WOW, Protector not so fast. intraday always was, and likely for some of the big boys shorting still is
the MMs only have to "locate" shares in accounts that may be "available" for lending -- so who does the counting? Speculation, it would be the total of a broker's "in street held" irrespectively of what-ever the individual account holder might have decreed for his stock.
Now if at day close an MM could not cover, it used to be that they had several days extension (and past that shortfall around like musical chairs) -- supposed to now fixed?