The Dolan family that controls Cablevision Systems Corp. (CVC) said on Monday it offered to take the U.S. cable operator private in a $7.9 billion deal that would also spin off its cable networks and sports team businesses.

Cablevision (search) shareholders would get $21 a share in cash plus shares in Rainbow Media (search), which includes: American Movie Classics, Independent Film Channel, Women's Entertainment channel as well as five regional sports networks, the New York Knicks basketball team, the New York Rangers hockey, among other assets, according to a press release.

Assuming a value of $12.50 a share for the Rainbow Media assets, the company said the total value of the offer of $33.50 a share, which represents almost a 25 percent premium over Friday's closing price and 6 percent premium over its 52-week high.

Shares rose 24 percent in premarket trading to $33.30, just shy of the premium offered by the Dolans, from Friday's New York Stock Exchange close of $26.87.

The offer comes amid concerns over the growth prospects for cable companies, some of which are losing subscribers to satellite television companies such as DirecTV Group Inc. (DTV) and EchoStar Communications Corp. (DISH) At the same time phone companies are investing billions of dollars into their lines to offer competing video service.

Charles Dolan (search) is Cablevision's chairman, while his son James is the chief executive officer. If the deal is accepted, Charles is expected to be chairman of privately-held Cablevision, while James would be chairman and chief executive of Rainbow Media.

"We strongly believe that a long-term, entrepreneurial management perspective — not constrained by the public markets' tendency to focus on short-term results — will better enable the cable company to meet its competitive challenges," the Dolan family said.

Cablevision would become the third major cable company to take itself private after Cox Communications and Insight Communications.

In a letter to the board, the family said it expects the board to form an independent committee with its own legal and financial advisors to respond to the offer. The family also noted that it is interested only in its offer and will not sell its stake in Cablevision.

The Dolans are being advised by Merrill Lynch and Banc Of America, which have agreed to finance cash portion of the deal. The family said that it needs $6.8 billion to complete the deal.