A new entity has joined the opposition of T-Mobile's proposed acquisition of MetroPCS. One month after MetroPCS's largest shareholder came out against the deal, advisory firm Institutional Shareholder Services has called the merger "unfair" and advised MetroPCS's shareholders to vote it down. ISS, a company that advises shareholders on to vote in corporate matters, raised several concerns with the deal, including the fact that the terms would require MetroPCS shareholders to give up control to Deutsche Telekom, a company that has been in charge of T-Mobile during a time that ISS feels the carrier has "vastly underperformed."

Additionally, ISS believes that MetroPCS would have enough money without T-Mobile to acquire more spectrum and continue to thrive on its own. ISS goes on to suggest that MetroPCS could be the target of a merger with a different company later on thanks to its "attractive assets."

Following ISS's recommendation that MetroPCS shareholders vote against the T-Mobile deal, MetroPCS issued a response on the report. The carrier describes ISS's report as having "material flaws" and reaching the "wrong conclusion," adding that if its shareholders do vote the merger down, they won't be able to enjoy its benefits and could ultimately lose value in their holdings. MetroPCS also points out that Egan-Jones, another advisory firm, has recommended that MetroPCS stockholders vote in favor of the merger with T-Mobile.

The proposed T-Mobile-MetroPCS deal was originally announced back in October 2012, and MetroPCS recently confirmed that the merger has earned all of its necessary regulatory approval. That means that the last big hurdle on its path to completion is the MetroPCS shareholder vote, which is scheduled for April 12. In addition to ISS's opposition to the deal, two hedge funds that are also MetroPCS stockholders have voiced their dissatisfaction with the T-Mobile merger, including the largest shareholder that owns a 9.9 percent stake in MetroPCS. Both MetroPCS and T-Mobile are still confident that the merger will happen, though, despite resistance from what T-Mobile CEO John Legere recently described as "greedy hedge funds."

Via The Wall Street Journal, ISS (PRNewswire), MetroPCS (PRNewswire)