U.S. Markets close in 2 hrs 32 mins

Siris Capital buying TNS for $516.6 million

RESTON, Va. (AP) -- A group led by private equity firm Siris Capital Group is buying data communications company TNS for $516.6 million.

Siris will pay $21 a piece for each share, a 44 percent premium to Monday's closing stock price. The companies value the total deal at around $862 million.

Shares of TNS jumped $6.26, or 43 percent, to $20.82 on Tuesday. The stock has traded in a 52-week range of $13.59 to $22.84.

TNS Inc. has approximately 24.6 million outstanding shares according to FactSet. The company is allowed to seek out alternative third-party buyout proposals for a 30 day period.

The deal, which was unanimously approved by TNS's board, is expected to close in 2013's first quarter.