Dish Network is offering to buy Sprint Nextel Corp. in a cash-and-stock deal it values at $25.5 billion, saying its bid is superior to that of Japanese phone company SoftBank.

Sprint’s stock jumped almost 15 percent in premarket trading Monday.

SoftBank Corp. is seeking approval from U.S. authorities for its $20 billion purchase of a 70 percent stake in Sprint Nextel Corp. that would be Japan’s biggest foreign acquisition ever. Sprint previously said that it expected the deal with SoftBank to close during the summer.

The transaction, which was announced in October, was looked at as a way to position Sprint as a stronger competitor against rivals AT&T and Verizon.

Dish, an Englewood, Colo., satellite television company, said Monday that its proposed transaction includes $17.3 billion in cash and $8.2 billion in stock.

Sprint stockholders would receive $7 per share, which is a 13 percent premium to its Friday closing price of $6.22. This includes $4.76 per share in cash and 0.05953 Dish shares per Sprint share.

Dish said that the cash portion of its bid is an 18 percent premium over the $4.03 per share implied by the SoftBank offer, while the stock portion represents about 32 percent ownership in a combined Dish/Sprint company, as compared with SoftBank’s proposal of a 30 percent interest in Sprint alone.

Dish Network Corp. said that its offer is a 13 percent premium to the existing SoftBank offer. The company also said that its proposal would result in estimated cost savings of $11 billion.

In a letter sent to Sprint Chairman James H. Hance Jr., Dish Chairman Charles Ergen said that the company would fund the cash component of its bid with $8.2 billion of cash on its balance sheet and additional debt financing.

The letter also said that Dish would have preferred holding confidential talks with Sprint about its proposal, but that the existing agreement with SoftBank and impending deadlines related to its shareholder vote prompted Dish to confirm its offer publicly.

Dish added 14,000 TV subscribers in the fourth quarter, compared with a gain of 22,000 in the same quarter last year. It ended the year with 14.1 million subscribers. DirecTV has 20 million.

Shares of Sprint rose 91 cents, or 14.6 percent, to $7.13 — above the offered price — 90 minutes ahead of the market opening. Dish shares fell 63 cents, or 1.7 percent, to $37 in premarket trading.

(AP)