Short-Circuiting the Markets

Among the many curious things about the emergency ban on short-selling in financial stocks is who's on the list.

Shares of financial firms like Fortress Investment Group and Goldman Sachs that run hedge funds that have certainly engaged in short selling at some point are on it. And some companies that have never before been identified as financials are on it.

Like I.B.M. Yes, Big Blue, the computing giant, is one of 12 stocks added to the New York Stock Exchange's list of do-not-short stocks today.

"I.B.M.'s a real head-scratcher," Bill King, chief market strategist at M. Ramsey King Securities, told the Wall Street Journal's MarketBeat blog. "There's no problem as far as we know with I.B.M. as far as financing or short interest or people pounding that."

The most famous short of the moment, meanwhile, David Einhorn, has come off the do-not-short list. Einhorn, who made headlines last spring by his questions about Lehman Brothers' balance sheet, is chairman of Greenlight Capital Re, a reinsurer based in the Cayman Islands that has come off Nasdaq's list.

If Einhorn is being true to his principles, then Man Group, the biggest publicly traded manager of a hedge fund, is not.

Of Man's $69 billion of assets, about 14 percent are invested in funds that both short and go long on stocks. Yet the company has reportedly asked British regulators that its shares be included in London's ban on short selling.

How big of them.