The SEC's suspension of short-selling expires at midnight.  Did it work?  Given that we cannot know what would have transpired without the ban, it is impossible to know.  I have to believe, though, that it's been a failure.  Short-sellers, for the most part, perform a valuable function.  Of course, it ihas been and continues to be appropriate to crack down on the fraction of short-selling that was/is predatory and fraudulent.  Ironically, a ban that was intended to stem the tide of selling, has actually washed away most of the interest in buying.  Hedge funds have a significant impact on the movement of markets—up and down.  An integral part of hedge fund strategy is to mitigate (i.e. hedge) risk by placing trades on the short side.  When it becomes more difficult to mitigate that risk, hedge funds are prudently uninterested in buying.  Net net, one of the largest sources of buying interest has been put on hold due to the suspension.  It is quite possible that some of the panic selling that's taken place over the past week or so could have been diminished if hedge funds and others would have had access to a necessary portfolio management tool—short selling.