Nanex ~ 19-May-2013 ~ BATS System Issue at Open
At the open of trading on May 19, 2013, BATS system appeared to have issues in a few
stocks. SPY was one of them. Fortunately, it looks like BATS found and corrected the
problem right away. Which is how it should be. Maybe BATS is a Better Alternative Trading
Here's an alert they put out shortly after we noticed the problem:
Charts below compare quote spread and trades from BATS with other exchanges in SPY.