Why Hire A Third Party Administrator (TPA)?
AUTHOR
Henry DeSpain | APA, QPA, ERPA, Partner | With over 30 years in the retirement plan industry, Henry has been a driving force in our company growth and culture. Since joining the firm in 1994, he has specialized in defined benefit plan services, earning long-standing client relationships and recognition as a trusted consultant and speaker for financial advisors.
Why Your Business Needs a Retirement Plan Consulting Firm
Business owners in the 10 to 50 employee range often arrive at the same crossroads when it comes to their company retirement plan. The plan exists, contributions go in each year, and nothing catastrophic has happened. So the question becomes: do we really need a specialist running this?
Sometimes the answer comes in the form of a payroll provider offering to handle plan administration as an add-on service. Sometimes it’s a business owner who is simply confident enough in their financial instincts to manage things in-house. Both paths feel reasonable. Neither one is.
Administering a qualified retirement plan is a regulatory discipline. The rules are specific, the deadlines are real, and the consequences of getting things wrong range from expensive to severe. For businesses in this size range, particularly those with profitable ownership, the stakes on both sides of the equation matter: the downside of a compliance failure and the upside of a plan that’s actually designed to serve the people running the business.
This post covers what third-party plan administration actually involves, why a payroll provider is not a substitute, what can go wrong when administration falls short, and what the opportunity looks like when it goes right.
What a TPA Actually Does
A third-party administrator, or TPA, is a firm that specializes in the design, compliance, and ongoing administration of qualified retirement plans under ERISA and the Internal Revenue Code. For a 401(k) or profit sharing plan, that work includes:
Plan design and document drafting, including the formal plan document that specifies how contributions are calculated, who is eligible, when vesting occurs, and what allocation method applies. This document is a legal instrument. Errors in it have consequences.
Annual nondiscrimination testing, including the ADP and ACP tests for 401(k) deferrals, coverage testing under IRC Section 410(b), and top-heavy testing under Section 416. These tests must be run each year against the actual participant census, and failing them triggers corrective obligations.
Contribution calculations, particularly for plans using more complex allocation methods such as safe harbor, new comparability profit sharing, or integrated formulas. These are not back-of-envelope calculations. They require the plan document, the participant census, and an understanding of how the IRS evaluates the results.
Form 5500 preparation and filing. This is the annual report every qualified plan must file with the Department of Labor and IRS. Late or inaccurate filings carry per-day penalties.
Compliance with regulatory changes. SECURE 2.0 alone introduced dozens of changes affecting catch-up contributions, mandatory auto-enrollment, long-term part-time employee eligibility, and Roth contribution requirements. Plans must be amended when the rules change, and those amendments must be adopted on time.
Participant vesting tracking, distribution processing, and loan administration all carry their own procedural and compliance requirements.
This is the work of a credentialed specialist. It is not a byproduct of running payroll.
Why Payroll Providers Are Not a Substitute
Payroll platforms have made significant investments in retirement plan features over the past decade. Some offer plan documents, contribution remittance, and basic recordkeeping. A few partner with third-party providers to offer more. All of them market these services in ways that can suggest they cover the full scope of plan administration.
They do not.
The critical gap is compliance expertise. A payroll provider can calculate withholding and remit contributions on the schedule you tell them to use. What they are generally not equipped to do is design a plan that serves your specific business goals, run the full battery of nondiscrimination tests against your actual census, identify when a plan design is producing suboptimal outcomes for the owner, or flag a compliance issue before it becomes a problem.
The plan document sitting in a payroll provider’s system is often a prototype document with limited customization. The testing, when it happens at all, may be surface-level and performed after contributions are already in accounts. If a corrective contribution or refund is required, you may not find out about it until your CPA asks a question during tax season.
For a straightforward plan with a stable workforce and modest contributions, the exposure may stay manageable for years. But the moment the plan becomes more complex, through growth, a profitable year, the addition of key employees, or an owner who wants to maximize their own retirement savings, the gaps in payroll-based administration become consequential.
What Can Go Wrong
The failure modes in plan administration are worth understanding specifically, because they tend to be invisible until they’re not.
Coverage and nondiscrimination failures are the most common. The ADP test compares the deferral rates of highly compensated employees against those of non-highly compensated employees. If the ratio falls outside the permitted range, the plan fails. Corrective distributions to highly compensated employees must be processed within a specific deadline, and those distributions are taxable income. Missing the deadline triggers a 10% excise tax. Repeated failures can prompt IRS scrutiny.
Top-heavy failures occur when key employees hold more than 60% of plan assets. When a plan is top-heavy, minimum contributions must be made to non-key employees. If those contributions aren’t made, the plan is out of compliance.
Late or missed Form 5500 filings carry penalties of $250 per day up to $150,000 under DOL penalty authority, with additional IRS penalties on top of that.
Plan document failures occur when the document doesn’t reflect the plan’s actual operation, or when required amendments aren’t adopted on time. Operating a plan inconsistently with its written terms is itself a compliance failure under ERISA.
Distribution and loan errors, particularly improper hardship distributions or loans that don’t meet the plan’s requirements, can cause a distribution to be treated as taxable and subject to early withdrawal penalties.
