“Blue Horseshoe Loves Yahoo.” As Carl Icahn officially launches a proxy throwdown at Yahoo (NSDQ: YHOO), Reuters reports that the Paulson Fund, a top hedge fund run by investor John Paulson, has amassed a 50 million share stake, which represents around 3.6 percent of the total. Paulson was one of the most highly compensated hedge fund managers last year, having made a significant bet against the subprime mortgage market. He’s also known for betting on merger arbitrage situations—so Carl Icahn’s attempt to play matchmaker between Yahoo and Microsoft (NSDQ: MSFT) would be right up his alley.

Updated: The filing disclosing the 50 million share stake in Yahoo is here. In a statement, Paulson expressed “dissapointment” that the company failed to close a deal with Microsoft and that he hoped the coming month-long proxy fight would not be necessary. But yes, if it comes to it, those shares will be voted towards the Icahn slate. (via MarketWatch)

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• Updated: Icahn May Launch Yahoo Proxy Fight: Reports