Let the Disney speculation begin. Seems like everyone in and around Wall Street has a thought about who might be heir apparent to CEO Bob Iger now that the exec long thought to have secured that role — COO Tom Staggssays he’ll step down May 6. Staggs will stick around as an advisor through the end of the fiscal year in September.

Facebook’s Sheryl Sandberg, who’s on the Disney board? Former Fox No. 2 Peter Chernin? Another former Fox No. 2 Chase Carey? CBS’ Les Moonves? Sure, why not?

But even the speculators acknowledge that while lots of people could lead the company when Iger’s contract expires in mid-2018, there’s no obvious candidate — especially from a younger generation — to run a sprawling organization with interests in TV, digital, movies, and theme parks. Indeed, it isn’t even clear why the board declined to formally designate Staggs as successor, which is believed to have prompted him to bolt.

“We have no reason to believe there was any specific project failure or decision(s) that triggered” the decision, Bernstein Research’s Todd Juenger said. “Begging the question, if not Mr. Staggs, then who?”

That’s why some believe Disney might try to reassure Wall Street — which hates uncertainty — by extending Iger’s contract. Again.

“In 2011, Mr. Iger set a plan to step down as CEO in April 2015, only to extend his plans to remain CEO until 2018 to oversee the successful integration of Lucasfilm and theme park expansion plans into China,” Nomura Securities’ Anthony DiClemente says. “To borrow a phrase, the best successor to Bob Iger may very well be Bob Iger.”

The 55th Annual GRAMMY Awards - Pre-GRAMMY Gala And Salute To Industry Icons Honoring L.A. Reid - Show

Iger is hardly over the hill at 65. That makes him just a year younger than Moonves, a year older than Chernin, and a few years older than Carey.

If the board wanted someone younger to take the helm it might look at the next younger age bracket of A-list media moguls — those roughly Staggs’ age: That list would have to include NBCUniversal’s Steve Burke (57) and Discovery’s David Zaslav (56). But both have sweet deals and job security at the companies they run.

Image (8) SherylSandberg__140109185953-275x412.jpg for post 661030

Sandberg, at 46, offers a more distinct generational change. But aside from her work on Disney’s board, the Facebook exec has no experience managing TV, film, or theme parks, Disney’s core businesses.

Disney also has a deep bench of inside talent. But when Staggs’ star rose, the company lost others thought to rival him for the top job including former CFO Jay Rasulo and former Disney Media Networks co-chair Anne Sweeney.

It might take time, then, not only to figure out who should replace Iger, but to groom him or her for the job — and ensure that investors are comfortable with the choice.

It’s shocking that Disney finds itself in a situation where it’s still wrestling with succession questions. Yet there’s a sense among company watchers that the best way to answer those questions is for Iger to extend his contract once again.