Georgia Medicare Secondary Payer (MSP) Rules: A Complete Guide

If you have Medicare in Georgia alongside other coverage, one set of federal rules decides which plan pays first, and getting the order wrong causes denied claims and a lifelong Part B penalty. These are the Medicare Secondary Payer (MSP) rules. They come from the Medicare coordination-of-benefits framework in the Social Security Act (42 U.S.C. 1395y(b)) and its rules at 42 CFR Part 411, and they govern every interaction between Medicare and an employer Group Health Plan (GHP), workers' compensation, no-fault and liability insurance, the Federal Employees Health Benefits (FEHB) program, TRICARE, U.S. Department of Veterans Affairs (VA) coverage, and Georgia Medicaid. Which one applies to you turns on your age, your employer's size, and how you got Medicare.1,2 The who-pays-first mechanics that apply in every state are in our national Medicare coordination of benefits guide; this page adds the Georgia layer, especially the payer-of-last-resort rules for dual-eligibles.

Misunderstanding the MSP rules is one of the most common causes of avoidable Medicare problems in Georgia. A worker at a small employer assumes any job-based coverage lets them delay Part B, when only large-employer coverage does. A retiree leans on COBRA as a bridge and burns through a deadline they did not know was running. A kidney patient with an employer plan is unsure who pays for dialysis. A QMB enrollee is billed for a copay that federal law says the provider must write off. Each of these turns on a specific MSP rule, and this guide walks Georgia families through all of them.

Below: the four core rules, insurer reporting and conditional-payment recovery, how MSP drives the Part B penalty, the COBRA trap, FEHB, TRICARE and VA coordination, Medicaid as payer of last resort for Georgia dual eligibles, worked examples, and a checklist.

The Georgia Medicare Secondary Payer Framework

The Medicare Secondary Payer rules are set in the Social Security Act (42 U.S.C. 1395y(b)) and carried out in the regulations at 42 CFR Part 411. The core principle is simple: in certain defined situations, Medicare pays after other coverage rather than before. Medicare is the secondary payer to (1) certain group health plans based on current employment, (2) workers' compensation insurance, (3) no-fault auto insurance, and (4) liability insurance, which includes auto, slip-and-fall, medical malpractice, and product-liability claims. Two narrower situations round out the list: the federal Black Lung program pays first for care related to black lung disease, and TRICARE pays first for someone on active duty. In every other situation, Medicare pays first, and a coverage type that is not on the list does not displace Medicare.2,1

To keep primary-payer status current, the Centers for Medicare & Medicaid Services (CMS) relies on mandatory insurer reporting from employers and insurers, matched against Medicare's own coverage records. When Medicare pays a bill another payer should have covered, CMS has a right to recover it, which is where conditional payments and Medicare Set-Asides come in later in this guide.2

The 20-Employee Rule: When Your Georgia Employer Plan Pays First

The most important MSP rule for Georgia working seniors is the working-aged 20-employee rule. If a Medicare-entitled beneficiary age 65 or older has coverage from an employer Group Health Plan based on their own or their spouse's current employment, and the employer has 20 or more employees, the GHP pays first and Medicare pays second. If the employer has fewer than 20 employees, Medicare pays first.1

The 20-employee threshold is counted nationwide, not just at your worksite or in Georgia. A Georgia-based law firm with 12 local staff but 25 employees total, including a New York office, has 25 employees for MSP purposes and clears the threshold. A smaller employer can also clear it through a multi-employer group health plan, if at least one participating company has 20 or more employees. "Current employment" means active work, not retirement. Retiree coverage from a former employer, even if it looks identical to the active-employee plan, is not based on current employment, so Medicare pays first and the retiree plan pays second.1

This rule is the gateway to the Part B late-enrollment penalty. A beneficiary with large-employer, current-employment GHP coverage qualifies for the Working Aged Special Enrollment Period, which lets them delay Part B without penalty during active employment and gives them an 8-month window to enroll after that employment ends. A beneficiary without that status, meaning a small-employer plan, retiree coverage, or COBRA, does not get the SEP and must enroll in Part B during their Initial Enrollment Period (IEP) at 65 to avoid the penalty.1,6

If you are weighing whether to keep working and rely on your employer plan instead of enrolling in Part B, this is the single detail that decides it, and it is easy to get wrong. Confirm your employer's nationwide headcount in writing before you lean on the plan.

