Highly Compensated Employee 401(k) Rules: What Executives Need to Know (2026)

Most executives assume they can defer $24,500 into their 401(k) every year — end of story. Then February arrives, and a check shows up with a letter explaining that the plan failed nondiscrimination testing and a portion of their contributions is being returned. Taxable. With earnings.

This is the HCE problem. Once you cross the compensation threshold for "highly compensated employee" status, your 401(k) contributions are subject to limits the IRS imposes to prevent qualified plans from disproportionately benefiting top earners. The full employee deferral limit still applies on paper, but whether you actually get to keep all of it depends on what your lower-paid colleagues contribute.

What makes you an HCE

Under IRC § 414(q), you are a highly compensated employee for the 2026 plan year if either of the following is true:¹

• Compensation test: Your compensation from the employer exceeded $160,000 in 2025 (the prior year). This threshold is indexed for inflation annually.
• Ownership test: You were a 5% owner — directly or by family attribution — at any time during 2025 or 2026. Ownership counts regardless of compensation level.

The compensation test catches nearly every named executive officer at a public company. A CFO earning $600K base salary has been an HCE for many years. The ownership test is relevant primarily for founder-executives, family business owners, and executives with meaningful equity in closely held companies.

ADP/ACP testing: why your contributions can be clawed back

Qualified 401(k) plans must pass two annual nondiscrimination tests:²

• Actual Deferral Percentage (ADP) test: Compares the average deferral rate of HCEs against the average deferral rate of non-highly compensated employees (NHCEs). The HCE average generally cannot exceed the NHCE average by more than 2 percentage points (or 125% of the NHCE rate under the alternative test).
• Actual Contribution Percentage (ACP) test: Applies the same math to employer matching contributions and employee after-tax contributions.

If NHCEs save at a low average rate — common at companies where many hourly or entry-level employees don't contribute — the math caps how much HCEs can actually keep. The plan administrator calculates the NHCE average after year-end and determines whether the plan passed.

When the plan fails testing

A failed test must be corrected within 2.5 months after the plan year ends (by March 15 for calendar-year plans) to avoid a 10% excise tax on the employer.² The most common correction is a corrective distribution to HCEs: the plan refunds excess contributions — adjusted for earnings or losses during the year — back to the affected employees.

For you as the executive:

• The refunded amount is taxable ordinary income in the year distributed, not the year contributed.
• You will receive a Form 1099-R in January for the refund amount.
• The 10% early withdrawal penalty does not apply to corrective distributions — but ordinary income tax does.
• Any employer match attributed to the excess contributions may also be forfeited.

In a bad testing year, an executive who contributed the full $24,500 might receive a $5,000–$10,000 refund. That check arrives after you've already arranged your tax planning around the full deferral, increasing your taxable income unexpectedly.

Safe harbor 401(k) plans: how companies avoid testing entirely

Companies that want to guarantee executives can keep the full deferral often adopt a safe harbor 401(k) design. A plan qualifies for safe harbor status — and is automatically deemed to pass ADP/ACP testing — if the employer makes either:³

• A nonelective contribution of 3% of compensation to all eligible employees regardless of whether they contribute, or
• A matching contribution of at least 100% of the first 3% of deferrals plus 50% of the next 2% (the traditional safe harbor match).

If your plan uses a safe harbor design, you generally don't face ADP/ACP testing failure. If you're unsure whether your plan is safe harbor, check the Summary Plan Description (SPD) or ask your plan administrator — it will say so explicitly.

The 2026 Roth catch-up requirement

Starting with SECURE 2.0 Act § 603, employees age 50 or older who earned more than $145,000 in FICA wages from the plan sponsor in the prior year must direct any catch-up contributions to the Roth source — they cannot be made on a pre-tax basis.⁴

For 2026, this means: if your 2025 W-2 wages from your employer exceeded $145,000, your $8,000 catch-up contribution (or $11,250 if ages 60–63) must go into a Roth 401(k) account. Plans without a Roth option that want to allow catch-ups for these employees must add a Roth feature.

Practically, this is a tax timing shift rather than a limit reduction — the catch-up still happens, it just goes into Roth. After-tax dollars go in; tax-free growth and distributions come out. For executives who expect high income in retirement (stacked NQDC distributions, Social Security, portfolio income), forced Roth treatment may actually be favorable long-term.

