The CEO of the New York Stock Exchange said today he thinks the SEC’s going to extend some kind of short selling protection to all publicy trade companies.

That’d be a biggie. It would mean, in some variety, that you can’t bet a stock’s going to go down.

Background: A couple of weeks ago the SEC decided to protect about two dozen financial firms from short sellers. The argument was that naysayers were doing damage to the larger markets by shorting, say, Lehman and Merrill Lynch. Ten days ago it expanded that list to more than 700 “financial” companies, “financial” being defined very loosely. Now, perhaps, all the companies on the Big Board. More to come, I’m sure.