The 100-Employee Rule for Disability Beneficiaries Under 65

For a Georgia beneficiary under 65 who has Medicare through Social Security Disability Insurance (SSDI), a different threshold applies. If the SSDI beneficiary or a family member has GHP coverage based on current employment and the employer has 100 or more employees, the group health plan pays first and Medicare pays second. Below 100 employees, Medicare generally pays first even during active employment.2,1

The threshold is higher than the working-aged 20-employee figure because Congress chose to limit the cost that being the primary payer places on smaller employers of disabled workers. Like the working-aged count, the 100-employee threshold looks at the employer that sponsors the plan, counted nationwide, not at the individual's own job. A 50-year-old SSDI beneficiary covered under a spouse's family plan at a 200-employee firm has GHP-primary coverage; the same person covered by an 80-employee firm generally does not, and Medicare pays first. The exception worth checking: if that 80-employee firm participates in a multi-employer group health plan in which at least one company has 100 or more employees, the plan is still primary.2,1

The 30-Month ESRD Coordination Period

For a beneficiary with End-Stage Renal Disease (ESRD), an employer Group Health Plan pays first for a 30-month coordination period regardless of employer size. Read the start date carefully, because it is the detail families get wrong: the period always begins on the date the person is first eligible to enroll in Medicare because of ESRD, not the date they actually enroll, so putting off enrollment does not push back the clock. That date is usually the first day of the fourth month of dialysis. After the 30 months, Medicare pays first. The rule also does not depend on anyone still working: it applies to anyone covered by a group health plan on any basis, retirees included.1,3

The ESRD rule is unique because it has no employer-size test. A 50-year-old ESRD patient with coverage from a 5-employee small business still has a primary GHP for the first 30 months. If dialysis begins in March 2025 and ESRD-based Medicare eligibility begins July 1, 2025, the 30-month period runs from July 2025 through December 2027, and Medicare becomes primary effective January 2028. During those 30 months the employer plan pays first for dialysis, transplant evaluation, transplant surgery, post-transplant immunosuppressant drugs, and related care, while Medicare pays second for deductibles, coinsurance, and gaps.3,1

Workers' Compensation, Auto, and Liability: When Those Payers Come First

Medicare is always secondary to workers' compensation, no-fault auto insurance, and liability insurance for the treatment of injuries those payers cover. This rule has no employer-size threshold.1,2

Workers' compensation. Georgia workers' compensation is administered by the Georgia State Board of Workers' Compensation under Georgia law (O.C.G.A. Title 34, Chapter 9). When a Georgia worker of any age is hurt on the job, the employer's workers' comp insurer pays first for care related to the injury, and Medicare pays nothing on that care during the active claim. If the claim is denied, delayed, or disputed, Medicare may pay conditionally so the beneficiary is not stuck, on the condition that Medicare is repaid once the claim pays or settles.2

No-fault auto insurance. Medicare is secondary to no-fault auto coverage for accident-related care. Whether a particular Georgia crash involves no-fault coverage at all depends on the policies in force, so read the auto policy before assuming Medicare pays first.1

Liability insurance. Medicare is secondary to liability insurance for injuries from third-party claims, including auto accidents where another driver is at fault, slip-and-fall, medical malpractice, product liability, and dog bites. When a Georgia beneficiary receives a settlement or judgment that pays for care Medicare already covered, CMS can recover those conditional payments from the proceeds.2,1

Mandatory Insurer Reporting

Under Section 111 of the Medicare, Medicaid, and SCHIP Extension Act of 2007 (MMSEA), group health plans, liability and no-fault insurers, and workers' compensation entities must report coverage information to CMS so Medicare can identify when it should be secondary. The reporting is mandatory and is enforced with financial penalties for non-compliance.2

These reports are how CMS spots primary coverage before Medicare pays. Beneficiaries can update their own coverage information and dispute a determination through Medicare's Benefits Coordination and Recovery Center.2

Conditional Payments, Recovery, and Medicare Set-Asides

When Medicare pays first in a situation where another payer was responsible, CMS issues a recovery demand to get its money back. Under the recovery rules at 42 CFR 411.24, the party that received a primary payment must reimburse Medicare, generally within 60 days, and CMS can pursue a beneficiary, provider, attorney, or insurer. In litigation, CMS may recover double damages.2

Two contractors run this work. The Benefits Coordination & Recovery Center pursues repayment where recovery is sought from the beneficiary, and since October 5, 2015 the Commercial Repayment Center pursues it directly from the liability, no-fault, or workers' compensation payer. The mechanic is the same whichever of those is the primary payer.2

