Sprint Corp.'s shares surged 8.3% amid speculation that the company is coming closer to a merger with rival T-Mobile US Inc. The stock went up to $10.79 in New York, making it the biggest one day gain since Japan's Softbank Corp. acquired a majority stake in Overland Park. The deal between the third and fourth largest mobile phone services in the U.S. would give Verizon Wireless and AT&T Inc. more stout competition.