BETHPAGE, N.Y. -- Cablevision Systems Corporation (CVC) today announced the appointment of Gregg Seibert to vice chairman. In addition to this new leadership position, he will continue to serve as the company’s chief financial officer, reporting to James L. Dolan, Cablevision president and chief executive officer. As vice chairman, Mr. Seibert, 57, will collaborate with Mr. Dolan and the senior management team on the formulation and implementation of Cablevision’s overall strategy, helping to position the company for long-term success in an increasingly competitive marketplace. He will work closely with Hank Ratner who also serves as a vice chairman of Cablevision. Cablevision Systems Corp.