Franck Muller leans on its in-house talent to push the limits of its tourbillon watches.

For Pierre-Michel Golay, master watchmaker at Franck Muller Watchland, making a new wristwatch means setting a new benchmark. Asked to create a timepiece “with a lot of hands,” he spent half a decade developing the massive, 36-complication Aeternitas Mega 4. “I had always wanted to make a very complicated watch,” he says, recalling the genesis of his 2009 magnum opus. “I suppose I got carried away.”

So when CEO …