Most people don't have one CEO title, let alone two.
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Elon Musk, who runs both Tesla and SpaceX, was joined in the rare dual-CEO club this week when Jack Dorsey was named CEO of Twitter and said he will also continue to run his payments processing company, Square.
While Musk is clearly passionate about the work he does at both of his companies, he had some surprising advice for anyone wondering what it's like to be at the helm of two businesses.
"I wouldn't recommend running two companies," Musk said onstage during a Vanity Fair New Establishment Summit panel. "It decreases your freedom quite a lot."
Musk said he spends 70 percent of his time on engineering and design, according to The Verge, with 2 to 3 percent on media requests and speaking engagements.