Safe Harbor 401(k): How It Works and When It Beats a SIMPLE IRA

A Safe Harbor 401(k) is a plan that automatically passes the IRS Nondiscrimination Tests in exchange for a mandatory employer contribution (which must be immediately vested) and you agree to use either a predetermined set of matching contributions or make a flat 3% contribution to each eligible employee. In return, owners and high-paid employees may defer the full annual deferral limit and avoid having their money clawed-back by the ADP/ACP testing requirements.

In a typical 401(k), if rank-and-file employees only slightly contribute then testing will be able to require owners to withdraw most of their own deferrals. The Safe Harbor eliminates this risk, but guarantees there will be a contribution made to an employee's account.

What is a safe harbor 401(k)?

The design was developed to buy out these tests, because a standard 401(k) runs testing of employee deferrals (ADP) and employer matching (ACP) on a yearly basis. They compare what highly compensated employees have contributed versus all other employees as part of their testing each year, and if there is too great a difference between contributions made by both groups, then the plan has failed and will require money be returned to the owners of that business. The IRS notes that safe harbor plans are not subject to these tests. Nor are those with no additional funding subject to top-heavy rules.^[1] To receive such an exemption, employers fund a set amount and vest it immediately. This is where this particular design fits into small business retirement plan options.

Why do owners choose the safe harbor design?

The purpose of the "Safe Harbor" is to allow owners to use the plan they are paying for. Consider a dental practice in which the owner receives $250,000 and would like to defer all $24,500 allowed by the IRS under 2026, and also, stack employer contributions toward profit sharing up to the $72,000 overall limit.^[2] If there are four employees averaging only 2% deferrals, then, in a plain 401(k) design, the ADP test might limit the amount of deferrals that can be made available to the owner at or near 4% and return any excess amounts back as taxable income. Through making a non-elective contribution of 3% (e.g., $6,000 over a $200,000 staff payroll), it ensures that the owner gets to take advantage of the maximum allowable deferred amount, $24,500, and eliminates any risk of failing an ADP test. These checks pay themselves off fairly quickly when used by owners who are trying to maximize their deferred amounts close to ceilings.

What are the safe harbor 401(k) contribution requirements?

You meet the safe harbor with your selection from one of three formulas, that are defined in Internal Revenue Code Section 401(k)(12), and each formula is immediately vested the moment it hits the account.^[3] The two match methods will not cost you anything for any employee who never defers, while the non-elective method guarantees a contribution on behalf of every eligible employee. This is why it's considered "predictable budget" option. The formulas shown below represent statutory minimums:

In traditional 401(k), a vesting period in a matching contribution means the employer's match vests over several years (and thus an employee may forfeit part of it if they leave prior to full vest). However, safe harbor contributions always vest immediately. There is no "vest" for an employer's safe harbor contribution, as each employer dollar is the employee's property on day one, which mirrors the SIMPLE IRA employer match rules. Therefore, when an employee leaves employment with respect to a plan utilizing safe harbor contributions, he/she/they will lose none of those contributions (as opposed to potentially losing a portion of them under plans using a traditional match).

Is a safe harbor 401(k) worth it versus a SIMPLE IRA?

In most cases for a small team, choosing a safe harbor 401(k) will be an overreaction. While this type of plan eliminates the need to test for compliance with the nondiscrimination rules, it does not eliminate all of the administrative tasks associated with maintaining your own 401(k): each year you are required to file your Form 5500 and hire either a third party recordkeeper or administrator to handle the day-to-day management of your 401(k).^[4] A SIMPLE IRA has none of these requirements. It is merely a two-page IRS form with no Form 5500 and no annual filing. This is one reason that IRS Publication 560 describes it as the low overhead option available to small employers.^[5] The primary ongoing cost of the safe harbor 401(k) is the fee charged by your recordkeeper for managing your account(s), plus the annual Form 5500. As opposed to this model, when you use IRAPilot, we assist you in setting up and administering a SIMPLE IRA without charge. There are no subscription costs and no per-employee charges.

An owner assumes the expense because of the ceiling, and there is a big difference in size:

You can easily identify the "tell" as it relates to owner-heavy deferrals. If you have a small company and are still using a SIMPLE IRA, do not change until one of your owners has maxed out their ability to contribute to a SIMPLE IRA due to the cap on those plans. Once an owner or key employee cannot make additional contributions through a SIMPLE IRA (due to having reached that plan's contribution limit), switch them into a Safe Harbor 401(k) plan. As the Safe Harbor 401(k) has a much larger contribution ceiling than the SIMPLE IRA plan (plus employer contributions), that ceiling is what earns the Form 5500 and the recordkeeper. For a complete comparison of costs, refer back to SIMPLE IRA vs. 401(k).

What are the safe harbor notice and timing rules?

Safe Harbor Status is dependent upon advising employees of the applicable election rules prior to the beginning of a plan year. The Internal Revenue Service (IRS) requires that employers provide a written safe harbor notice to each eligible employee at least 30 days and no more than 90 days prior to the start date of the Plan Year.^[1] This notice will outline which formula(s) apply, and how employees may elect or change their elective deferrals. If this time frame is missed by the employer, it is possible for the employer's Plan to be subject to full ADP and ACP testing for that year, as if it were in a non-safe harbor status. One exception being, under the SECURE Act of 2019 an employer may adopt a 3% nonelective safe harbor, however, such an adoption must occur by no later than thirty (30) days before the end of the plan year. There are no exceptions with respect to providing advance notice for any matching formulas selected under a safe harbor election, therefore it would be prudent for employers to establish their selection of match formulas prior to opening their new plan year.

The Bottom Line

A Safe Harbor 401(k) is a 401(k) that allows owners to trade in their mandatory and immediately vested employer contribution for the automatic passing of the ADP and ACP testing rules. Owners will want this plan if they wish to defer more than the approximately $17,000 SIMPLE IRA limit but are willing to accept Form 5500 and recordkeeping costs as well. If an owner has less than those limits, then a SIMPLE IRA will give them most of the same benefits with far fewer associated expenses. Prioritize price comparisons on both plans prior to making your decision.

This guide is educational and summarizes IRS rules for safe harbor 401(k) plans. It is not investment, legal, or tax advice. Your plan documents and current IRS limits control. Talk to your tax advisor about your business's circumstances.