401(k) Roles, Explained: Who's Accountable for What
Running a retirement plan involves more people than you might think and knowing who's responsible for what protects you from liability you didn't know you had. Here's a breakdown of the key roles.
Key takeaways
If you sponsor a 401(k), you're likely already a fiduciary. Fiduciary status attaches the moment you exercise real control over the plan or its assets, and ERISA holds you to a demanding standard once it does.
Delegating a task doesn't delegate the liability. Even when providers handle the work, you remain responsible for selecting and monitoring them.
Each role on your plan team carries a different level of responsibility. Plan administrators and trustees hold fiduciary duties, recordkeepers and TPAs handle operations and compliance, and investment advisors vary depending on whether they serve as a 3(21) or 3(38).
Most problems start in the handoffs. A missed deferral change or a late contribution deposit can become a compliance issue, which is why knowing exactly who owns what matters.
Behind every well-run, competitive 401(k) plan is a team of people and providers, each with distinct roles. The challenge is that plan sponsors sometimes assume their provider is handling something that's actually still on their plate — or vice versa.
Knowing exactly who's responsible for what is the foundation of a healthy, compliant plan. It also helps protect you from liability you likely didn't know you had. Before you can sort out who handles what, it helps to first understand your own role as a plan sponsor. The following questions and answers will help.
Who is accountable for what in 401(k) plan administration? FAQs
Am I automatically a fiduciary?
Probably, and many employers don't realize it until something goes wrong. Fiduciary status is triggered the moment you exercise any real control over the plan or its assets.
The Employee Retirement Income Security Act (ERISA) sets a demanding bar for anyone in the fiduciary role: decisions have to be made purely for the benefit of participants and beneficiaries. Sponsors who overlook this, or who haven't built a support structure around it, take on personal financial exposure they may not know exists.
Do I need to hire outside help to manage my company’s retirement plan?
While you can technically handle plan administration internally, most employers rely on outside professionals for recordkeeping, compliance testing and daily operations.
As the plan sponsor, you retain oversight even when you delegate tasks, making sure the right expertise is in place so nothing falls through the cracks.
If I hire a provider, am I off the hook for fiduciary risk?
Delegating a task doesn't automatically delegate the liability that comes with it. You're still responsible for selecting and monitoring the professionals you hire. That's why understanding each role — and what it does and doesn't cover — matters even if you're not the one performing the work.
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401(k) plan administration roles and responsibilities
It's worth knowing who sits where. Here's how the work typically breaks down across your retirement plan's team.
Plan sponsor. As the plan sponsor, you decide what the plan includes, whether to change it and whether to keep it. Those choices aren't fiduciary duties on their own, but running the plan day to day, based on those choices, is.
Plan administrator. Your plan document names someone to run the operational side of things, and that person or entity is the plan administrator. In this fiduciary position, participants' interests always come first. Because the workload is significant, most companies outsource this role to a third-party professional who can juggle the moving pieces, from testing and filings to fielding employee questions.
Trustee. The trustee holds legal title to the plan's assets and is responsible for overseeing them prudently on behalf of participants. This is one of the clearest fiduciary roles in the plan structure, since it involves direct control over plan assets.
Recordkeeper. The recordkeeper tracks the details — participant balances, contributions, investment elections and transactions. Accurate recordkeeping makes it possible to generate statements, process distributions and stay audit-ready.
Third-party administrator (TPA). A TPA handles a lot of the technical and compliance-heavy lifting, including nondiscrimination testing, Form 5500 preparation and plan document maintenance. TPAs often work alongside recordkeepers, though in some plan structures the same provider may fill both roles.
Investment advisor. Investment advisors help select and monitor the plan's investment lineup. Their level of fiduciary responsibility depends on how their role is structured.
A 3(21) advisor provides recommendations, but the sponsor retains final decision-making authority. A 3(38) investment manager takes on discretionary authority for investment decisions, shifting a major share of that fiduciary responsibility away from the sponsor.
Payroll provider. Since contribution timing, deferral elections and eligibility changes all flow through the payroll provider first, having payroll and plan integration is essential.
Auditor. Plans with more than 100 eligible participants generally require an independent annual audit. The auditor reviews the plan's financial statements and operations to confirm everything lines up with ERISA requirements. It's not a role most sponsors think about until it's required, but it adds another layer of accountability to how the plan is being run.
Most plans involve a mix of these roles, and the lines between them aren't always obvious from the outside. Gaps tend to show up in the handoffs — a task everyone assumed someone else had covered.
Connecting the dots
With ADP in your corner, you don't have to map all of this out on your own. To review your plan's current structure and make sure every role is covered the way it should be, learn more about ADP Retirement Services or call (800) 432-401K today.
ADP, Inc., and its affiliates do not offer investment, tax, or legal advice to individuals. Nothing contained in this article is intended to be, nor should be construed as, particularized advice or a recommendation or suggestion that you take or not take a particular action. Questions about how laws, regulations, guidance, your plan’s provisions, or services available to participants may apply to you should be directed to your plan administrator or legal, tax or financial advisor.
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