A major investor advisory firm has recommended against shareholder approval of T-Mobile USA’s pending merger with MetroPCS.

According to Bloomberg, Institutional Shareholder Services Inc. told MetroPCS shareholders to vote against the deal next month.

In a report to investors, ISS says it’s opposed to the deal because it feels that MetroPCS could do better on its own, even though MetroPCS would need to acquire more spectrum to stay competitive. “The question remains, ‘Why now?’” ISS said in its report. “Absent merging with T-Mobile, PCS will still have $1.5 billion of cash to dedicate to new spectrum in some way and could continue operating as a standalone company.”

The news agency also reports that Paulson & Co., which holds nearly 10 percent (and has the largest single-stake in the company) has come out against the deal, while the second-largest owner is for it.

“If anyone is being greedy here, it is Deutsche Telekom (T-Mobile’s German parent company),” Paulson & Co. said, as reported by Bloomberg. “While we support industry consolidation, the current proposal is a bad deal for MetroPCS shareholders. We believe MetroPCS is worth more as a stand-alone company."

Should the shareholders sign off on the deal, the deed will be finally done, as US regulators have given the green light.