The companies are soon expected to face tougher competition from an emboldened Sprint, which has agreed to sell 70 percent of its shares to Japan's SoftBank Corp for $20 billion. P. Schoenfeld Asset Management LP, which says it owns about 2.5 percent of MetroPCS, is leading a proxy battle against the deal. Paulson & Co has a 9.9 percent stake, and Madison Dearborn owns about 8.3 percent of MetroPCS shares, according to the most recent public disclosures. MetroPCS shares have slid more than 8 percent since Oct. 1, 2012, the day before reports emerged that MetroPCS and Deutsche Telekom were in talks.