The titular topic is addressed in the recent Chancery decision of McRitchie v. Zuckerberg, and corporate law scholar Professor Bainbridge provides scholarly insights about the topic and the decision on his blog, which includes the following money quote from the opinion:

Under the standard Delaware formulation, directors owe fiduciary duties to the corporation and its stockholders. Implicitly, the “stockholders” are the stockholders of the specific corporation that the directors serve, i.e., “its” stockholders. The standard Delaware formulation thus contemplates a single-firm model (or firm-specific model) in which directors of a corporation owe duties to the stockholders as investors in that corporation. That point is so basic that no Delaware decisions have felt the need to say it. Fish don’t talk about water.