Barry Diller, one of the nation’s most influential executives in media and entertainment, has resigned as chairman of the board of Live Nation, effective...

Barry Diller, one of the nation’s most influential executives in media and entertainment, has resigned as chairman of the board of Live Nation, effective at the company’s next board meeting, multiple news outlets are reporting today, September 29.

The surprising move comes after a rough summer for the company, which has seen both ticket sales and its stock price perform well below expectations. Diller reportedly made the announcement to board members during a meeting yesterday, but a date for the next board meeting has not been disclosed.

In a statement to The Hollywood Reporter, which first reported the story, Diller said he had always planned to leave at some point once the company’s merger with Ticketmaster was complete. He will remain a member of the board.

“I have always said, since the merger of Ticketmaster and Live Nation, that I only planned to stay as chairman through the transition and integration of the two companies. It’s been almost a year and I informed the board today that while there was no rush, the board should start the process now to appoint a new chairman,” he said.

Yet, despite the positive spin, reports have surfaced that Diller clashed with other board members over the direction of the company, including Irving Azoff, the company’s executive chairman, who is now in line to possibly become the next board chairman. Diller is believed also to have clashed with Ariel Emanuel, the Hollywood agent and brother of White House Chief of Staff Rahm Emanuel, and nemesis John Malone, chairman of Liberty Media Corp., who has a history of sparring with Diller over media matters.

Malone and Liberty own close to 15 percent of Live Nation, but Malone sought a larger stake, and his influence on the board is thought to be substantial.

In a post on his Twitter account today, Azoff dismissed the reports of friction within the board.

“As usual the press reports are ridiculous,” Azoff wrote. “It was always Barry Diller’s intention to step down from [Live Nation Entertainment Chairman of the Board] during first year after [Ticketmaster/Live Nation] merger. I look forward to continue to work with him during his time on the board. I thank him for the many years of dedication and loyalty to everyone at [Ticketmaster].”

A Live Nation spokesperson did not reply to a message seeking comment.

Within months of receiving Department of Justice approval of the merger with Ticketmaster, Live Nation’s stock was trading in the $16 range and seemingly heading north, but a spate of canceled concerts and tours – due to poor ticket sales in the rough economy – began to eat away at the company’s share price, which has fallen at times by more than 40 percent. The stock trades under the symbol LYV, and it closed at $9.85 on Tuesday, September 28.

A conference call in July designed to assuage investor concerns did the opposite, which prompted Stifel, Nicolaus & Company analyst Ben Mogil to eventually lower his rating of the company from a “buy” to a “hold.”

Subsequently, in yet another move to calm investor fears, Live Nation President and CEO Michael Rapino recently told a group of investors that for 2011, the company would negotiate lower guaranteed payments to artists whose tours the company promotes.