I think the MM's just have to provide the net amount of shares they sold (shares sold minus shares bought) by the end of the market day. For example, if they sold a net of 100,000 shares today and they did not actually have that 100,000 shares from previous days, they had to go out and buy them in the market before the market closed today. In a more extreme example, if they were to sell a net of 10 million shares in a day, they may find they cannot get 10 million shares by the close of the market. That would be very problematic for them. My guess is, however, they've been playing the market on this stock for long enough that they know about how many shares they can cover. Hopefully, though, that number has been going down over the last 40 days as people buy and hold their shares. That's the best remedy while we wait on NASDAQ, imho.