Among the best known superstar CEOs is Elon Musk. While Tesla's directors have acknowledged that Musk is indispensable to the company's value, they have themselves been sued for allegedly breaching their fiduciary duties for failing to oversee and control Musk. After several of those suits were filed in 2018, the Tesla board decided not to renew its directors and officers (D&O) insurance due to "disproportionately high premiums." Instead, Tesla entered an agreement with Musk whereby he would personally provide insurance for Tesla's board members. D&O insurance acts as professional liability insurance, protecting the assets of an individual director or officer from claims the company cannot or will not indemnify. Significantly, most states prohibit a corporation from indemnifying directors and officers for any settlement portion of a derivative claim if they are found personally liable to the corporation for a breach of fiduciary duties, like failure to oversee their CEOs.