Which document outlines the fiduciary responsibilities for investment managers under ERISA?

The Plan Document is the definitive source that outlines the fiduciary responsibilities for investment managers under the Employee Retirement Income Security Act (ERISA). This document serves as a comprehensive guide for plan operations and clearly defines the roles and responsibilities of fiduciaries, which include investment managers. It specifies the duties related to managing the plan's assets, acting in the best interest of the plan participants, and adhering to the prudent man rule, which mandates that actions taken must be in line with what a prudent person would do in similar circumstances.

The Investment Policy Statement primarily serves to articulate the investment strategy and goals of a pension or investment plan but does not detail fiduciary obligations as comprehensively as the Plan Document. The Trust Agreement pertains to the legal relationship and terms under which the trust operates but may not specifically address the fiduciary standards required under ERISA. The IRS 5500 Form is an annual report filed by employee benefit plans to satisfy regulatory requirements; it provides information about the plan's financial condition, investments, and operations but does not define fiduciary responsibilities directly.

Thus, the Plan Document is critical in its role regarding ERISA, as it provides specific guidelines and legal backing for investment managers' fiduciary duties.