I was reading a paper written by one of Don Bright's traders about sub-pennying, where the trader talks about how when the market is hit, the direction of the move is likely to be against the trader who is hit on the whole penny. If this is the case (which I believe it to be), is it a sane and reasonable assumption to say that market makers in stocks on places like ARCA or NASDAQ generally almost always (well, let's say the probability p > .50, at the very least) absorb adverse-flow in the short run? Most passive entries will be against them, except in the occasional case where they get to the front and get some small random 100 lot or so? As an example, say BAC is (50,000 7.00 x 7.01 50,000), then a market maker at 7.01 who is first in queue gets hit at 7.01. If the trade is small, say 100 shares, maybe the odds are in his favor that the market won't go 7.01 x 7.02; however, if the trade is sizable against the book, it's going to go against him. Does this essentially mean that market makers are constantly in the business of taking short-term heat against them and managing that heat based on the assumption that the true price is in their favor in the longer term? Is it adequate to boil down the problem into something like: "You might be right in the next 5 milliseconds, but I will generally be right in the next 5 seconds?" Thoughts from the crowd?