U.S. stocks were trading mixed Monday as the Dow Jones Industrial Average recently added 14.6 points to 13344, the Standard & Poor’s 500-stock index was about flat at 1429 and the Nasdaq Composite slipped 2.5 points to 3041. Among the companies with shares expected to actively trade in Monday’s session are Clearwire Corp. (CLWR), Citigroup Inc. (C) and Amedisys Inc. (AMED).

Japan’s Softbank Corp. (9984.TO) will buy a 70% stake in U.S. mobile carrier Sprint Nextel Corp. (S, $5.75, +$0.02, +0.26%) for about $20 billion, the biggest-ever overseas acquisition by a Japanese firm. Sprint shares reacted modestly to the confirmed deal, a highly complex effort under which the Japanese carrier will buy 55% of outstanding Sprint shares for $7.30 each, among other transactions. Shares of ailing wireless network operator Clearwire Corp. (CLWR, $2.81, +$0.49, +21.16%)–in which Sprint owns a large stake–surged, however. People familiar with the matter have told The Wall Street Journal that Softbank eventually wants Sprint to sort out the complicated relationship in which it holds much of Clearwire’s stock but doesn’t control the company.