(Reuters) - Dish Network Corp raised its buyout offer for Clearwire Corp to $4.40 per share, valuing the wireless service provider at $6.5 billion and topping a rival bid by Sprint Nextel Corp bid by nearly 30 percent.
Sprint, the No. 3 U.S. mobile service provider, already owns just over 50 percent of Clearwire's shares and had increased its offer to $3.40 per share last week under pressure from activist shareholders.
Dish, which is also locked in a battle with Japan's SoftBank Corp to acquire Sprint, raised its bid just two days before the Sprint offer goes to a vote.
"The Clearwire spectrum portfolio has always been a key component to implementing our wireless plans of delivering a superior product and service offering to customers," Charlie Ergen, Dish chairman and co-founder of Dish, said in a statement.
Dish's offer values Clearwire at $6.47 billion, according to its shares outstanding as of May 29.
Clearwire shares were trading up 23 percent at $4.23 after-hours on Wednesday after closing at $3.43. Sprint was up less than one percent, and Dish stock fell 2 percent to $39.25 in after-hours trade.
A spokesperson for Clearwire said the company's special committee would review Dish's revised bid, and had not made any determination to change its recommendation of the current Sprint transaction.
A Softbank spokesman was not immediately available to comment, while a Sprint spokesman declined comment
(Reporting by Garima Goel in Bangalore; Additional reporting by Zeba Siddiqui in Bangalore and Sinead Carew in New York; Editing by Richard Pullin)