What Is Fiduciary Duty?
A fiduciary is someone entrusted with power over another party's assets or interests, and the law holds fiduciaries to a higher standard than ordinary contracting parties. Corporate directors and officers owe fiduciary duties to the corporation and its shareholders. The same principle binds trustees managing trust assets, general partners running investment funds, ERISA fiduciaries overseeing retirement plans, and registered investment advisers, who owe duties to clients under the Investment Advisers Act of 1940.
Because most large US companies are incorporated in Delaware, Delaware courts have built the most influential body of fiduciary duty law. Their decisions define when boards can be sued, what standard of review applies, and how directors must behave when selling the company. For anyone working in M&A, these doctrines are practical constraints that shape how every board process gets run, documented, and defended in court.
The Duties of Care and Loyalty
The duty of care requires directors to make informed decisions—reviewing materials, questioning advisers, considering alternatives, and deliberating before acting. The duty of loyalty prohibits self-dealing and requires directors to put the company's interests ahead of their own, covering conflicts of interest as well as conscious disregard of duty under the good-faith obligation. Courts apply the business judgment rule as the default standard, presuming that informed, disinterested directors acted properly and declining to second-guess outcomes.
Heightened standards apply in specific situations. Under the Revlon doctrine, once a board decides to sell the company for cash, its duty narrows to obtaining the best price reasonably available for shareholders. Transactions involving conflicted controlling shareholders can trigger entire fairness review, the most demanding standard, which requires proof of both fair dealing and fair price. Boards manage this risk with special committees of independent directors and third-party fairness opinions.
Why Fiduciary Duty Matters in M&A and Investing
Fiduciary duty shapes deal mechanics that bankers touch daily. Go-shop provisions exist so a board can demonstrate it sought the best available price, and fiduciary-out clauses let a target board accept a superior proposal despite a signed merger agreement. Fairness opinions from investment banks give directors a documented basis for approving a transaction. Nearly every large public deal draws shareholder litigation testing whether the board met its duties along the way.
The concept extends across the buy side as well. Fund general partners owe duties to their limited partners, a recurring source of SEC enforcement around fees and conflicts of interest. Financial advisers operating under a fiduciary standard must place clients first, a stricter bar than the suitability standard historically applied to brokers. Understanding who owes duties to whom is essential context for interpreting almost any governance dispute or deal controversy.
