March 14 MetroPCS Communications Inc shareholder P. Schoenfeld Asset Management LP, which has been opposing the company's merger with Deutsche Telekom's T-Mobile USA, urged shareholders to vote against the deal.
The deal was approved by the U.S. Federal Communications Commission on Tuesday and needs to clear the shareholder vote on April 12.
In a letter to MetroPCS shareholders, P. Schoenfeld Asset Management, which had a 1.66 percent stake in the company as of Dec. 31, termed the deal "irresponsibly and inefficiently structured."
It said MetroPCS had more attractive options, including continuing on a stand-alone basis.
P. Schoenfeld Asset Management said it was preparing a "white paper" that would make a "compelling case" for voting against the deal.
The shareholder vote is one of the last remaining obstacles to the deal. While analysts had widely expected regulatory approval for the deal, the outcome from the shareholder meeting has been more difficult to predict.
P. Schoenfeld Asset Management also said it had hired financial adviser Houlihan Lokey to help evaluate the deal.
MetroPCS shares were up less than a percent at $10.19 in early trading on Thursday on the Nasdaq.