Whatever the reason - and media today have mentioned the names of two women - Hugh Marks is leaving Nine Entertainment, after an upbeat annual meeting and an exciting five years.

In a message to colleagues this morning, he says he has decided "the time is right" to begin the process of moving on, an announcement which coincides with a Sydney Morning Herald interview in which he talks of progressing his relationship with former managing director of commercial Alexi Baker.

A statement to the market will be made on Monday, and then a formal process will begin "for both internal and external candidates" for his replacement. Industry website TV Blackbox says it understands former head of Fairfax Media's Australian metro publishing division and current Nine chief digital and publishing officer Chris Janz, and Stan chief executive Mike Sneesby are the frontrunners.

Marks looks back on five years with Nine, notably engineering its acquisition of Fairfax and Macquarie Media, and stitching together the three businesses - "each with their own structural challenges," he says - into "a business that now has a diversified revenue base across both advertising and subscription, and that has a clear growth strategy for decades to come".

That legacy is being cheerfully ignored by print and social media, and after having had his marriage break down and questions asked about his relationships with two former staffers, he may have decided he simply doesn't need or want the intrusion any more.

News Corp ran reports in May following his separation including a paparazzo video of him picnicking near Mosman, Sydney with executive assistant Jane Routledge - with whom he has denied any romantic relationship - and this week Nine chairman Peter Costello was asked about this at the annual meeting.

Guardian Australia reported today that Marks was now in a "committed relationship" with former Nine commercial director Alexi Baker, but Marks says in the SMH it is "still early days".

In the Sydney Morning Herald - which Nine owns - today, Marks expressed surprise at the interest in his private life. "There's a lot of gossip and a lot of that gossip is out of control ... and that sort of shocks me a bit that anyone is interested and that people can make shit up," he said.

He talked of "getting into a good place personally", a reference to his relationship with Baker, with whom he had worked closely on projects including the Fairfax merger. Part of her reasons for leaving was so they could "progress" their relationship unimpeded by respective corporate responsibilities, he said.

In his statement to colleagues today, Marks said Nine had demonstrated the importance of great content, "be that in the powerful and unique journalism we create every day, across all platforms, or in entertainment, where the shows we build become household names and engage Australians in their millions.

"Because at the end of the day, we are, and will remain, a content business."

He thanked chairman Peter Costello for "the extraordinary support he has given to me and to the entire business over the past five years".

"I leave knowing that Nine has an incredibly strong management team leading it across all its businesses. And of course, a depth of passion and drive and commitment right through all of our people."

Of Marks' stewardship of the business, Mumbrella founder Tim Burrowes made the point this weekend that if he'd bought $100-worth of Nine shares four years back, they'd be worth about $250 now. Compare that with $30 for $100 spent on Seven West shares at the same time... or losing your money on Ten.

Peter Coleman

Pictured: Hugh Marks answers questions at the Inform News Media Summit in 2018 (picture GXpress)