A 401(k) for Your Practice Starts With Decisions You Make This Fall
If you want a retirement plan running in your practice on January 1, the work happens now. The paperwork, the plan design, and the employee notices all have deadlines that land in the fall, and missing them costs you a full year.
That is the practical reason to read this in September. The better reason is that at a small practice, plan design decides how much of the money ends up with you and how much goes to your team. Most owners I meet inherited a plan someone sold them years ago and have never looked at the design since. It is usually doing something other than what they think it is doing.
Start with who the plan is actually for
Before anything else, answer this honestly. Are you setting up a plan so you can defer meaningful income and cut your tax bill? Are you doing it to keep good hygienists and assistants from leaving? Or both?
There is no wrong answer. But the answer drives every other decision, and owners who skip this question end up with a plan that costs real money and does not accomplish the thing they wanted. If the goal is your own savings, the design work is about clearing testing hurdles so you can max out. If the goal is retention, the design work is about making the benefit visible and valuable to people earning far less than you. Those are different plans.
Safe harbor is the decision everything else hangs on
A standard 401(k) has to pass annual nondiscrimination testing. The test compares what the owners and highly paid employees defer against what everyone else defers. If your staff does not participate much, your own contributions get capped, and you find out in March when the plan sends part of your money back to you as a taxable refund.
A safe harbor plan sidesteps that. You commit to a required employer contribution that vests immediately or close to it, and in exchange the plan automatically passes the deferral and match tests and the top heavy minimum.
For most practices, this is the whole ballgame. A dental office with eight employees where the owner earns several times what anyone else earns will almost never pass testing on its own. Safe harbor is what makes the plan work for the person paying for it.
Match or nonelective changes who gets your money
Safe harbor comes in two basic forms and the difference matters more than people expect.
A safe harbor match only pays employees who put their own money in. If half your team does not participate, you do not write them a check. That makes the match cheaper in a practice with low participation, and it rewards the people who are actually saving.
A nonelective contribution goes to every eligible employee whether they defer or not. It costs more up front, but the number is predictable, it satisfies the top heavy requirement cleanly, and it pairs well with a profit sharing formula if you later want to weight contributions toward the owner. Under current rules a match based plan requires an annual employee notice while a nonelective plan generally does not, which is a small administrative difference that matters to the deadlines below.
If your practice has strong participation, the match usually wins on cost. If participation is low and you want a plan that behaves the same way every year, the nonelective is easier to live with.
The employees you did not count are in the plan
Eligibility rules are a design lever, and they are where practices get surprised. Long term part time employees who work at least 500 hours in two consecutive years have to be allowed to defer. In a dental or veterinary practice that means the part time hygienist and the front desk person working three days a week are likely in the plan whether you planned for them or not.
Plans established recently also have to automatically enroll new employees unless an exception applies. Auto enrollment is not a bad thing. It lifts participation, which helps your testing, and it qualifies for a tax credit. It just needs to be a decision you made rather than something you discover later.
The credits cover more of the first three years than owners expect
For an employer with 50 or fewer employees, the startup credit covers 100% of qualified plan startup costs up to $5,000 a year for the first three years. Adding auto enrollment adds $500 a year for three years. There is also a credit for the employer contributions themselves, up to $1,000 per employee earning under $100,000, at 100% in the first two years and then stepping down to 75%, 50%, and 25% over the following three.1
For a practice with a dozen employees, that combination often covers most of the administrative cost and a large share of the contributions in the early years. It does not make the plan free. The employer contribution is still real money leaving the practice, and after year five the credits are gone and the contribution is not. Run the math on year six before you commit, not just year one.
Someone has to be responsible for the investments
When you sponsor a plan you become a fiduciary. That is a real legal responsibility, and it does not disappear because you hired a payroll company to run it. You can hand the investment piece to a firm that accepts that role in writing, which most practices should do. What stays with you is choosing that firm and checking periodically that they are doing the job.
This is the part owners tend to gloss over, and it is the part that creates liability years later. Get it in writing and keep the file.
Sometimes the answer is not yet
If your practice is three years old, cash flow is tight, and you have four employees, a 401(k) may be the wrong tool right now. A SEP or a SIMPLE may fit better, or the money may be better spent paying down practice debt. A plan you have to freeze in two years is worse than no plan at all.
I would rather tell you to wait than sell you something you will resent funding.
The dates that matter this fall
For a calendar year plan starting January 1, 2027, a match based safe harbor notice has to reach your employees between 30 and 90 days before the plan year begins, which puts the window between early October and December 2, 2026.2 If you are converting an existing plan to a match based safe harbor, the amendment has to be adopted before the plan year starts, so by December 31, 2026.3
If you want a brand new safe harbor plan running in the current year instead, the plan's first year has to be at least three months long, which makes October 1 the adoption deadline for a calendar year plan.3 That one has already passed for 2026, which is exactly why this conversation belongs in the fall.
Nonelective safe harbor deadlines run later and give you more room, which is one more reason the match versus nonelective decision is worth having early rather than in December.
The part that has nothing to do with the plan
A retirement plan is one piece of a larger picture. How you pay yourself, how your entity is structured, what you are saving outside the practice, and what you eventually want the practice to be worth all connect to this decision. A plan designed in isolation tends to solve for the wrong thing.
If you are thinking about starting a plan for next year, or you have one and have not looked at the design since you signed it, this fall is when to look. Let's talk.
References
1. Instructions for Form 8881, Credit for Small Employer Pension Plan Startup Costs, Auto-Enrollment, and Military Spouse Participation, Internal Revenue Service. irs.gov
2. Fixing Common Plan Mistakes: Failure to Provide a Safe Harbor 401(k) Plan Notice, Internal Revenue Service. irs.gov
3. Mid-Year Changes to Safe Harbor Plans or Safe Harbor Notices, Internal Revenue Service, including SECURE Act amendment deadline changes. irs.gov
Disclosures
This material is educational and general in nature. Retirement plan rules, deadlines, and tax credit amounts change and depend on the specific facts of your business. Nothing here is tax or legal advice. Coordinate any plan decision with your tax professional and your third party administrator before acting.