The Texas Medigap “No Birthday Rule” Trap: What It Means If You Want to Switch (2026)

Texas has no Medigap “birthday rule,” so outside your one-time 6-month Medigap Open Enrollment Period — and a short list of federal guaranteed-issue situations — switching a Medicare Supplement plan in Texas usually means going through medical underwriting. That means the new carrier can review your health history and turn you down, charge you more, or make you wait for a pre-existing condition. A growing number of states (California, Oregon, Idaho, Illinois, Nevada, Louisiana, Maryland, and others) give Medigap enrollees an annual “birthday rule” window to change plans without that health review. Texas is not one of them. So in Houston, the timing of when you first buy a Medigap policy carries far more weight than it does for a retiree in Sacramento or Portland.

If you live in Harris County, you know the rhythm of it: every fall the mailbox fills with glossy carrier envelopes, dinner-seminar invitations land for steakhouses near the Galleria, and somewhere in that noise a salesperson promises you can “always switch later” to a better-priced Medicare Supplement plan. For people getting their care at the Texas Medical Center — where a cardiology workup or a cancer follow-up can put a real medical history on paper — “switch later” is the single most expensive assumption you can make in Texas. This guide is a deeper dive on that switching trap: why it exists here, who is most exposed, the narrow situations where you can still move without underwriting, and how to time the whole thing. If you are brand new to the topic, start with our plain-English guide to what Medigap is and our breakdown of Plan G vs. Plan N in Houston, then come back here for the timing rules.

What is the “birthday rule,” and why doesn’t Texas have one?

A Medigap “birthday rule” is a state law that gives existing Medicare Supplement policyholders a short window around their birthday each year to switch to another Medigap plan without medical underwriting — meaning the carrier cannot review their health to deny or surcharge them. It is a state-created consumer protection layered on top of federal Medigap rules. The catch is that it exists in only a minority of states, and even there the rules are narrow.

As of 2026, a handful of states have adopted some form of an annual birthday-rule or continuous-guaranteed-issue switching window — commonly cited examples include California, Oregon, Idaho, Illinois, Nevada, Louisiana, Maryland, Oklahoma, and Kentucky. The specifics vary a lot from state to state. Some let you switch to any carrier; others restrict you to your current carrier or its affiliate. Most only let you move to a plan with equal or lesser benefits, not richer ones. The window length differs too — anywhere from about 30 to 60-plus days. The common thread is simple: in those states, a Medigap enrollee gets an annual chance to shop without a health review.

Texas has neither a birthday rule nor an annual guaranteed-issue window. The Texas Department of Insurance is clear that outside your federal open-enrollment period or a specific guaranteed-issue situation, a company can use medical underwriting when you apply for a Medicare Supplement policy. There is no statewide annual reset that lets a healthy-or-not Texan shop plans every year without a health review. That is the entire reason this article exists: in Texas, the protection is front-loaded into one window early in your Medicare life, and there is no broad safety net waiting for you afterward.

State birthday-rule details (window length, carrier restrictions, equal-or-lesser limits) differ by state and can change. This table is illustrative of the structural difference, not a substitute for each state’s current statute. Sources: Texas Department of Insurance; medicareresources.org birthday-rule overview.

To make the contrast concrete, here is how a few birthday-rule states are commonly described — alongside Texas, which has no equivalent. Note how even among birthday-rule states the rules differ on who you can switch to and how long the window lasts.

Birthday-rule mechanics vary by state and are subject to change; window lengths and carrier restrictions are summarized in general terms here. Texas appears for contrast only and has no birthday rule. Source: medicareresources.org birthday-rule overview; individual state insurance departments.

