The finger-pointing has begun, and guess who is wearing the target? Short-sellers, of course.

If your response is, "Haven't we been down this road already?" the answer is yes. But it's a road regulators never seem to tire of traveling.

On Thursday, New York attorney general Andrew Cuomo launched an investigation into whether or not some short-sellers of financial stocks have been illegally spreading false rumors about the companies to precipitate their stock declines. The two biggest California pension funds also announced today they would stop lending out their shares in certain financial stocks to institutions for shorting.

This news comes just a day after Morgan Stanley chief executive John Mack phoned regulators to complain that short-sellers were destroying Morgan's shares.

In the U.K., regulators took a more drastic step. The Financial Services Authority banned short-selling of financial stocks for the rest of the year.

Here in the U.S., the Securities and Exchange Commission is also investigating rumors and contemplating whether or not to require hedge funds to disclose their short positions. (Update: Late Thursday, the S.E.C. joined the F.S.A. in instituting a ban on shorting financial shares.)

All this is a lot of piling on to a group that likely lost a bundle in the markets today. The Dow surged late in the trading session to close with a 410-point gain.

So far, there hasn't been any solid evidence that short-sellers are even to blame for this massive unwinding of these over-leveraged institutions. As Jesse Eisinger points out, short-sellers were not involved in the series of disastrous steps that A.I.G. took that ultimately led to its demise. The shorts may have benefited from those steps, sure, but they didn't have any part in encouraging A.I.G. to hop aboard the high-flying credit-default swaps ride.

Eisinger offers a potential solution for much of the problems in volatile markets like today's. In his column in the October issue of Condé Nast Portfolio, Eisinger proposes a transaction tax on all trades. Such a burden would discourage "short-termism"—traders that go in and out of positions in rapid fire to turn a quick profit who have a disproportionate and often irrational control over stocks and commodities.

Of course, a transaction tax is probably the last thing on any regulator's mind at this point. Today, they're squarely focused on the wild goose chase instead.