Medicare Supplement Underwriting: A Field Guide for Agents
Medicare Supplement underwriting is the carrier's health review of a Medigap applicant outside open enrollment or a guaranteed-issue right, and agents protect clients by knowing which situation applies before quoting and never cancelling existing coverage until the new policy is approved.
Quick answer:
Know the path. Every case is open enrollment, a federal guaranteed-issue right, a state rule or full underwriting.
Rate increases don't create a federal right to switch. State rules and underwriting decide who can move.
MA plan exits do. Members whose MA plan leaves their area generally get a federal guaranteed-issue right to certain Medigap plans for a limited window, if they return to Original Medicare.
Pre-qualify with the carrier's actual application and prescription review, not gut feel.
Never cancel old coverage until the new policy is approved and kept through the free look.
AEP is here, and my AEP 2027 playbook covers the season. Med Supp questions come with it: rate letters, plan exits and clients asking about Original Medicare.
Agents who only write MA tend to be scared of underwriting. They don't need to be. Underwriting isn't a mystery. It's a process, written down by the carrier and the regulators, and this guide walks through it.
When underwriting applies and when it doesn't
Before you quote anything, answer one question: which path is this client on? Check in this order.
Is the client in their Medigap open enrollment period? If yes, no medical underwriting.
Do they have a federal guaranteed-issue right? If yes, the carrier can't deny them one of the plans the right covers.
Does their state give them an extra right? Birthday, anniversary or year-round rules.
None of the above? Then it's an underwritten case, and you prepare it like one.
Skip this and you'll either underwrite a client who didn't need it or promise a switch they can't get.
Medigap open enrollment period
Under federal law, a client gets a one-time, 6-month Medigap open enrollment period. It starts the first month they have Part B and are 65 or older, per Medicare.gov and Social Security Act section 1882(s)(2). During that window, a carrier can't refuse to sell them any Medigap policy it offers and can't charge more for health problems. It doesn't repeat every year.
Two details trip agents up. First, open enrollment doesn't always mean no waiting period. A carrier can exclude a pre-existing condition for up to 6 months unless the client had at least 6 months of continuous creditable coverage, with no break longer than 63 days, per CMS's Choosing a Medigap Policy guide (March 2026 edition). Second, the window is tied to Part B, and once it starts it can't be changed or repeated. For clients delaying Part B while working, read my post on working past 65 and employer coverage.
Under 65 on Medicare because of a disability or ESRD? Federal law generally doesn't require carriers to sell Medigap to people under 65. Some states do, so check the state.
Federal guaranteed-issue rights (including MA plan terminations)
Guaranteed-issue rights are the limited situations where a carrier must sell a Medigap policy, must cover pre-existing conditions and can't charge more for health. CMS's March 2026 guide lists the most common federal situations:
The client's MA plan is leaving Medicare, stops giving care in their area, or they move out of its service area. CMS's current guide also lists a significant change to the plan's network. The right only applies if the client switches to Original Medicare, not to another MA plan.
An employer, retiree or union plan that pays after Medicare is ending.
Their Medigap carrier goes bankrupt, or the Medigap coverage ends through no fault of their own.
Trial rights. They joined an MA plan when first eligible at 65 and want out within the first year, or they dropped a Medigap policy to try MA for the first time and want back within a year.
The MA plan or Medigap carrier broke the rules or misled them.
Notice what's not on the list. A rate increase.
For MA plan exits, know the window. When a plan terminates the client involuntarily, the guaranteed-issue period opens when the client receives the termination notice and closes 63 days after the MA coverage ends, under section 1882(s)(3)(E). The Medigap policy can't start until the MA coverage ends. The plan that's leaving is required to notify the member of these rights, and the client has to send proof of the termination date with the Medigap application. Save that letter.
Know which plans the right covers. Federally, it's a Plan A, B, C or F for clients eligible for Medicare before January 1, 2020, and Plan A, B, D or G for clients new to Medicare on or after that date, sold by a carrier in the client's state (section 1882(s)(3)(C) and (z); CMS guide, pages 17 to 18). The NAIC model regulation that states use as a template also lists Plans K and L, and some states go further. A client who wants Plan N on a guaranteed-issue basis needs a state rule that allows it or has to go through underwriting.
The 2027 MA exits will put many clients in this spot. My playbook for clients whose MA carrier is exiting in 2027 covers the bigger conversation. On the Med Supp side: confirm the right, document it, apply inside the window.
State rules (birthday, anniversary, year-round)
Federal law is the floor. A number of states give residents more, and the rules keep changing. A few examples, each checked against the state's own source:
Birthday rules. California gives existing Medigap policyholders a 60-day window starting on their birthday to move to a plan with equal or lesser benefits, per the California Department of Insurance. Oregon's window runs from 30 days before to 30 days after the birthday, for the same or lesser benefits, per its Division of Financial Regulation.