Your one-time 6-month window: the only blanket no-underwriting period in Texas

Because Texas has no annual do-over, your Medigap Open Enrollment Period (OEP) is the most valuable window you will ever get for a Medicare Supplement policy. It is a one-time, six-month period that starts automatically the first month you are both 65 or older and enrolled in Medicare Part B. During it, any company selling Medigap in Texas must sell you any policy it offers, cannot turn you down for health reasons, cannot charge you more because of your health history, and cannot make you wait for coverage (with a limited pre-existing-condition exception if you did not have prior creditable coverage). This is your one guaranteed-issue right that applies to every plan, no triggering event required.

A few details that trip up Houston shoppers, and that matter even more here than elsewhere because there is no second chance:

• The window is keyed to your Part B effective date, not just your 65th birthday. If you stayed on employer coverage past 65 and delayed Part B, your 6-month Medigap OEP does not begin until your Part B actually starts.
• It is once-in-a-lifetime for the age-65 trigger. It does not reset annually and it does not come back. (People who get Medicare before 65 due to disability generally get another Medigap OEP when they turn 65.)
• It is not the same as the Medicare Annual Enrollment Period (October 15 – December 7) you hear about every fall. That period is for Part D and Medicare Advantage — it does not give you guaranteed-issue Medigap.

To map your own dates and the larger picture of how the parts fit together, see our Medicare overview and our Medicare Supplement plans page, then let us confirm exactly when your window opens.

What medical underwriting actually means when you try to switch

Medical underwriting is the process where an insurer reviews your health before deciding whether to issue you a policy, at what price, and with what conditions. During your 6-month OEP or a guaranteed-issue situation, underwriting is off the table. Any other time in Texas, when you apply to switch Medigap plans, the new carrier can underwrite you — and that changes everything about whether the switch is even possible.

Here is what a carrier can typically do when you apply outside a protected window:

• Ask detailed health questions. The application can ask about diagnoses, hospitalizations, surgeries, medications, and pending procedures. Some carriers also use prescription-history and medical databases to verify your answers.
• Decline you outright. If your health history falls outside the carrier’s guidelines, it can simply refuse to issue the new policy. You are then left on your current plan.
• Charge a higher rate (or a health-based surcharge). Some carriers will offer a policy but at a rated-up premium based on your health.
• Impose a pre-existing-condition waiting period. A new policy can delay coverage for a condition you were treated for before the policy started — up to six months under federal limits — if you did not have prior creditable coverage to offset it.

The crucial point for Texans: you do not get a guaranteed answer when you apply to switch. You are asking the new carrier to take you, and it can say no. If it does, you keep the plan you already have — which is fine if you are happy with it, but a problem if you were switching to escape a rising premium. The chart below shows what a Houston applicant faces in each scenario.

Federal guaranteed-issue rights that still protect Texans

Even though Texas has no birthday rule, federal law still hands you guaranteed-issue (GI) rights in a specific set of situations — and those apply in Houston just like everywhere else. When a GI right is triggered, carriers must sell you certain Medigap plans, cannot use your health to deny or surcharge you, and cannot impose a pre-existing-condition waiting period. The catch is that each GI right is tied to a triggering event and a tight clock: generally you can apply as early as 60 days before your old coverage ends and no later than 63 days after it ends.

The most common federal GI situations that protect Texans include:

• You lose employer or union (retiree) group coverage that was paying after Medicare. When that coverage ends, you typically get a GI right to buy certain Medigap plans.
• Your Medicare Advantage or PACE plan leaves your area, stops serving Harris County, or you move out of its service area.
• Your Medigap insurer goes bankrupt or becomes insolvent, or your coverage otherwise ends through no fault of your own.
• Your plan misled you or broke the rules — for example, the company materially misrepresented the policy or did not follow Medicare’s rules.
• You are in a Medicare Advantage “trial right” period (covered in the next section).

Two important limits. First, GI rights usually let you buy only certain Medigap plans (often Plans A, B, D, G, K, or L, depending on the situation and when you became eligible), not necessarily every letter on the market. Second, a GI right is not the same as freely “switching.” It is triggered by losing coverage you did not choose to lose — it is a safety net for disruption, not a tool for annual comparison shopping. The table below lays out the main GI situations and their standard windows.

