I've always thought it weird that Jack was a part-time CEO, but there are certainly CEOs that have at least as large of a "thing to manage", even if they aren't technically two companies.

Facebook is a giant VR company and three-four giant social networking companies. Google runs phone infrastructure, search, self driving cars. Amazon is a giant retail outlet plus a giant cloud services company.

Is running both a social media company and a fintech firm that different, even though they aren't grouped under a single corporate owner?