Cablevision said it will "fully cooperate" with separate investigations by the SEC and the U.S. Attorney’s Office into its stock-option grants in the ’97-’02 period. The investigations, revealed in CVC’s SEC 8-K filing Wed, stem from the MSO’s earlier disclosure that it might need to restate results after finding inconsistencies related to the grants (Cfax, 8/9). CVC also warned of potential class-action lawsuits and "additional derivative actions" related to the matter but said it wouldn’t file further 8-Ks describing them if they occur. In addition, CVC subsidiary CSC Holdings announced that in light of its Aug 8 disclosure it would extend until Sept 8, 5pm ET, its offer to exchange up to $500mln aggregate principal amount of its 6-3/4% Senior Notes due ’12 for an equal aggregate amount of its registered 6-3/4% Series B Senior Notes due ’12. The original notes were issued and sold in a private placement in Apr ’04.