2026 contribution limits at a glance

What executives do when the 401(k) doesn't stretch far enough

For a CFO earning $1.2M annually, maxing the 401(k) at $24,500 defers about 2% of compensation. Even with employer match, qualified plan limits are a small fraction of what high-earners can benefit from deferring. After ensuring you keep all the ERISA-protected 401(k) space you're entitled to, there are three primary overflow vehicles:

1. Non-Qualified Deferred Compensation (NQDC)

The primary tool for senior executives. No IRS contribution cap — the plan document sets limits (often 50–100% of eligible pay). Pre-tax deferral, tax-deferred growth, ordinary income at distribution. The tradeoff is creditor exposure and distribution inflexibility under § 409A. See our NQDC vs. 401(k) guide for the full allocation framework, and the NQDC Deferral Calculator for the tax math on your specific situation.

2. Mega backdoor Roth (if the plan allows after-tax contributions)

Some 401(k) plans permit after-tax (non-Roth) contributions beyond the $24,500 deferral limit — up to the §415(c) ceiling of $72,000. Combined with an in-plan Roth conversion, this strategy can push $35,000–$47,500 in additional Roth dollars into the plan annually. The plan must explicitly permit both after-tax contributions and in-service conversions. Many large-cap employer plans do; many mid-market plans don't. See our Mega Backdoor Roth guide for mechanics and plan document requirements.

3. Backdoor Roth IRA

The direct Roth IRA income phase-out applies at $165,000 (single) / $246,000 (married) for 2026. Executives above these thresholds use the backdoor approach: contribute $7,500 to a traditional IRA (non-deductible), then convert to Roth. The pro-rata rule applies if you have pre-tax IRA balances — a common complication for executives who rolled prior 401(k)s to an IRA. See our Roth Conversion Planning guide for the mechanics and IRMAA timing.

The HCE planning sequence

1. Capture the full employer match. A 50% or 100% match is the highest guaranteed return available — never leave it on the table due to ADP testing risk. The match itself is the employer's contribution and doesn't count against your deferral limit.
2. Max the employee deferral ($24,500 + catch-up if eligible). Even if a refund is possible, the full-year tax deferral and compounding benefit of keeping the contributions through the year are worth it. Factor the potential refund into Q4 estimated tax planning rather than under-contributing.
3. Check whether your plan allows after-tax contributions. If yes, explore mega backdoor Roth up to the §415(c) limit of $72,000.
4. Evaluate NQDC deferral. After maxing ERISA-protected space, NQDC is typically the most tax-efficient vehicle for large-scale executive deferral — but only if you're comfortable with the employer's financial health and the distribution schedule you elect.
5. Fund a backdoor Roth IRA annually. $7,500 ($8,500 at 50+) in Roth dollars is small relative to executive income, but tax-free growth compounds powerfully over 15–20 years. Establishes 5-year seasoning clock early.
6. If ages 60–63: use the super catch-up. SECURE 2.0 § 109 allows a $11,250 catch-up (vs. the normal $8,000) exclusively for participants ages 60, 61, 62, or 63 — a higher limit that resets when you turn 64. This is often overlooked by executives and their advisors.

1. IRC § 414(q) — highly compensated employee definition; 5% ownership test and compensation threshold. IRS Retirement Plans Definitions. IRS Notice 2025-67 sets the 2026 HCE compensation threshold at $160,000.
2. IRC § 401(k)(3) (ADP test); IRC § 401(m)(2) (ACP test); Treas. Reg. § 1.401(k)-2; Treas. Reg. § 1.401(m)-2. IRS correction framework: IRS 401(k) Fix-It Guide — ADP/ACP Testing.
3. IRC § 401(k)(12) (safe harbor 401(k) design); Treas. Reg. § 1.401(k)-3. IRS ADP/ACP Fix-It Guide. Safe harbor plans are deemed to satisfy ADP testing automatically.
4. SECURE 2.0 Act § 603 (IRC § 414(v)(7)) — Roth catch-up requirement for participants earning >$145,000 in prior-year FICA wages from the sponsoring employer. Final regulations (T.D. 10024, October 2025) apply to plan years beginning after December 31, 2026; good-faith implementation permitted for 2026. IRS Final Regulations — Roth Catch-Up.
5. IRS Notice 2025-67 — 2026 retirement plan limits: employee deferral $24,500; catch-up 50+ $8,000; super catch-up 60–63 $11,250 (SECURE 2.0 § 109); §415(c) total $72,000; HCE threshold $160,000. IRS Newsroom — 2026 401(k) limits. Cross-checked: Fidelity 2026 contribution limits.

All limits verified against IRS Notice 2025-67 (October 2025). SECURE 2.0 provisions per the statute and IRS final regulations. Values current for 2026 plan year.