From Bloomberg:

The U.S. Securities and Exchange Commission and the U.K. Financial Services Authority spurred the "mother of all bear squeezes" with their ban on short sales of financial stocks, according to Ashburton Ltd.'s Peter Lucas.

The SEC halted short selling today in shares of 799 companies through Oct. 2, and the FSA enacted a similar ban yesterday until Jan. 16. The Standard & Poor's 500 Financials Index climbed 12 percent yesterday on expectations the SEC would announce a ban and Congress would take steps to shore up markets. U.K. banks including Barclays Plc, Royal Bank of Scotland Group Plc and Lloyds TSB Group Plc rose more than 50 percent today.

The CHART OF THE DAY shows the jump in short interest this year in the six worst-performing financial shares in the S&P 500 -- American International Group Inc., Washington Mutual Inc., National City Corp., Genworth Financial Inc., XL Capital Ltd. and Wachovia Corp. -- along with the percentage of each company's shares available for trading that were sold short at the end of August. Short interest is set at 100 on Dec. 31.