Credit rating agencies have warned they are likely to downgrade Cablevision on the back of a bid by the New York company's controlling shareholders, the Dolan family, to take its cable business private in a deal worth $7.9bn (€6.5bn).

Cablevision, which is already rated high-yield by Moody's Investors Service, Standard & Poor's and Fitch, faces further downgrades that would increase its cost of borrowing in the debt capital markets.