SERP vs Deferred Compensation Plan vs 401(k) Restoration Plan: An Employer Comparison
SERP vs deferred compensation plan vs 401(k) restoration plan: who funds each, cost, ERISA and 409A treatment, financing and retention for private employers.
In a SERP vs. deferred compensation plan comparison, the key difference is whose money it is: a supplemental executive retirement plan (SERP) is an employer-funded promise of extra retirement benefits, while a voluntary deferred compensation plan lets executives postpone part of their own pay. A 401(k) restoration plan sits between them, giving back the qualified-plan contributions that IRS limits take away.
Many private employers end up with a mix. The right combination depends on how much you want to spend, how tightly you want to tie executives to the company and how much cost uncertainty and administration you are willing to carry. This guide compares the three, plus the Section 162 executive bonus plan that often comes up in the same conversation, from the sponsor's side.
It covers private-employer plans. Your plan documents govern how any arrangement works, so involve ERISA and tax counsel, your recordkeeper and your advisers before choosing a structure.
SERP vs. NQDC vs. restoration plan: the comparison table
The table summarizes the typical case. Individual plans can be designed very differently.
| SERP | Voluntary NQDC plan | 401(k) restoration or excess plan | Section 162 executive bonus plan | |
|---|---|---|---|---|
| Whose money | Employer's | Executive's own deferred pay, sometimes plus employer credits | Employer's, replacing lost qualified-plan contributions | Employer's, paid as current bonus |
| Benefit form | Target benefit (often a formula based on pay and service) or an employer-credited account | Account balance | Account balance | Cash, often used to pay a life insurance premium |
| When the executive pays income tax | At payout | At payout | At payout | When the bonus is paid |
| When the employer deducts | Generally when the executive is taxed (payout) | Generally when the executive is taxed (payout) | Generally when the executive is taxed (payout) | When the bonus is paid |
| ERISA status | Usually a top-hat plan | Top-hat plan | Top-hat plan, or an exempt "excess benefit plan" if it restores only 415 losses | Generally not a retirement plan |
| Section 409A | Generally applies | Applies | Generally applies | Generally not, if paid currently |
| Cost predictability | Low for target-benefit designs | High: employer cost is mainly administration and any credits | Moderate: follows your 401(k) formula | High: fixed bonus |
| Retention effect | Strong if vesting is long | Moderate; stronger with vested employer credits | Moderate, depends on vesting | Weak unless tied to a repayment agreement |
| Administrative burden | Highest | Moderate, mostly outsourced | Moderate | Low |
The deduction timing follows 26 U.S.C. §404(a)(5), which generally delays the employer's deduction for nonqualified deferred compensation until the employee includes it in income. Confirm the treatment of your plans with your advisers.
SERPs: employer-funded and increasingly frozen
A SERP is the classic executive retirement promise. Older designs target a benefit, such as a percentage of final average pay for life, offset by Social Security and qualified-plan benefits. Newer designs often look like an account, with an annual employer credit and a vesting schedule.
SERPs are a powerful retention tool because the value usually grows with tenure and vesting can be long. They are also the most expensive and least predictable option. A target benefit depends on pay growth, interest rates and longevity, and the company carries that risk.
That helps explain the trend. In the 2024 Newport/PLANSPONSOR NQDC survey, 36% of responding companies offered a SERP, down from 48% in 2022, and many SERPs were frozen to new entrants or new benefits. Newport, part of Ascensus, is an NQDC provider. Among large public companies, the GAO found that as of 2017 more than 400 of the S&P 500 offered executive retirement plans to almost 2,300 top executives, with about $13 billion in accumulated benefit promises (GAO-20-70, 2020).
Voluntary NQDC plans: the executive's own money
A voluntary NQDC plan lets eligible executives defer salary and bonus into an unfunded account, usually with notional investment options and a choice of payout dates. The company's direct cost is mostly administration, plus any employer credits and the cost of informal funding.
Sponsors offer these plans mainly for competitiveness and savings capacity. PSCA's 2025 NQDC survey found 85.9% of employers cited a competitive benefits package as a top reason and 56.3% said the plan helps eligible employees accumulate assets. The same survey found 69.8% of eligible executives participated in 2025, an aggregate rate across all eligible executives in the sample.
The catch is that a voluntary plan delivers value only when executives decide to use it. In the 2026 Newport/PLANSPONSOR survey, the most cited barriers to participation were lack of understanding (46%) and irrevocable election rules (27%). For the details of deferral elections, see the 409A deferral election rules, and for how employer money changes the math, see the employer match guide.
Restoration plans and ERISA excess benefit plans
A restoration plan gives executives the qualified-plan benefits they would have received without IRS limits. In 2026, the 401(a)(17) limit caps the pay a 401(k) can count at $360,000, the elective deferral limit is $24,500 and the 415(c) annual additions limit is $72,000 (IRS Notice 2025-67). The IRS is expected to publish 2027 limits in November.
