After-Hours Movers Thursday: ConAgra Foods Inc, Healthways, Inc.

ConAgra Foods Inc CAG gained more than 7 percent to $41.95 in late trading after activist investor Jana Partners disclosed a 7.2 percent stake and said it may nominate board members and wage a proxy fight. Cousins Properties Inc CUZ rose more than 6 percent to $11.56 after the bell. The real estate investment trust didn't issue news Thursday. Oil States International, Inc. OIS gained about 5 percent in late trading Thursday to $42.59 a share. The energy services company closed down by 5.5 percent earlier. Avalanche Biotechnologies Inc AAVL rose 5 percent in the extended session to $16.92 a share. The company closed down earlier by a similar magnitude and is off about 24 percent during the past five trading days. Rex Energy Corporation REXX gained 4.6 percent to $5.22 in late trading after the company said it will sell its 60 percent stake in Water Solutions Holdings LLC for $66 million. Healthways, Inc. HWAY fell about 24 percent to $11.81 in late trading Thursday after the well-being improvement company reduced its outlook citing slower than expected business development. PBF Energy Inc PBF fell nearly 6 percent percent to $26.40 after the bell. The the oil refiner closed up earlier by 6 percent after it agreed to pay $322 million to acquire Chalmette Refining LLC, from ExxonMobil XOM and PDV Chalmette LLC. Merrimack Pharmaceuticals Inc MACK bounced down 9 percent to $11.06 a share after closing up 10 percent earlier. MedAssets, Inc. MDAS declined nearly 9 percent to $20.20. The health-care software company was little changed before the bell and didn't issue news Thursday. Macerich Co MAC declined about 5.5 percent to $77.95 in the extended session. The real estate investment trust with interests in regional shopping centers said the Philadelphia City Council approved measures that permit the redevelopment of a property there. PROS Holdings, Inc. PRO dropped 3.8 percent to $20.91. The software company didn't issue news.