Don't forget that often (but certainly not always) CEOs will look ahead and try to get a feel for which locations may be a good fit both for their personal and company affairs. Usually due to taxation, regulatory, hiring, cultural, cost of living and a range of other realities. They may make the move themselves ahead of their company's move making it seem like the company later moved merely because of the CEO's new location, but they'd already made the decision that the company move would follow as the sensible thing.