Exact plan eligibility under each GI right depends on your situation and your Medicare-eligibility date; people first eligible on or after January 1, 2020, generally cannot buy Plan C or F. Source: Medicare.gov, “Guaranteed issue rights (Medigap).”

It helps to picture how few of these doors stay open at once. The diagram below sorts your no-underwriting routes in Texas into the one blanket window (your OEP) versus the event-triggered GI rights — and shows that everything outside them lands in underwriting.

The Medicare Advantage trial right and the Jan 1–Mar 31 window

One federal guaranteed-issue right deserves its own section because it is the closest thing Texas has to a built-in escape hatch — the Medicare Advantage “trial right.” If you are new to Medicare and you choose a Medicare Advantage plan for the first time, you generally have 12 months to change your mind, drop that plan, return to Original Medicare, and buy a Medigap policy with guaranteed issue — no underwriting. The same kind of trial right applies if you dropped a Medigap policy to try Medicare Advantage for the first time and want to go back within a year (you can generally return to the Medigap policy you had before).

The mechanics: you must apply for the Medigap policy within 63 days of your Medicare Advantage coverage ending, and the whole thing has to happen inside that first 12-month window. After month 12, the trial right is gone, and in Texas you are back to underwriting if you later want to move from Advantage to a supplement. This is exactly why we tell Houston clients not to treat “I’ll just switch to Medigap later” as a guarantee — once your first year on Advantage passes, “later” can mean a health review.

People often confuse the trial right with the Medicare Advantage Open Enrollment Period (January 1 – March 31). They are not the same:

• The MA Open Enrollment Period (Jan 1–Mar 31) lets someone already in a Medicare Advantage plan switch to a different Advantage plan or drop back to Original Medicare (and pick up a Part D plan). It does not, by itself, give you guaranteed-issue Medigap. If you use it to return to Original Medicare but you are past your trial right, a Medigap application in Texas can still be underwritten.
• The trial right is the piece that adds guaranteed-issue Medigap — but only inside your first 12 months on your first Advantage plan.

So the two can line up (using the Jan 1–Mar 31 window to leave Advantage while still inside your trial year preserves guaranteed-issue Medigap), or they can leave you exposed (using it after month 12 sends you to underwriting). If you are weighing the two coverage paths in the first place, our Medicare Advantage page walks through the trade-offs, and we will check your trial-right clock before you make a move.

Who in Houston is most at risk of the switching trap?

The trap does not hit everyone equally. The Texans most exposed are the ones who picked a plan or a path early, then assumed they could change course freely later. In our Harris County appointments, a few profiles come up again and again:

• The “I’ll switch when it gets expensive” buyer. Someone who took an attained-age Plan G at 65 expecting to jump carriers at 75 when the premium climbs — only to find that, by 75, a cardiac history or a cancer screening makes the new carrier underwrite and decline.
• The first-time Advantage enrollee past month 12. Someone who chose Medicare Advantage at 65, used the care, and now — at 67 — wants the broader access of Original Medicare + Medigap, but is outside the trial right and has developed conditions that complicate underwriting.
• The retiree who let employer coverage lapse without acting. A GI right from losing retiree coverage is powerful, but it expires 63 days after the coverage ends. Miss that clock and you are back to underwriting.
• The healthy 65-year-old who skipped Medigap entirely. Going without a supplement is a legitimate choice — but if you change your mind years later in Texas, you re-enter through underwriting, not your long-gone OEP.

The common thread: every one of these situations was avoidable with a clear-eyed decision during the protected window, or a careful read of the GI calendar. The chart below shows, in rough terms, how the share of people who can clear underwriting tends to shrink as health histories accumulate with age — the very reason “switch later” gets riskier the longer you wait in Texas.

