Plan Administrator vs. Trustee vs. 3(38): Who Signs What
Five different parties can be called a “fiduciary” on the same 401(k) plan, and they carry entirely different liability. This page sorts out who holds the assets, who makes investment decisions, who signs the Form 5500 — and which of those jobs you are personally on the hook for right now.
The five roles, side by side
Almost every argument about 401(k) responsibility comes from mixing up two things: who decides, and who is accountable if the decision was wrong. ERISA separates them deliberately. Here is the actual division:
| Role | ERISA cite | What it controls | What it does not |
|---|---|---|---|
| Named fiduciary | 402(a) | Overall authority to control and manage plan operation. Must be named in the plan document. | Does not hold assets, and does not pick investments unless it also takes the 3(38) role. |
| Plan administrator | 3(16) | Reporting, disclosure and day-to-day compliance: Form 5500, participant notices, claims, the compliance calendar. | No authority over plan assets or investment lineup. |
| Trustee | 403(a) | Holds plan assets in trust. Exclusive authority over those assets unless the plan makes the trustee directed. | Does not run the plan, file the return, or select the menu when it is a directed trustee. |
| Investment adviser | 3(21) | Recommends investments. Shares fiduciary status for the advice given. | Does not decide. The plan fiduciary accepts or rejects each recommendation and keeps that decision. |
| Investment manager | 3(38) | Full discretion to select, monitor and replace plan investments. Must be an RIA, bank or insurance company and must accept the role in writing. | Does not administer the plan or sign the filing. |
The practical consequence: appointing a 3(38) does nothing for your Form 5500. Appointing a 3(16) does nothing for your investment lineup. Sponsors who believe they have “outsourced the fiduciary work” because they hired one of these are usually still carrying the other.
Who actually signs the Form 5500
The plan administrator signs it. Not the recordkeeper, not the trustee, not the advisor, not the TPA. Under ERISA the plan administrator is whoever the plan document names — and when the document is silent or names “the Company,” the statutory default is the plan sponsor. That means the employer.
In practice a named officer signs under penalty of perjury through EFAST2, attesting that the return is true, correct and complete. That signature is the whole point of the distinction. A recordkeeper can prepare beautiful numbers and a TPA can assemble the schedules, but neither one is attesting to anything. The person who signs owns the filing.
This is the gap most plans have. The Form 5500 sits between the recordkeeper, the auditor, the payroll system and the sponsor, and in most plans no party is contractually responsible for it hitting the deadline. The sponsor signs it — but the sponsor is usually a CFO or HR director with a day job. When a census runs late or the audit slips, the deadline is what gives.
When a 3(16) plan administrator is named in the plan document, that signature and the calendar behind it move off the employer. Admin316 signs and files the Form 5500 for the plans it administers. That is not an add-on to the service; it is the service.
Trustee: discretionary vs. directed
“Trustee” is the role sponsors most often misread, because there are two very different versions and the plan document decides which one you have.
Discretionary trustee
Holds exclusive authority and discretion over plan assets. Broad power, broad liability. Uncommon in small and mid-size 401(k) plans.
Directed trustee
Holds the assets but acts on the proper direction of the named fiduciary or a 3(38) manager. This is the standard arrangement in participant-directed 401(k) plans. The protection is real but it is not unconditional: a directed trustee may only follow directions that are proper, consistent with the plan document, and not contrary to ERISA. A direction that is plainly imprudent or prohibited does not become safe because someone else gave it.
Two things follow from that. First, “we have a directed trustee” is not a liability answer — somebody still has to be the named fiduciary giving proper direction, and that is usually you. Second, the trustee role and the administrator role are separate appointments. Having one does not fill the other. Our 403(a) directed trustee services cover the asset-custody side; the administration side is a different appointment.
What always stays with the employer
No provider can take these, and any provider claiming otherwise should worry you. These are settlor functions — business decisions, not fiduciary acts:
- Establishing the plan, and deciding to amend, freeze, merge or terminate it
- Setting the benefit formula — match, profit sharing, eligibility, vesting schedule
- Deciding to fund the plan and how much the company contributes
- Selecting and monitoring the fiduciaries you appoint — including the 3(16), the 3(38) and the trustee
That last one is the one sponsors miss. Delegation is itself a fiduciary act. You are judged on whether you chose prudently and whether you monitored afterward — which is a far narrower exposure than running the plan yourself, but it never reaches zero. Anyone who tells you it does is selling something.
Questions we get asked
Yes, and in a full-scope arrangement it usually should be. The 402(a) appointment carries the overall authority to manage plan operation; the 3(16) appointment carries reporting and disclosure. Splitting them across two providers is how responsibility for a missed deadline ends up belonging to nobody.
It moves the selection and monitoring of investments to the manager, which is the largest part of it. It does not remove your duty to have prudently selected that manager and to monitor them afterward. You trade day-to-day investment decisions for an oversight obligation.
Yes. ERISA 403(a) requires plan assets to be held in trust by one or more named or appointed trustees, with limited exceptions such as certain insurance contracts. What varies is whether that trustee is discretionary or directed.
No. Preparing a return and signing it are different acts with different consequences. Read who signs on your last filing — if it is one of your own officers, the responsibility is still inside your building.
Then the statutory default applies and the plan sponsor is the administrator. Many sponsors are surprised to learn they have held the role for years. It is fixed by amendment, not by an agreement with a vendor.
