If your company sponsors a 401(k) plan, there is a good chance someone within your organization is acting as a plan fiduciary, even if they do not realize it.

For many small and mid-sized businesses, fiduciary responsibility falls on business owners, HR leaders, finance teams, or retirement committees that may not have formal retirement plan expertise. Yet under ERISA, fiduciaries are expected to make decisions that are in the best interests of plan participants.

The good news is that being a fiduciary does not require predicting market performance or becoming an expert in the retirement industry. It requires following a prudent process, understanding your responsibilities, and maintaining appropriate oversight.

At Basic Capital, we believe fiduciary responsibility should be understandable, not intimidating. This guide explains what a plan fiduciary is, what responsibilities come with the role, and how common fiduciary structures such as 3(16), 3(21), and 3(38) services fit into retirement plan governance.

What Is a Plan Fiduciary?

Under ERISA, a fiduciary is anyone who exercises discretionary authority or control over the management of a retirement plan or its assets.

In practical terms, a fiduciary is someone responsible for making decisions that affect the retirement plan and its participants.

Common fiduciary responsibilities include:

• Selecting and monitoring service providers

• Reviewing investment options

• Evaluating retirement plan fees

• Ensuring compliance processes are followed

• Making decisions in the best interests of participants

Importantly, fiduciary status is based on actions rather than job titles.

Someone can become a fiduciary by making retirement plan decisions, even if "fiduciary" is not part of their official role.

What Are a Fiduciary's Core Responsibilities?

While ERISA contains extensive fiduciary requirements, most responsibilities fall into a few broad categories.

Acting in Participants' Best Interests

Fiduciaries must prioritize participants and beneficiaries when making retirement plan decisions.

This means decisions should be guided by:

• Participant outcomes

• Reasonable fees

• Prudent oversight

• Appropriate service provider selection

Following a Prudent Process

ERISA generally focuses on process rather than perfection.

Fiduciaries are expected to:

• Gather information

• Evaluate alternatives

• Document decisions

• Monitor outcomes

A well-documented process is often one of the strongest protections available to plan sponsors.

Monitoring Providers and Investments

Selecting a provider or investment menu is not a one-time event.

Fiduciaries are expected to periodically review:

• Service provider performance

• Investment performance

• Fees

• Participant outcomes

• Compliance processes

At Basic Capital, we often remind employers that fiduciary responsibility is an ongoing obligation rather than a one-time decision.

Understanding the Different Fiduciary Roles

One of the most confusing aspects of retirement plan governance is understanding the different fiduciary designations.

Many employers hear terms such as 3(16), 3(21), and 3(38) without fully understanding what responsibilities each role actually covers.

What Is a 3(16) Fiduciary?

A 3(16) fiduciary is responsible for many of the plan's administrative functions.

These responsibilities may include:

• Maintaining plan documents

• Managing participant notices

• Overseeing eligibility administration

• Coordinating compliance-related processes

• Supporting certain reporting requirements

A 3(16) fiduciary helps manage administrative responsibilities, but employers should carefully understand which duties are delegated and which remain with the plan sponsor.

What Is a 3(21) Fiduciary?

A 3(21) fiduciary provides investment advice and recommendations.

Under a 3(21) arrangement:

• The advisor recommends investments

• The employer retains final decision-making authority

• Fiduciary responsibility is shared

Many employers appreciate the guidance a 3(21) fiduciary provides while maintaining direct control over investment decisions.

What Is a 3(38) Fiduciary?

A 3(38) fiduciary serves as an investment manager with discretionary authority.

Under a 3(38) arrangement:

• The investment manager selects investments

• The investment manager monitors investments

• The investment manager may replace funds when necessary

• The employer delegates day-to-day investment decision-making authority

For many employers, this structure can reduce the administrative burden associated with ongoing investment oversight.

However, employers still maintain responsibility for prudently selecting and monitoring the 3(38) provider itself.

Comparing 3(16), 3(21), and 3(38) Services

Understanding these distinctions can help employers better evaluate retirement plan service providers and governance structures.

Common Fiduciary Misconceptions

"My Recordkeeper Is the Fiduciary"

Many employers assume the recordkeeper automatically assumes fiduciary responsibility.

In reality, recordkeepers often provide administrative services but may not serve as fiduciaries for investment decisions or plan governance.

"We Have an Advisor, So We're Protected"

Working with an advisor can be valuable, but fiduciary responsibility does not disappear simply because an advisor is involved.

Employers should understand:

• Which services are being provided

• Which responsibilities remain internal

• How decisions are documented

"Fiduciaries Are Responsible for Investment Performance"

Fiduciaries are generally responsible for maintaining a prudent investment review process, not guaranteeing investment results.

Market fluctuations alone do not create fiduciary liability.

Common Fiduciary Risks Employers Overlook

Some of the most common fiduciary challenges involve:

• Failure to benchmark fees

• Inadequate documentation

• Limited investment reviews

• Unclear provider oversight

• Missed compliance deadlines

• Poor governance processes

Many of these issues can be addressed through stronger documentation and recurring review procedures.

Employers looking to strengthen retirement plan governance may also find our 10 Common Fiduciary Mistakes in 401(k) Oversight and How to Fix Them guide helpful.

Building a Stronger Fiduciary Process

A strong fiduciary process often includes:

Regular Investment Reviews

Review:

• Performance

• Fees

• Investment lineup structure

• Participant utilization

Fee Benchmarking

Periodically evaluate:

• Provider fees

• Investment expenses

• Advisory compensation

Meeting Documentation

Maintain records of:

• Provider evaluations

• Investment reviews

• Committee meetings

• Key decisions

Provider Oversight

Regularly assess:

• Service quality

• Compliance support

• Fiduciary services

• Participant experience

At Basic Capital, we believe strong fiduciary governance starts with visibility and consistency.

Why Modern Retirement Platforms Matter

As retirement plans become more sophisticated, employers increasingly need tools that support better governance and oversight.

Modern retirement platforms can help simplify:

• Compliance tracking

• Documentation

• Provider oversight

• Participant engagement

• Reporting visibility

At Basic Capital, we believe retirement plans should make fiduciary oversight easier by improving transparency and reducing administrative complexity.

Companies evaluating retirement plan modernization can also explore our For Employers resources to learn how modern retirement infrastructure supports compliance, governance, and employee engagement.

The Bottom Line

Being a plan fiduciary does not mean knowing everything about retirement plans.

It means understanding your responsibilities, maintaining a prudent process, and consistently acting in the best interests of participants.

Whether your plan uses 3(16), 3(21), or 3(38) fiduciary services, employers should understand exactly who is responsible for what and how those responsibilities are being managed.

At Basic Capital, we believe stronger fiduciary oversight begins with greater transparency, better documentation, and a retirement plan structure that supports long-term success.

Ready to see how a modern retirement platform supports fiduciary governance and retirement plan administration? Get started with Basic Capital to learn how we help employers simplify plan management and support better retirement outcomes.