One theory on the late-day slump in risk assets is a fake CPI report that's doing the rounds. It's a mock of up of a screenshot of the real report but it's filled with inaccuracies, typos and other issues.
Does that mean people are smart enough not to trade off it? I doubt it.
Update: An official from the US Labor Department is now out on the newswires confirming that the leak is fake and noting that it's circulating online.