NEW YORK (AP) - Sprint's new owner is replacing its longtime CEO with a Bolivian billionaire and entrepreneur after dropping its bid for rival wireless carrier T-Mobile US.

Marcelo Claure, the CEO of Miami-based cellphone distributor Brightstar, will replace Dan Hesse on Monday, Sprint Corp. said Wednesday.Claure, 43, had been CEO of Brightstar Corp., which is part of Softbank Corp. of Japan. Softbank bought 70 percent of Sprint last year.Sprint shares fell 19 percent Wednesday after its chairman and incoming CEO talked about adopting aggressive tactics to compete with AT&T and Verizon, likely including price cuts.The Wall Street Journal said Tuesday that Sprint decided not to pursue the merger of the No. 3 and No. 4 U.S. carriers. The paper cited unnamed people familiar with the matter. The merger would have faced tough opposition from U.S. regulators who want to preserve competition among wireless carriers, and Wall Street analysts saw little chance of the deal being consummated.