John Paulson is moving against MetroPCS.

The hedge-fund billionaire, whose Paulson & Co. hedge fund is the biggest shareholder of the wireless carrier, said yesterday he intends to vote against the proposed sale to T-Mobile.

“MetroPCS is contributing 42 percent to the pro forma company’s value but its shareholders are only receiving 26 percent of the pro forma company’s equity,” the firm said.

Paulson’s opposition throws the success of the deal into doubt.

T-Mobile, America’s fourth-largest carrier, has reached a deal to buy 74 percent of pre-paid leader MetroPCS in a stock and cash transaction.

The March 28 vote by shareholders is expected to be close, said a source.

Private-equity firm Madison Dearborn Partners, which in 2005 bought into MetroPCS and owns an 8.3 percent stake, supports the merger.

Paulson & Co., in a letter, said, “We believe that as an independent company MetroPCS will be able to pursue a higher value transaction with industry peers than previously made offers at significant premiums to MetroPCS’ current [$9.80] share price.

The hedge fund could be alluding to Sprint, which has been rumored to be interested in the company — but sources with direct knowledge of the situation said Sprint has no present plans to make a counter-proposal.