Charles Dolan has stepped down as executive chairman of AMC Networks, marking the end of an era for the cable industry.

Dolan, 93, ranks among the earliest pioneers of cable TV. The telecom entrepreneur had the foresight to wire parts of Manhattan for cable service in the 1960s and in 1971 launch the pay TV service that became HBO. He’s been chair of AMC Networks since the company was spun off from the Dolan family’s former cable empire, Cablevision, in 2011.

AMC Networks board member James Dolan will replace his father as non-executive chairman of the company. Charles Dolan will shift to chairman emeritus. Charles Dolan’s net worth is valued by Forbes at $4.7 billion following the sale of Cablevision to Altice USA for $17.7 billion in 2016.

“The Dolans have led this company from its inception, and both Charles and Jim have provided vision, guidance and support through its long history of growth and evolution,” said Josh Sapan, president-CEO of AMC Networks. “We look forward to their continued leadership as AMC Networks continues to stand out in a crowded environment through the strength and quality of our content and ability to forge strong and lasting relationships with viewers and fans.”

AMC Networks also disclosed Tuesday that Sean Sullivan, executive VP and chief financial officer, will leave the company next month to join Sirius XM Satellite Radio. His role will be replaced. Sullivan’s decision to resign “was not related to any disagreement with [AMC] on any matter relating to [AMC’s] operations, policies or practices,” AMC said in a Securities and Exchange Commission filing.

AMC is in the midst of launching a $250 million stock buyback initiative structured as a tender offer for shares at a price range of $22.50 to $26.50. AMC stock was down nearly 8% on Tuesday, closing at $20.77. AMC shares are down about 47% for the year to date amid the macroeconomic turbulence caused by the pandemic as well as the specific challenges for the ad-supported basic cable sector that is the core of the company’s earnings.

The tender offer, described as a “modified Dutch auction,” is meant to signal the company’s faith that the stock will return to pre-pandemic levels.

“AMC Networks has a strong financial position and the proposed tender offer is a significant expression of strength and the Board’s confidence in our company’s future,” Sapan said.