The biggest problem I've had with the trading patterns is the form t sales a few minutes after close.  Always at or below the lowest bid of the day, and usually a fairly large transaction.  That's where I see the most blatant manipulation going on.  I mean someone researching TECO for the first time in the evening or early morning sees that price from the previous day's trading and thinks, "Somebody knows something bad is about to happen, I think I'll pass."  Obviously form t trades are allowed, but the pattern for weeks was the same everyday.  I can't see who makes those trades, I don't have level II, but my guess is its the same culprit (mm) every time.