A wave of unusually heavy buying and selling roiled the stock market this morning, leading to a temporary halt in trading on numerous companies, after big names like Citigroup, Bank of America and American Airlines saw extreme swings in their prices. New Jersey based Knight Capital Group said that a "technology issue occurred" in the section of its business that uses computer algorithms to buy and sell stocks at high speed.

The sudden turmoil reminded many of the "Flash Crash" which occurred in May of 2010. "Stocks are moving all over the place, they are weird, they are trading like millions of shares, 100 shares at a time, so something went haywire somewhere," Stephen Massocca, managing director, Wedbush Morgan in San Francisco, told Reuters.

This morning the New York Stock Exchange was also introducing its Retail Liquidity Program, which was intended to compete with outfits like Knight Capital by giving retail investors access to so called "dark pools" of high speed trading that would allow them to find a better price. The NYSE says it will be investigating the irregular activity from this morning.