Charter Communications announced today that it has filed a registration statement with the Securities and Exchange Commission related to a proposed exchange offer of up to $309 million of its convertible senior notes.

Charter, the third-largest cable operator in the United States, said the exchange offer is to extend its debt maturities. The convertible senior 5.875 percent notes have a principal amount outstanding of $413 million, which are due in 2009.

Charter Communications Holding Co. is offering up to $595 million principal amount of new 7 percent convertible senior notes due 2027 in exchange for up to $309 million aggregate principal amount of its existing convertible notes. The exchange offer is valid for existing convertible notes tendered for exchange before Sept. 26.