Mediacom Communications Corp said founder and chief executive withdrew his offer to take the cable television operator private after a special board committee rejected his sweetened bid.

Shares of the Middletown, New York-based company slumped as much as 20 percent to $5.50, below CEO Rocco Commisso's initial offer of $6 per share that was announced in May.

The stock, which had gained 29 percent since Commisso made his offer public, was trading down 16 percent at $5.75, making it the top percentage loser on Nasdaq.

I am very disappointed with the highly unusual process and ground rules established by the special committee and its financial and legal advisers to evaluate my proposal, Commisso said in a statement, but did not reveal his latest offer.

Commisso, who founded Mediacom in 1995, currently owns 87.2 percent of the aggregate voting power of class A and class B shares of the company.

The CEO said he terminated discussions with the special committee and reiterated that he does not intend to sell his Mediacom shares.

Mediacom competes with companies such as DirecTV Inc and Dish Network Corp in smaller cities in mid-west and south-east regions of United States.

(Reporting by Manasi Phadke in Bangalore; Editing by Unnikrishnan Nair)