At the most serious end, a plan that repeatedly fails compliance requirements or is operated without regard to its legal terms can lose its tax-qualified status. When that happens, all participant account balances become immediately taxable, and the employer’s past deductions are subject to recapture by the IRS. For a profitable small business, that’s a financially material event.
None of these failures announce themselves in advance. They surface when someone looks closely, which is either your TPA doing their job proactively or the IRS doing theirs.
The Opportunity Side: What a Well-Designed Plan Can Do
The compliance obligations are reason enough to work with a specialized TPA. But for business owners in a profitable 10 to 50 employee company, the opportunity side of the equation is where the conversation gets more interesting.
A retirement plan designed around your specific business goals, your demographics, and your tax situation can do significantly more than keep you compliant. It can serve as one of the most efficient tools you have for reducing taxable income and building wealth.
The 401(k) profit sharing plans available to businesses today include allocation methods such as new comparability that allow employer contributions to be directed more heavily toward owners and key employees, within IRS rules, while keeping the cost of staff contributions predictable. And for owners who want to go further, adding a cash balance or defined benefit plan alongside the 401(k) opens contribution levels that a 401(k) alone cannot reach.
The following case study illustrates what that can look like in practice.
Case Study: A Central Valley Law Firm
Consider a law firm based in California’s Central Valley. Three partners, two staff attorneys, and three paralegals. The firm generates approximately $15 million in revenue annually. The partners range in age from 47 to 63 and have been focused on building the practice for most of their careers. Retirement savings have not kept pace with the business’s success.
The firm currently offers a 401(k) with a modest employer match. Everyone is eligible and contributing, but the partners are each limited to $72,000 in total annual contributions under the Section 415 defined contribution limit for 2026, and the two oldest partners, ages 58 and 63, can reach $80,000 and $83,250 respectively including catch-up provisions. That’s meaningful, but the partners want to do more given where they are in their careers.
Their CPA raises a question: is the current plan structured to maximize what the partners can contribute? The answer, after a plan design review with Nydia, is no.
Here is what the restructured plan looks like.
The firm adopts a combination DB/DC structure: a cash balance plan layered on top of the existing 401(k) with a new comparability profit sharing component. Each element has a specific role.
The 401(k) with Safe Harbor nonelective contribution: The firm contributes 3% of compensation to all eligible employees as a Safe Harbor nonelective contribution. This satisfies the ADP/ACP nondiscrimination testing requirements, counts toward the new comparability gateway minimum, and satisfies the top-heavy minimum for the 401(k) plan. Partners can maximize their own 401(k) deferrals of $24,500 each (the 2026 limit), plus catch-up contributions where applicable.
The new comparability profit sharing component: On top of the Safe Harbor contribution, the firm makes additional profit sharing contributions allocated using new comparability. Cross-testing confirms that the allocation, which directs a higher percentage to the older partners and a smaller percentage to the younger staff, produces comparable projected retirement benefits when evaluated as Equivalent Benefit Accrual Rates. The 3% Safe Harbor contribution satisfies the gateway minimum for the new comparability testing, so no additional gateway contribution is required for staff.
The cash balance plan: This is where the most significant numbers appear. A cash balance plan is a defined benefit plan that credits each participant with a stated annual contribution (the “pay credit”) and a guaranteed interest credit. The benefit is expressed as a hypothetical account balance, similar to a 401(k), but it’s a defined benefit structure, which means it has its own contribution limit entirely separate from the Section 415 defined contribution limit.
For the 63-year-old partner, the actuarially determined cash balance contribution approaches $275,000 for the year. For the 58-year-old, it’s approximately $190,000. For the 47-year-old, it’s approximately $95,000. Staff attorneys and paralegals receive a modest cash balance credit, proportionate to their compensation and tenure, which in combination with their 401(k) benefits makes the firm’s overall retirement offering genuinely competitive for recruiting and retention.
The numbers across the full structure, combining 401(k) deferrals, profit sharing contributions, and cash balance credits, look like this for the partners:
- The 63-year-old partner: total annual retirement contribution approaching $360,000.
- The 58-year-old partner: total annual retirement contribution approaching $275,000.
- The 47-year-old partner: total annual retirement contribution approaching $175,000.
Every dollar contributed is tax-deductible to the firm. In California, where the combined federal and state marginal rate for top earners can exceed 50%, the tax impact of those deductions is material. A $275,000 deductible contribution doesn’t cost $275,000 in after-tax terms. At a combined marginal rate of 50%, it costs roughly $137,500 in forgone after-tax dollars, while the full $275,000 goes to work in a tax-deferred retirement account.
The staff cost, covering the Safe Harbor contribution, the new comparability profit sharing minimum, and the cash balance credits for five non-partner employees, totals approximately $85,000 across the full staff. The firm is spending $85,000 in employer contributions to unlock more than $800,000 in total tax-deductible retirement contributions across all three partners in a single year.
That is not an exceptional outcome. For a profitable firm with older partners, this is a straightforward result of proper plan design and competent actuarial administration.
