I am one of those who have posted on the 400 share trades. I have not seen your list but I have heard of signals between MM's using price. The one thing I do know is that no one is going to place a 400 share order at the bell everyday with a retail value of only $100. I strongly believe all of the small lot trades are MM's keeping the appearance of liquidity (which is a good thing for us). As for the EOD 400 share trades, I don't know if they are a specific signal or just an effort to keep the price up. My guess is the latter since the past weeks have been heavy on the sell side with a pop EOD to mask it. The past few days however seem to be masked buying.