CNN chief Jim Walton says he is quitting, saying the company needs new leadership at a time its flagship US network is suffering through some of its poorest ratings ever.
Walton built the company into a profitable international news organisation in his 10 years as president of CNN Worldwide, and said it is on track for record profits this year. But the US network is the most visible part of the business and is now entrenched in third place behind rivals Fox News Channel and MSNBC in prime time.
He announced the decision in an email to staff on Friday. He will continue until the end of the year while the company sought a successor.
Walton said he's been talking to his boss, Turner Broadcasting chairman Phil Kent, about leaving since the first few months of the year. CNN is owned by Time Warner.
"I feel really strongly about a number of parts of this company," Walton said. "We're having a really strong year internationally and in mobile. It's clear there's a lot of spotlight on CNN's US performance and it's reasonable that there is that spotlight."
CNN's US network had its worst-ever ratings for a second quarter, down 40 per cent for some of its prime-time shows. The decline was notable in May, when CNN faced tough competition from broadcast networks during a slow news period and its ratings were compared to a year earlier, after the Osama bin Laden killing.
It hasn't improved appreciably since, with veteran newsman Wolf Blitzer often losing in the ratings to broadcast novice Al Sharpton on MSNBC. Piers Morgan's show has been a bright spot this month.
The network was also embarrassed by initially reporting incorrectly the US Supreme Court's decision on President Obama's health care law, then taking longer to correct itself than Fox, which made a similar error.
Walton believes CNN's strength lies in being a nonpartisan news source and its reputation would be damaged worldwide if the US network changed.
Walton, 54, said he doesn't expect that to change after he leaves.