Pershing Square International Ltd., the main hedge fund of activist investor William Ackman, lost 12 percent in 2008, according to a letter obtained by Bloomberg News.

The hedge fund fell 0.2 percent in December, the letter to investors said.

The New York-based fund’s winning bets last year included short positions in MBIA Inc. and Financial Security Assurance Holdings Ltd., and investments in Wachovia Corp. and Longs Drug Stores Corp.

It lost money on investments in retailer Target Corp., book store chains Borders Group Inc. and Barnes & Noble Inc. and Dr. Pepper Snapple Group Inc.

Ackman’s Pershing Square Capital Management LP manages $4.78 billion.