401(k) nondiscrimination testing—a guide for plan sponsors and other fiduciaries

If there’s any single element that makes America’s workplace retirement plan saving system work, it’s the tax advantages the IRS provides. In return for these advantages, plan sponsors are obligated to ensure that their qualified plans are benefitting employees at every level. Here’s a brief look at the nondiscrimination tests designed to prove that plans aren’t just benefitting the highly compensated—and the penalties plan sponsors can pay if they get a failing grade.

Defining the target group

Nondiscrimination tests for 401(k) plans are primarily concerned with a certain group of employees—highly compensated employees (HCEs)—and whether they’re receiving an unfair share of a plan’s benefits, rights, and features.  

As determined by Section 415 of the Internal Revenue Code (IRC), HCEs are employees who meet one or both of the following criteria:

  • “Five-percent owners”—individuals holding 5% or more of the business they worked for in the previous or current year, or
  • Employees whose compensation in the previous year, referred to as the look-back year, is above the limit set by the IRS. That amount is $130,000 for the look-back years of 2020 and 2021.

These income thresholds are indexed by the IRS and can increase each year. And although it might go without saying, plan participants who don’t meet these criteria are considered non-highly compensated employees, or NHCEs.

The actual deferral percentage (ADP) and actual contribution percentage (ACP) tests look for discrimination by comparing the average deferrals and contributions of your HCEs with the averages of NHCEs.


ADP and ACP tests

Purpose: To preserve an equitable spread in the funding of HCEs’ and NHCEs’ accounts, the ADP test measures how much participants are deferring into their accounts—either on a pretax basis or into a Roth account—and is specified in IRC Section 401(k). The ACP test includes these same deferrals, as well participants’ after-tax deferrals1 and employer contributions. The ADP and ACP tests are specified under IRC Sections 401(k) and 401(m), respectively.


ADP test

Average deferral of NHCEs – average deferral of HCEs

ACP test

Average employer contribution and after-tax participant deferral of NHCEs – average employer contribution and after-tax participant deferral of NHCEs 

Required relationships between NHCE and HCE deferral/contribution percentages

 Percentage among NHCEs

Maximum allowable percentages for HCEs

2% or less

2 times the NHCE percentage

2% to 8%

2.00 percentage points above NHCEs

Over 8%

1.25 percentage points above NHCEs

What happens if a plan fails these tests?

A plan sponsor has two options for correcting an ADP or ACP failure:

  • Return contributions and associated earnings to certain HCEs, which is the most common approach.
  • Make either a qualified nonelective contribution or qualified matching contribution to NHCEs’ accounts, which can be quite expensive.

If a sponsor chooses to return the contributions and earnings to HCEs, they must distribute the amounts no more than 12 months after the close of the plan year. In fact, it’s wise to get it done earlier, since the IRS levies a 10% excise tax on any refund made two and a half months or longer after the plan year ends, with an extension allowed only for plans with an eligible automatic enrollment arrangement.


Top-heavy test

Purpose: To ensure that, over time, key employees don’t end up owning a disproportionately large share of the plan’s assets. Maximum ownership for key employees, as dictated by IRC Section 416, is 60%.

Key employees: As defined by the IRS, key employees are one or more of the following:

  • Officers of the business whose look-back-year earnings are above a certain limit. This limit was $180,000 for 2019 and $185,000 for 2020.
  • Employees owning more than 5% of the business by which they’re employed.
  • Employees owning more than 1% of the business they work for and earning more than $150,000.


Top heavy test

Account balances for all key employees ÷ account balances of all participants

What happens if a plan fails the test?

If over 60% of assets are held by key employees (which is far more likely with smaller plans), the plan sponsor can avoid penalties if the plan clears two subsequent hurdles:

  • The employer must have contributed at least 3% of salary to the accounts of all non-key employees over the entire plan year being tested. This can include employer matching contributions.
  •  If the plan uses a cliff-vesting formula, it must call for no more than three years of service. If it uses graded vesting, the limit is six years.

If these conditions aren’t met, the plan is disqualified by the IRS, triggering potential tax problems for both the participants and the plan sponsor. Sponsors can find relief by working through the IRS’s Employee Plans Compliance Resolution System (EPCRS), Self-Correction Program, and Voluntary Correction Program to correct top-heavy failures and rectify any setbacks to participants. 


Deferral limit test

Purpose: To ensure participants’ pretax and Roth deferrals don’t exceed limits set annually by the IRS and appearing in IRC Section 402(g). The 2021 IRS limit is $19,500, with an additional catch-up limit of $6,500 for participants age 50 and older.


Deferral limit test

Each participant’s total calendar-year elective deferrals – IRS annual limit

What happens if a plan fails the test?

Any excess deferrals (plus any earnings on them) must be returned to the appropriate participants by April 15 of the following year. This triggers additional income taxes for the participants involved.

Plan sponsors who don’t distribute their excess deferrals by the April 15 deadline may be subject to disqualification, causing even more tax liability for participants. Sponsors who miss the deadline can seek a remedy through the EPCRS.


Plan limit tests

Purpose: To ensure that limits set by the plan (rather than the government) are adhered to; these can include deferral limits for HCEs and NHCEs, as well as matching contributions.


Plan deferral limit test

Participant’s annual contribution – plan’s HCE or NHCE deferral limit

Matching contribution test

Participant’s matching contribution – plan’s matching contribution limit

What happens if a plan fails the test?

The plan sponsor can correct the problem themselves according to EPCRS rules. This involves distributing the excess deferral amounts and any earnings to the appropriate participants by the end of the next plan year. Taxes on these distributions are due the year they’re received.


Annual addition limitations test

Purpose: To keep the total of employee and employer contributions for each participant within yearly IRS limits, as prescribed in IRC Section 415(c); for 2021, the limit is the lesser of $58,000 or 100% of compensation. Catch-up contributions, loan repayments, and rollovers into a participant’s account are excluded from the test.


Annual addition limitations test

Participant’s total contributions (deferrals and employer contributions, including any forfeiture re-allocations)­ – allowable maximum total contribution (smaller of yearly dollar limit or 100% of earnings) 

What happens if a plan fails the test?

If the limit is exceeded due to participant deferrals, both the excess deferral amount and any attached earnings must be refunded, which is a taxable event. Excess employer contributions and attached earnings must also be removed from the participant’s account and deposited in the plan’s forfeiture account.

Many plans follow EOCRS rules in determining the hierarchy for returning contributions. Those that don’t must state the correction process in the plan document.

The real test—a plan that benefits all employees

One of the fundamental tenets of qualified retirement plans is that they can’t favor participants who make more over those who make less. Yearly nondiscrimination and compliance testing is a handy tool for detecting any potential problems in this area. More important, it’s an incentive to offer a plan that appeals to every employee.

By building your plans on timely and accurate data, strategic plan design, and a clear set of goals that encompasses the whole workforce, you can pass your tests consistently and provide opportunity for all.


1 These after-tax amounts are not Roth contributions, but are those made by participants who have reached their pretax/Roth limit and whose plan allows them to contribute more.

This is not intended to be an exhaustive review of fiduciary responsibilities of ERISA Section 404(c). It highlights key issues that plan fiduciaries must be aware of; in particular, those required to obtain relief under that section. John Hancock is not in a position to provide you with legal advice concerning your plan or your role as plan fiduciary, and the information included in this booklet should not be taken as such. If legal advice or other expert assistance is required, please consult your legal counsel.