French telecommunications group Altice SA said it agreed to buy Suddenlink Communications in a deal valuing the company at $9.1 billion to enter the fast-growing U.S. cable sector.

Altice is buying 70 percent of Suddenlink from existing shareholders BC Partners, CPP Investment Board and Suddenlink management, it said in a statement on Wednesday. BC Partners and CPP Investment Board will retain a 30 percent stake.

"Our investment in Suddenlink, our first in the cable sector in the U.S., opens an attractive industrial and strategic avenue for Altice in the U.S., one of the largest and fastest growing communications markets in the world," Altice Chief Executive Dexter Goei said.

Suddenlink is the seventh-largest U.S. cable operator with 1.5 million residential and 90,000 business customers, according to Altice. Suddenlink generated $2.3 billion in revenue and over $900 million in earnings before interest, tax, depreciation and amortization (EBITDA) last year.

Shares in Altice, which is controlled by French billionaire Patrick Drahi, were 7 percent higher at 123.65 euros by 0719 GMT.

Drahi has turned Altice into a serial acquirer since taking it public in January 2014. Last year alone, the group used its French cable company, Numericable, to take over the country's second-largest mobile carrier, SFR, as well as snapping up Portugal Telecom and another operator in the Dominican Republic.

Altice has also held talks to buy Time Warner Cable Inc, people familiar with the matter said.

Time Warner Cable, which is in large U.S. markets such as New York and Los Angeles, is a much bigger bite for Altice, and it would also face competition from Charter Communications for the asset.

The Suddenlink deal gives the U.S. company an enterprise value of $9.1 billion and a valuation of 7.6 times EBITDA adjusted for synergies, Altice said.

Altice will finance the purchase with the help of $6.7 billion of new and existing debt at Suddenlink, a $500 million vendor loan note from BC Partners and CPP Investment Board, and $1.2 billion of cash.

The transaction is expected to close in the fourth quarter of 2015, Altice said.

JPMorgan, PJT Partners and BNP Paribas acted as financial advisers to Altice. Franklin, Covington, Mayer Brown and Ropes & Gray acted as legal advisers to Altice.