims-to-shed-light-on-insidery-information/19440991/ The issue is that some traders are given preferential treatment. There is a promise that the option to flash trade could be given to all traders.</ref>http://blogs.forbes.com/davos/2010/05/22/dark-pools-the-menace-of-rising-opacity-in-financial-markets/