Anniversary rules. Missouri lets policyholders switch companies within 30 days before or after their policy anniversary if they keep the same plan letter, per the Missouri Department of Insurance.
Year-round rules. New York requires Medigap insurers to accept applications any time of year without health-based denials or pricing, per the New York Department of Financial Services.
The NAIC keeps a state-by-state birthday rule chart (as of May 11, 2026), and it shows rules taking effect as recently as January 2026. Use it as a starting point, then confirm the details with the state insurance department before you tell a client they can move. Massachusetts, Minnesota and Wisconsin also standardize their Medigap plans differently, per the CMS guide.
How the underwriting process works
Outside open enrollment and guaranteed issue, a carrier can deny a policy if the client doesn't meet its medical underwriting requirements, per Medicare.gov. CMS defines medical underwriting as the process a carrier uses to decide, based on medical history, whether to accept the application, whether to add a pre-existing condition waiting period where state law allows, and how much to charge. So it's not always a simple yes or no.
Application health questions
The application is the underwriting. You'll usually see knockout questions first, then conditions, treatment, hospital stays and medications inside specific look-back periods. Some carriers also use a height and weight chart. The questions, look-backs and wording differ by carrier and state.
If the client is in open enrollment or has proof of a guaranteed-issue right, the carrier can't use their medical answers to deny them or change the price, per the CMS guide. Carriers also can't ask about family history or require a genetic test.
Here's the part every agent needs to hear. The client answers every question truthfully and completely, and you never coach an answer. The NAIC model replacement notice warns that leaving out material medical information can give the carrier grounds to deny future claims and refund the premium as if the policy never existed. By then, the old coverage is gone.
Prescription and MIB checks
Read the authorization page of the carrier's application. It tells you what the carrier can pull: prescription history, medical records, a phone interview or a database check. Assume the carrier can see the client's prescription history. A medication tied to a declinable condition can sink an application even when the client says they feel great.
Some carriers also check MIB. MIB runs a database its member insurers use to cross-check applications. A client only has an MIB file if they applied for individually underwritten life or health insurance with a member company in the last 7 years and something of underwriting significance came up. Carriers can't base a decision on the MIB file alone without more investigation, and clients can request their own file once a year at no charge.
Phone interviews and decision timing
Some carriers confirm the application by phone. Some request medical records. Some decide fast. The carrier's guide tells you its process and turnaround.
Plan the dates around it. Medigap coverage generally begins the first of the month after the client applies unless they ask for a different date, per Medicare.gov. Replacing a policy? Plan the overlap using the free-look steps below.
Common decline triggers (and why carriers differ)
Underwriting isn't one rulebook. Each carrier writes its own application and guidelines inside state law, so two carriers can look at the same client and land in different places.
The kinds of things that tend to stop an application:
Recent or pending care: a hospital stay, surgery, or tests that haven't come back yet.
Diagnoses inside the look-back: the conditions named on that carrier's knockout list.
Current treatment for a serious condition.
Prescriptions that point to one of those conditions, even when the condition is "under control."
Build outside the carrier's height and weight chart.
Inconsistencies between the answers, the prescription history and the records.
The fix isn't memorizing anyone's list. Keep a cheat sheet for every carrier you're appointed with, built from that carrier's current underwriting guide and dated "as of." Not from old training books. Guides change, and your sheet should too. If you're not appointed with the Med Supp carriers you need yet, start with my carrier appointments guide.
How to pre-qualify a client without overpromising
Pre-qualifying protects the client from a decline and you from a promise you can't keep. The routine:
Confirm the path. Open enrollment, federal right, state rule or underwritten. Write it down.
Get the full medication list. Drug, dose and what it's for. Pull bottles if you're at the kitchen table.
Walk the carrier's actual application questions, word for word. Not a summary. The real questions, in the real order.
Run the medications against the carrier's guide or prescription tool.
Check the build chart.
Pick a primary carrier and a backup.
Set expectations in plain words. Pre-qualified isn't approved. The carrier decides.
At Brock, partners have an underwriting quoting tool for Med Supp and other lines on our agent resources page. Whatever tool you use, the carrier's own application and guide are the final word.
Simple. Just not easy.
Re-shopping after a rate increase
A rate letter is a service call. Treat it like one.
In most cases, a client has no federal right to switch Medigap policies unless they're in open enrollment or have a guaranteed-issue right, per Medicare.gov. So check the state rule first. If there isn't one, pre-qualify it like any underwritten case.
Then compare the right things:
Same plan letter, same benefits. The premium is the only difference between policies with the same letter from different companies, per the CMS guide. Compare G to G.
