New Viacom Inc. Chairman Philippe Dauman is already on the defensive after the media company fell short of revenue expectations for the fifth quarter in a row.

Just a few days after replacing ailing Sumner Redstone as executive chairman, in addition to his continuing role as chief executive, his honeymoon period in the top job came to an abrupt end Tuesday, ABCNews.com reports.

In a quarterly earnings conference, he defended himself in a heated exchange with analysts about the lackluster fiscal performance of the parent company of MTV and Paramount Pictures.

The call ultimately didn’t inspire investor confidence, with Dauman being pressed on why shares fell more than 17 percent to a 52-week low Tuesday and were trading at $34.44, more than 60 percent below the peak in July 2014. Dauman said while the stock beat the S&P 500 average for five years running, the share price decline has been, “accentuated in the recent past by a lot of noise.” He indicated the “noise” referred to the dispute over who will control Viacom going forward when Redstone passes away.

Three weeks ago, Viacom awarded Dauman a $17 million contract renewal bonus that boosted his overall pay by 22 percent to $54.2 million last year.

Corporate governance experts say Dauman’s dual role as chief executive and board chair leaves him unaccountable, especially since the majority control of the company is in the hands of Redstone, whose mental competence has been in question.