Likely anything that goes beyond missing out on compensation (ex: unvested RSUs) or even clawing back some comp would violate labor laws. CEOs are still employees, and legislation regulating employer-employee relations trumps all contracts.
There are many many instances where the CEO is not an employee, but they operate via their own legal entity. To be honest I don't know how this works at larger companies.
fred_is_fred · · focus · HN ↗
next_xibalba · · focus · HN ↗
jtwaleson · · focus · HN ↗
SkyPuncher · · focus · HN ↗