All of the following are common-law fiduciary principles except:

In the context of common-law fiduciary principles, the duties associated with a fiduciary generally focus on the responsibilities of the fiduciary toward the beneficiaries or clients. The duty to administer client assets in line with the governing document, the duty to invest client funds prudently, and the duty to act in the best interest of beneficiaries are well-established principles.

The duty to generate a reasonable return to the trust organization from fiduciary services, however, is not a common-law fiduciary principle. This particular duty appears more centered on the profitability of the fiduciary entity rather than focusing on the best interests of the beneficiaries. A fiduciary's primary obligation is to act in the best interest of their clients, ensuring that their actions are in alignment with the expectations set in governing documents and that they manage and invest those assets prudently. Thus, option B stands apart from the other established fiduciary duties, which prioritize the needs and interests of clients as dictated by common law.