It comes amid tensions between Leslie Buckley and Robert Pitt
The CEO of Independent News and Media (INM) has abstained from voting for the re-election of Chairman Leslie Buckley.
It follows a disagreement between both men over the possible purchase price of Newstalk.
Chief executive Robert Pitt made a protected disclosure under whistleblower legislation after they both got different valuations of the radio station, with the chairman's substantially higher.
The matter was also referred to the Office of the Director of Corporate Enforcement (ODCE), who are investigating.
At its Annual General Meeting (AGM) in Dublin on Wednesday Mr Pitt abstained from voting for Mr Buckley, who was nonetheless re-elected.
At the close of the meeting, both men declined to comment.
Newstalk is owned by Denis O'Brien, a majority shareholder in INM.
Newstalk's business editor Vincent Wall says it is highly unusual for a CEO not to vote for the chairman's re-appointment.
"For the re-election of the Chairman Leslie Buckley alone, Mr Pitt didn't raise his hand either for or against - in other words he abstained.
"(This) is highly usual for the chief executive of a public company not to show pro-active support for his chairman."
"There's certainly clear evidence that there are still serious issues between the chief executive and the chairman.
"That can't be good for any public company - it distracts from management time, it means the relationship isn't good - and they're the key people in running any company, let alone a publicly-quoted company.
"We also of course have to wait for the report of the Office of the Director of Corporate Enforcement as to what they found, or not".