Open Enrollment Season Starts Now. Here's Your Timeline.

September starts tomorrow.

Which means if open enrollment is still sitting on your someday list, this is the week it moves to the top of it.

Most small businesses treat open enrollment as a November event. Send the packet, collect the forms, done. That timeline works right up until it does not: a rate increase you did not budget for, a notice deadline you blew past, or an employee who signs up for something they did not understand and comes back angry in February.

Here is the actual timeline, working backward from January 1.

Why This Year Deserves Extra Attention

A few things changed for the 2027 plan year that are worth knowing before you look at renewal numbers.

According to the IRS in Revenue Procedure 2026-26, the ACA affordability threshold rises to 10.22% for plan years beginning in 2027, up from 9.96%. That is the first time it has crossed 10%, and it gives applicable large employers slightly more room on employee contributions.

This matters only if you have 50 or more full-time equivalent employees.

Out-of-pocket maximums also jumped. According to the HHS Notice of Benefit and Payment Parameters issued in January 2026, the 2027 limits are $12,000 for self-only coverage and $24,000 for family, up from $10,600 and $21,200. These apply to all non-grandfathered plans regardless of employer size, including fully insured, self-insured, and level-funded.

On the individual side, marketplace open enrollment for 2027 coverage opens November 1, 2026. December 15 is the date that matters in every scenario, since enrolling by then is what starts coverage on January 1. Whether enrollment continues past December 15 is currently unsettled. CMS finalized a rule shortening the window, a federal court vacated it in June 2026, and the appeal is pending. If any of your employees decline your coverage and buy their own, point them to HealthCare.gov for the live deadline rather than relying on last year's dates.

September: Decisions and Numbers

This is your quiet month, and it starts tomorrow. It is also the one that determines whether the rest goes smoothly.

Get your renewal numbers. If you have not received them from your broker or carrier, ask today. You cannot plan a contribution strategy around a number you do not have.\

Decide what you are actually offering. Same plans? New carrier? Changing the employer contribution? Adding or dropping anything? Every one of these decisions has a downstream effect on your communication and your payroll setup, so make them now rather than in October.

Run your contribution math. If you are an applicable large employer, check affordability against the 10.22% threshold using whichever safe harbor you use, and document the calculation. If you are under 50, you are not subject to the employer mandate, but you still want to know whether your contribution is competitive enough to keep people enrolled.

Confirm your eligibility rules still match reality. Waiting periods, hours thresholds, who counts as full time. If you have hired part-timers who crept up in hours, this is when you find out.

Set your enrollment window. Two weeks is standard. Two weeks in a small business where half your team works a non-desk schedule is often not enough. Give yourself three.

Early October: Build the Materials

Draft your communication before you draft the forms. The single biggest open enrollment failure at small businesses is not a compliance miss. It is employees who do not understand what they picked. A one-page summary of what changed, in plain language, does more good than a forty-page carrier packet nobody opens.

Confirm what is changing and say it directly. If premiums went up, say so and say by how much. Employees find out either way. They find out better from you.

Ask your broker for your full notice packet. There is a standard set of annual notices that goes out with enrollment materials, and which ones apply depends on your plan design, your funding arrangement, and your size. Your broker or carrier can usually assemble most of it. Do not assume they did. Ask, and ask specifically which notices apply to your plan.

October 15: The Deadline Most Small Businesses Miss

Write this one down.

Medicare Part D creditable coverage notices must be distributed before October 15.

This one catches small employers constantly, because the assumption is that it only applies to big companies or to businesses with retirees. It does not. According to CMS, this requirement applies to every employer who sponsors prescription drug coverage, regardless of plan size, grandfathered status, or whether the plan is fully insured or self-funded.

The notice tells Medicare-eligible individuals whether your prescription drug coverage is at least as good as Medicare Part D. Technically it goes to Part D eligible individuals who are enrolled or seeking to enroll. Practically, you have no way of knowing who is enrolled in Medicare Part A or B, so the standard advice is to send it to everyone.

CMS publishes model notices in English and Spanish, so you do not have to draft anything. You do have to know your plan's creditable status, which usually comes from your carrier or third-party administrator.

There is no direct penalty on the employer for missing this. The cost lands on your employee, who can face a permanent late enrollment penalty if they go 63 days or more without creditable coverage and cannot prove otherwise. That is a bad thing to be responsible for.

Separately, you owe CMS an online disclosure of your plan's creditable status within 60 days of the start of your plan year. For calendar year plans, that is March 1.

A Note on the CHIP Notice

One that trips up Michigan employers in both directions.

There is a federal notice about premium assistance under Medicaid and CHIP. Michigan does not participate in that program, so Michigan itself does not trigger it.

But the requirement follows where your employees live, not where your business is. If anyone on your team resides in a participating state, and plenty of states participate, you owe them the notice. With remote work as common as it is now, this catches more small Michigan employers than it used to.

The Department of Labor publishes a model notice with a current state list. Most employers just send it to everyone rather than tracking who moved where.

Late October Through November: Run It

Open the window and communicate more than feels necessary. One announcement is not a communication plan. Plan for an opening message, a midpoint reminder, and a final call with 48 hours left.

Hold a session, even a short one. Fifteen minutes where someone explains a deductible, an HSA, and what changed will save you a dozen individual conversations in January.

Meet people where they are. If part of your team does not sit at a computer, an email-only enrollment guarantees you will be chasing signatures. Paper, text, or a stand-up meeting works better.

Track who has not responded. Then follow up individually. Passive enrollment is fine if your plan is set up for it. Assuming silence means agreement is not.

Do not give benefits advice. You can explain how the plan works. You should not tell an employee which option to choose or make predictions about their medical situation. Point them to the carrier or a licensed advisor.

December: Close It Out

Confirm every election is recorded, get elections into payroll before the first January pay period, verify carrier enrollment files, and file your documentation. The most common January headache at a small business is a deduction that does not match what the employee thought they elected.

Also flag the December 15 marketplace date for any employee going that route, since that is what determines January 1 coverage.

What Small Businesses Get Wrong

Treating it as a paperwork exercise. Benefits are usually your second largest people expense after payroll. Rolling them over without a look is an expensive habit.

Waiting on the broker. A good broker handles a lot. They do not run your internal communication, your payroll setup, or your deadline tracking. Those are yours.

Assuming size exempts you. Some rules key off 50 employees. Plenty do not, including the Part D notice and the out-of-pocket limits.

Skipping the year-over-year comparison. If you cannot say what changed and by how much, your employees definitely cannot.

Never asking what people actually want. You may be paying for something nobody values while missing something they would trade for it. A three-question survey costs nothing.

The Bottom Line

Open enrollment is one of the few HR events with a fixed, immovable deadline. January 1 does not move because September got busy.

The businesses that handle it well are not the ones with the best benefits. They are the ones who started in September, communicated clearly, and hit the October 15 date nobody remembers.

Pick one thing off this list and put it on your calendar for next week.

This is general information, not legal or benefits advice. AlphaDog HR Solutions helps businesses run open enrollment, handle compliance notices, and communicate benefits in a way employees actually understand. If open enrollment is currently living in someone's inbox, let's talk.