"These are short-term bets. Very short. The founder of Tradebot, in Kansas City, Mo., told students in 2008 that his firm typically held stocks for 11 seconds. Tradebot, one of the biggest high-frequency traders around, had not had a losing day in four years, he said. "
This should not be happening. Arguments about liquidity are bunk (as I've explained many times on this blog) and this pattern of trading raises the cost of capital. Arbitraging my inability to own a supercomputer is abusive.