How to time a switch — and what happens if you guess wrong

Because Texas gives you no annual reset, timing is the whole game. Here is the practical sequence we use with Houston and Harris County clients who want to change a Medicare Supplement plan after their OEP has closed:

1. Check for a guaranteed-issue trigger first. Before anyone fills out a health application, we look for an active GI right — losing employer coverage, a plan leaving Harris County, a trial-right clock still running. If one applies, we time the application inside the 63-day window so underwriting never enters the picture.
2. If there is no GI trigger, treat the switch as conditional. Outside a protected window, a Texas switch is an application, not a right. We line up the new carrier’s underwriting questions, confirm whether your health and medications are likely to clear that carrier’s guidelines, and only then apply.
3. Keep your current coverage until the new policy is issued. Never cancel the old Medigap (or end other coverage) on the assumption you will be approved. Approval comes first, cancellation second.
4. Mind the calendar around Advantage. If a switch involves leaving Medicare Advantage, we check your trial-right status and whether the January 1 – March 31 MA Open Enrollment Period helps or simply returns you to Original Medicare without guaranteed-issue Medigap.

What happens if you guess wrong? If you apply outside a protected window and the carrier declines you, you stay on your existing plan. That is not a catastrophe if your current coverage is solid — but it is a real problem if you were trying to escape a steep premium increase, because you are now stuck paying it. If you guessed wrong on a GI clock (say, you let the 63-day window after losing employer coverage lapse), the guaranteed-issue door closes and you re-enter through underwriting. None of this is fatal, but all of it is avoidable with the calendar in front of you before you act.

Comparing carriers when benefits are identical

Here is the fact that reframes the whole “switch later” temptation: within a given plan letter, Medigap benefits are identical by federal law. A Plan G from one company covers exactly what a Plan G from another company covers. So when people talk about switching to a “better” Medicare Supplement plan, they are almost never talking about better coverage — they are talking about a lower premium, a different pricing method, or a carrier with a calmer rate-increase history. That distinction matters in Texas, where chasing a lower premium through a switch can run straight into underwriting. If you want the full benefit-by-benefit picture, our Plan G vs. Plan N comparison breaks it down.

Because the coverage is fixed, the smartest move is to compare carefully during your protected window rather than betting on a future switch. When we compare Texas carriers for a Houston client, we look at:

• Premium and pricing method. Texas allows community-rated, issue-age-rated, and attained-age-rated policies. An attained-age policy can look lower at 65 but climb with age; an issue-age policy holds a flatter age path. The carrier that looks cheaper today may not be the one that ages well.
• Rate-increase history. A carrier’s track record of premium increases tells you more about your long-run cost than its first-year quote.
• Service and stability. How the carrier handles claims and how long it has filed Medigap rates in Texas.
• The right letter for you. Plan G and Plan N dominate today’s choices for people newly eligible after 2020. If you want lower premiums in exchange for a higher up-front deductible, ask about the high-deductible Medigap option.

This is exactly the work we do at the kitchen table for Bellaire, Pasadena, The Heights, Spring, and the rest of Harris County. We are licensed in Texas, we know which carriers file competitive Medigap rates here, and — most relevant to this article — we help you get the decision right while underwriting is off the table, so you are far less likely to ever need a risky switch. When you are ready, contact us and we will map your dates and your options together.

Frequently asked questions

Wise Insurance Agency is a licensed insurance agency in the State of Texas. The information here is general guidance and not a substitute for plan-specific advice. We do not offer every plan available in your area. Any information we provide is limited to those plans we do offer in your area. Please contact Medicare.gov, 1-800-MEDICARE, or your local State Health Insurance Assistance Program (SHIP) to get information on all of your options. Medigap birthday-rule provisions, guaranteed-issue rights, pricing methods, and the standardized benefits within each letter are set by federal law, individual state law, and individual carriers; 2026 Medicare figures reflect CMS data as published as of the date this article was written. State birthday-rule details differ by state and can change. Verify current rules and rates with the Texas Department of Insurance, CMS, or a licensed agent before making any election.