Quote from Thalamus09:
The market has always been at risk for this. Market Makers were supposedly the back stop before the electronic exchanges but they were always cowards too, and bailed when the bullets started flying. The only entity to provide a real backstop is the government and always will be. Who do you think purchased the market en mass at Dow -1,000 during the flash crash? It sure wasn't a non-government entity or private individuals. It was many of the large banks acting as surrogates for the Fed who has unlimited manipulation power, and the only entity with an "Other" column on their balance sheet that can hide the purchases.