How it's priced. Ask whether the policy is community-rated, issue-age-rated or attained-age-rated, and how the premium has moved. The CMS guide suggests those exact questions.
A different plan, if it fits. Some clients are better served by Plan N or a high-deductible option, depending on how they use care and how much risk they're comfortable with. Our 2027 agent strategy post frames Medigap as a risk conversation, and that's the right way to have it.
Waiting periods. If the current policy has been in force 6 months or longer, the replacement can't add new pre-existing waiting periods for similar benefits. Any new benefit can still have a waiting period of up to 6 months, per the CMS guide.
If the client won't pass underwriting, staying put is the right answer. Say so.
And don't turn rate letters into a rewrite machine. The NAIC model application asks agents to list the health policies they've sold the applicant, including ones from the last five years no longer in force. Every replacement should be one you'd defend to the client, the carrier and the state.
Replacement rules and the free-look period
This is where good agents get careless. Follow the order.
Apply while the old policy stays in force. On the application, the client states in writing that the new policy replaces the old one and that they'll cancel it (section 1882(d)(3)(B); CMS guide).
Complete the replacement notice. Under the NAIC model, the agent gives the applicant a notice regarding replacement before the policy is issued. The applicant and the agent sign it, the applicant keeps a copy and the carrier keeps one. The agent also states the reason for the replacement. Your state's version is the one that counts.
Wait for approval and delivery.
Use the free look. Federal law requires at least 30 days after issue to return a Medigap policy for a full refund. CMS describes it as 30 days from when the client gets the new policy. The NAIC notice says it plainly: don't cancel the present policy until the client has the new one and is sure they want to keep it.
Then cancel the old policy. The client will pay both premiums for the month they have both. Once the old policy is cancelled, they can't get it back.
Coming from MA? A carrier can't issue a Medigap policy that starts before the client's MA coverage ends, per the CMS guide and the NAIC model. And Medigap plans sold today don't include drug coverage, so line up a standalone Part D plan so the client isn't left without drug coverage.
Never let a client drop coverage before the new policy is approved. Not to save a month of premium. Not because the carrier "usually" approves this. Never.
Documentation and compliance habits
Good habits keep good business on the books. What I'd keep in every Med Supp file:
The path and the proof. Which path applied and the document behind it: the termination notice, the claim denial or the state rule. Medicare.gov tells clients to keep those letters. Keep a copy too.
The pre-qualification notes. The medication list, the carrier questions you reviewed and the date.
The signed replacement notice and the dates the new policy was approved, delivered and kept, and when the old one ended.
The reason for any replacement. Under the NAIC model, agents must make reasonable efforts to determine that a recommended purchase or replacement is appropriate, and twisting and high-pressure tactics are prohibited.
Your carrier cheat sheets, dated, from the carriers' current guides.
One more note if you turn any of this into client-facing marketing. Med Supp ads may need to be filed with the state for review under section 1882(b)(3) and state law, and the NAIC model prohibits cold lead advertising, meaning marketing that doesn't clearly disclose it's an insurance solicitation and that an agent or insurer will make contact. Nothing can imply you're Medicare or the government. If the piece also markets Medicare Advantage or Part D, CMS's TPMO rules apply too, including the required disclaimer under 42 CFR 422.2267(e)(41), and it goes through your compliance approval. Clients can also get one-on-one counseling from their state's SHIP.
FAQs
Does a Medigap rate increase give my client guaranteed issue?
Not under federal rules. A rate increase isn't one of the federal guaranteed-issue situations. Some states have birthday, anniversary or year-round rules, so check the client's state insurance department before you promise a switch.
Who gets guaranteed issue when an MA plan leaves their area?
Members whose MA plan leaves their service area generally have a federal guaranteed-issue right to certain Medigap plans if they return to Original Medicare. For an involuntary termination, the window opens when they get the notice and closes 63 days after the MA coverage ends. Confirm the plans and timing on Medicare.gov and with the state.
Can a client keep their old Med Supp until the new one is approved?
Yes, and they should. Cancel the old policy only after the new one is approved, in force and kept through the free-look period. They'll pay both premiums for the month they have both.
How long does Med Supp underwriting take?
It varies by carrier. Some decide quickly, while cases that need medical records or a phone interview take longer. Check the carrier's guide for its process and plan the effective date around it.
Do all carriers ask the same health questions?
No. Questions, look-back periods and prescription rules differ by carrier and state, which is why carrier-specific prep matters. Walk the carrier's actual application before you submit.
The Bottom Line
Underwriting isn't the scary part. Guessing is.
Know the path. Pre-qualify with the real application. Document the right. Keep the old policy until the new one is approved and kept. Then go help people.
Want help on a tough underwriting case? Book a call with my team.