The terms are used loosely, but they mean different things under ERISA:
- Excess benefit plan. ERISA defines an excess benefit plan narrowly as one maintained solely to provide benefits above the IRC 415 limits (29 U.S.C. §1002(36)). An unfunded excess benefit plan is exempt from Title I of ERISA entirely (29 U.S.C. §1003(b)(5)).
- Restoration plan. A plan that also restores contributions lost to 401(a)(17), 402(g) or NQDC deferrals does not fit that narrow definition. It is usually maintained as a top-hat plan, which is exempt from ERISA's participation, vesting, funding and fiduciary rules but still subject to relaxed reporting, claims procedures and enforcement (29 U.S.C. §1101).
Both are generally subject to Section 409A. Many companies fold restoration credits into their voluntary NQDC plan rather than run a separate plan, which simplifies administration and gives executives one account. Plans maintained solely to restore benefits above qualified-plan limits also have their own exception from state source taxation under 4 U.S.C. §114. Counsel should confirm whether yours qualifies.
Section 162 executive bonus plans
A Section 162 executive bonus plan is not deferred compensation. The company pays a bonus, often used to pay premiums on a life insurance policy the executive owns, and deducts it as ordinary compensation. The executive pays income tax now.
Compared with a deferral plan, it offers simplicity and no exposure to the company's credit, and the company gets the deduction immediately. The trade-offs are the reverse: no tax deferral for the executive and little retention value unless the bonus is paired with an agreement to repay it if the executive leaves early. Some companies use it for executives who would not benefit from deferring, or alongside an NQDC plan.
Choosing the right mix for a private company
Most private employers can frame the choice with a short checklist:
- Budget and cost certainty. If you need predictable costs, favor account-based designs (voluntary NQDC with restoration or discretionary credits) over a target-benefit SERP.
- Retention goal. Long vesting on employer money, whether SERP credits or NQDC credits, ties executives to the company. Voluntary deferrals vest immediately and retain only through the payout schedule.
- Fairness with the broad-based plan. A restoration match tells executives they get the same formula as everyone else, without the IRS limits.
- Financing. PSCA's 2025 survey found two-thirds of respondents set assets aside for NQDC obligations, and 90.6% of those use a rabbi trust. In the 2026 Newport/PLANSPONSOR survey, almost 50% used corporate-owned life insurance as the primary vehicle. A rabbi trust does not protect participants in insolvency (see NQDC risks and rabbi trusts).
- Private-company realities. Executives may already hold illiquid company equity, and there is no public credit signal. Clear communication about benefit security matters more.
- Administration. The 2024 Newport/PLANSPONSOR survey found 94% of sponsors outsource NQDC administration. Ask your provider what each structure adds to the workload.
Whatever the mix, voluntary deferral is the part that depends on each executive's decisions, and it is the hardest part to communicate. When you license NQDC Calculator, your deferral limits, payout schedules, employer credits and vesting are configured with you as starting values. Each executive can then model deferrals alongside employer credits privately and see the whole package, including federal and state tax for both paths and employer credit risk. You never see individual inputs or results, and the tool never recommends an election. The plan design best practices guide covers the other design levers.
Frequently asked questions
What is the difference between a SERP and a deferred compensation plan?
A SERP is funded by the employer and promises an extra retirement benefit, often based on pay and service. A voluntary deferred compensation plan holds the executive's own deferred salary and bonus, sometimes with employer credits added. Both are usually unfunded top-hat plans subject to Section 409A.
What is a 401(k) restoration plan?
It is a nonqualified plan that gives executives the 401(k) contributions, usually the match, that IRS limits prevent the qualified plan from providing. In 2026, the 401(a)(17) limit caps countable pay at $360,000. Many companies run restoration credits through their existing NQDC plan.
How is an ERISA excess benefit plan different from a restoration plan?
ERISA defines an excess benefit plan narrowly, as a plan maintained solely to provide benefits above the IRC 415 limits, and an unfunded one is exempt from Title I entirely. A plan that also restores contributions lost to other limits is usually a top-hat plan instead, with relaxed reporting and claims requirements. Have counsel confirm which category your plan falls into.
How does a Section 162 executive bonus plan compare with deferred compensation?
A 162 bonus is taxed to the executive and deducted by the company when paid, so there is no deferral and no credit risk. It is simple to run but offers little retention value unless paired with a repayment agreement. Deferred compensation postpones both the tax and the employer's deduction.
Which is cheaper and simpler to administer?
A voluntary NQDC plan without employer credits usually costs the least, because the money is the executive's own. Restoration credits add a cost that follows your 401(k) formula. A target-benefit SERP is the most expensive and least predictable, which is one reason many SERPs have been frozen.