The idea that company directors have a fiduciary duty to maximise shareholder value is mostly a myth: it is one of those ideas that many economists like that seem to simplify things but actually can't be made to work. James Kwak has a nice article (Medium, sorry) on this
> The specific fiduciary duties of corporate directors...are common law: legal principles that have been established by courts in the process of adjudicating cases over the years. As it turns out, in Delaware, which is the state that matters—not only because most large corporations are incorporated there, but because courts in other states tend to look to Delaware law when dealing with new issues of corporate law—there are exactly two fiduciary duties: the duty of loyalty and the duty of care.
> They duty of care is basically the duty to pay attention to your job: in essence, to make decisions on the basis of reasonably adequate information. There is an academic controversy—fueled by careless uses of language by the courts—about whether the standard of conduct is negligence or gross negligence. But the point here is that the duty of care isn’t a duty to do any particular thing, such as maximize profits.
> The duty of loyalty is marginally more complicated. This duty (like the duty of care) existed in agency law—the law governing the relationship between agents, such as employees, and principals, such as companies—before corporations became widespread in the nineteenth century. There, the duty of loyalty essentially meant that you couldn’t use your position as an agent to make a personal profit—by stealing directly from the principal, via a transaction with the principal, or, in the famous case of Reading v. Regem, by using your British Army uniform to help smugglers during your off hours.
https://medium.com/bull-market/there-is-no-effective-fiducia...
> The specific fiduciary duties of corporate directors...are common law: legal principles that have been established by courts in the process of adjudicating cases over the years. As it turns out, in Delaware, which is the state that matters—not only because most large corporations are incorporated there, but because courts in other states tend to look to Delaware law when dealing with new issues of corporate law—there are exactly two fiduciary duties: the duty of loyalty and the duty of care.
> They duty of care is basically the duty to pay attention to your job: in essence, to make decisions on the basis of reasonably adequate information. There is an academic controversy—fueled by careless uses of language by the courts—about whether the standard of conduct is negligence or gross negligence. But the point here is that the duty of care isn’t a duty to do any particular thing, such as maximize profits.
> The duty of loyalty is marginally more complicated. This duty (like the duty of care) existed in agency law—the law governing the relationship between agents, such as employees, and principals, such as companies—before corporations became widespread in the nineteenth century. There, the duty of loyalty essentially meant that you couldn’t use your position as an agent to make a personal profit—by stealing directly from the principal, via a transaction with the principal, or, in the famous case of Reading v. Regem, by using your British Army uniform to help smugglers during your off hours.