NEW YORK ( TheStreet) -- Sprint ( S) confirmed Thursday its' in discussions with Japanese firm Softbank about a possible "substantial" investment in the No. 3 U.S. telecom provider. "Although there can be no assurances that these discussions will result in any transaction or on what terms any transaction may occur, such a transaction could involve a change of control of Sprint," explained the Overland Park, Kansas-based company in a statement. Sprint added that it does not intend to comment further "unless and until an agreement is reached." Investors responded positively to the announcement, pushing Sprint's shares up 18.06% to $5.95. Early on Thursday, Reuters reported that the Japanese carrier is in talks to buy a majority stake in Sprint for more than 1 trillion yen ($12.8 billion). Sprint, which is keen to participate in industry consolidation, was recently rumored to be considering a counter-bid for MetroPCS ( PCS), which is merging with T-Mobile USA. MetroPCS and T-Mobile USA disclosed earlier this month details of their planned merger. The combined company will use T-Mobile's branding and have 42.5 million subscribers. MetroPCS shares tumbled 4.65% to $11.48 on Thursday. --Written by James Rogers in New York. Follow @jamesjrogers >To submit a news tip, send an email to: email@example.com.