One additional note specific to the Central Valley context: many firms in this region haven’t historically had access to plan design expertise at this level without going through advisors who work primarily with large plans. The partners in this scenario had been told for years that their 401(k) was “set up correctly.” It was compliant. It was not optimized. Those are different things.
What the Plan Requires to Work
A combination structure like this doesn’t administer itself. The cash balance plan requires annual actuarial certification, which is why in-house actuarial capability at the TPA level matters. Form 5500 must be filed for each plan. The cash balance plan requires a Schedule SB, the actuarial information schedule, which must be signed by an Enrolled Actuary.
Testing for the 401(k) and profit sharing components must be run against the actual census each year, before contributions are funded. The cash balance contribution amounts are determined actuarially based on participant ages, the plan’s target benefit formula, and the IRS-prescribed interest rate assumptions.
The plan document for the cash balance plan must specify the pay credit formula and the interest crediting rate. Changing those terms requires a formal amendment. The combination plan structure must be coordinated so that the defined benefit and defined contribution components satisfy the combined plan nondiscrimination rules under IRC Section 401(a)(4).
This is not work a payroll provider can perform. It requires credentialed plan administrators, an Enrolled Actuary, and a team that runs these calculations regularly enough to catch issues before they become problems.
At Nydia, our actuarial and administration services include in-house Enrolled Actuaries and credentialed plan administrators who work through exactly this kind of design and ongoing compliance work. We design the plan before contributions are made, run the testing proactively, and coordinate the full picture so that what the partners contribute each year is both legally sound and strategically positioned.
Is This Right for Your Business?
The Central Valley law firm in this example is not unusual. Professional practices, closely held businesses, and owner-operated companies across a wide range of industries can benefit from this kind of design review when the conditions are right: profitable operations, owners who are 45 or older and want to accelerate savings, and a workforce that is younger on average than the ownership group.
The businesses that have the most to gain are often the ones running the most basic plan designs, not because anyone made a poor decision when the plan was set up, but because no one has revisited the design as the business matured.
If your business has been in a 401(k) for several years and no one has reviewed the allocation method, the contribution formula, or whether a cash balance component makes sense given where you are in your career, that review is worth having. The answer might confirm that your current structure is already working well. It might also reveal a material planning gap.
Frequently Asked Questions
What does a third-party administrator do for a retirement plan?
A TPA handles the design, compliance testing, government reporting, and ongoing administration of qualified retirement plans. This includes running annual nondiscrimination tests, preparing and filing Form 5500, calculating contribution allocations, maintaining the plan document, and ensuring the plan stays current with regulatory changes. This work requires specific credentials and expertise that payroll providers and general financial services firms typically do not have.
Can my payroll provider administer our 401(k) plan?
Payroll providers can handle contribution remittance and basic recordkeeping, but most are not equipped to perform the full scope of qualified plan administration. The nondiscrimination testing, plan design analysis, Form 5500 preparation, actuarial work for defined benefit components, and regulatory compliance functions require credentialed retirement plan specialists. For straightforward plans with modest activity, the gap may not surface immediately. For plans with complex designs or profitable ownership, the exposure can be significant.
What happens if a retirement plan fails nondiscrimination testing?
The plan must take corrective action, typically by either returning excess contributions to highly compensated employees or making additional contributions to non-highly compensated employees. Corrections must be completed within IRS deadlines. Missing those deadlines triggers excise taxes. Repeated or uncorrected failures can result in plan disqualification, which causes all participant account balances to become immediately taxable and past deductions to be subject to IRS recapture.
What is a cash balance plan and how does it differ from a 401(k)?
A cash balance plan is a type of defined benefit plan that credits each participant with an annual pay credit and a guaranteed interest credit, expressed as a hypothetical account balance. Unlike a 401(k), it has its own contribution limit separate from the Section 415 defined contribution limit, which means it can be layered on top of a 401(k) to allow significantly higher total annual contributions. For older business owners in high tax brackets, the combination of a 401(k) and a cash balance plan is one of the most powerful tax-deferred savings structures available.
How much can a business owner contribute across a 401(k) and cash balance plan combined?
The answer depends on the owner’s age, compensation, and the plan’s actuarially determined benefit formula. Total contributions combining a 401(k) and cash balance plan can range from well over $100,000 for owners in their late forties to several hundred thousand dollars annually for owners approaching retirement age. Every dollar contributed is generally tax-deductible to the business.
Who needs an Enrolled Actuary for their retirement plan?
Any plan with a defined benefit component, including cash balance plans, requires an Enrolled Actuary to certify the annual funding. The Schedule SB attached to the plan’s Form 5500 must be signed by an Enrolled Actuary. This is a legal requirement, not optional. TPAs with in-house Enrolled Actuaries can perform this work directly; those without them must coordinate with an outside actuary, which adds time and cost.
When should a business review its retirement plan design?
Immediately following any material change to the business: revenue growth, new partners or owners, significant hiring or turnover, or approaching retirement for key principals. Even absent those triggers, a design review every two to three years is reasonable practice. Plans that were set up correctly at inception may no longer reflect the business’s current demographics, goals, or regulatory environment. Compliance and optimization are two different standards, and a plan can satisfy the first while falling well short of the second.