For workers' compensation settlements, and certain liability settlements, that include money for future injury-related care, a Workers' Compensation Medicare Set-Aside Arrangement (WCMSA) allocates part of the settlement to pay for future care Medicare would otherwise cover. Those funds must be spent on related care before Medicare pays. Using a set-aside is the recommended method to protect Medicare's interest; it is not statutorily required, and the amount is set case by case. Because the rules are technical and every allocation is judged on its own facts, a Georgia beneficiary facing a significant workers' comp or liability settlement should consult an attorney who handles these matters before signing.2

How Georgia Medicare Secondary Payer Rules Drive the Part B Penalty

The MSP framework is what makes the Working Aged Special Enrollment Period possible, and that SEP is the most important way to avoid the Part B late-enrollment penalty when you work past 65. The SEP is available only to beneficiaries with primary-payer GHP coverage based on current employment.1,6

A beneficiary at a large employer (20 or more employees) with active coverage has a primary GHP, so Medicare is secondary, Part B can be delayed without penalty, and the 8-month SEP begins when employment ends. A beneficiary at a small employer (fewer than 20) does not have a primary GHP; Medicare is primary even while they are working, the plan is only secondary, and they must enroll in Part B during their IEP at 65. Miss that window and enrollment waits for the General Enrollment Period (January 1 through March 31), with coverage starting the first day of the following month and a penalty of 10 percent for each full 12-month period of delay, lasting as long as they have Part B. The 2026 standard Part B premium is $202.90 per month, so a single 12-month delay adds a $20.29 monthly penalty, for a $223.19 total.7,8,6

"As long as you have Part B" has one Georgia exit worth knowing about. Approval for a Medicare Savings Program activates the State Buy-In under Section 1839(b)(3) of the Social Security Act, which exempts the beneficiary from the Part B late-enrollment surcharge for as long as the MSP enrollment lasts. Georgia MSP applications are processed by the Division of Family and Children Services through Georgia Gateway. So a low-income Georgian carrying a penalty should check MSP eligibility rather than assume the surcharge is permanent.5

This small-employer trap is one of the most common avoidable penalties in Georgia. Before you rely on a job-based plan to delay Part B, confirm your employer's nationwide headcount with human resources in writing, ideally on Form CMS-L564 (Request for Employment Information).1

The COBRA Trap That Costs Georgia Retirees a Lifelong Penalty

The moment you retire, COBRA continuation coverage feels like a safe bridge until you sort out Medicare. For Medicare timing, it is a trap, and the cost lands years later. COBRA is post-employment coverage, so it does not count as coverage based on current employment. If you have Medicare because you are 65 or older or because of a disability, Medicare pays first and COBRA pays second, and COBRA does not extend the Working Aged SEP.1

There is one exception, and it runs the other way. If your Medicare is based on ESRD, COBRA is primary to the extent it overlaps the 30-month ESRD coordination period, so a Georgia kidney patient on COBRA should have claims billed to COBRA first, not Medicare. The exception is about payment order only. The enrollment deadline below is not excepted for anyone.1

The consequences cascade. First, the 8-month SEP clock starts when active employment ends, not when COBRA ends. A retiree who takes 18 months of COBRA after leaving a job at 65 has run out the 8-month window long before COBRA ends, and must then wait for the General Enrollment Period and accept a penalty. Second, because Medicare is primary the whole time, the retiree owes Medicare cost-sharing during the COBRA period, and providers should bill Medicare first. Third, providers who treat COBRA as primary bill in error, claims get denied, and the retiree is left with bills that proper coordination would have prevented.1,6

The fix is straightforward: enroll in Part B at the end of active employment, whether or not COBRA is available. A Georgia beneficiary who is unsure should call GeorgiaCares, the state's free Medicare counseling program run by the Georgia Division of Aging Services, at 1-866-552-4464, option 4, Monday through Friday between 8 a.m. and 5 p.m., before declining Part B in reliance on COBRA.9

FEHB, TRICARE for Life, and VA Coordination

Federal Employees Health Benefits (FEHB). For an active federal employee, FEHB pays first and Medicare is secondary, so the employee may defer Part B without penalty and gets an 8-month SEP when active employment ends. Once retired, if the annuitant or a covered spouse has Medicare, Medicare pays first and FEHB pays second, and many FEHB plans waive their own deductibles, coinsurance, and copayments when Medicare is primary. No FEHB rule requires Part B, so taking it is a personal decision, but declining it at retirement and enrolling later outside a Special Enrollment Period triggers the permanent Part B penalty. Check with the U.S. Office of Personnel Management before declining Part B.10

TRICARE for Life (TFL). TFL is the Medicare-wrap coverage for uniformed services retirees 65 or older, their eligible family members and survivors, and certain former spouses, and you must have both Medicare Part A and Part B to get TFL benefits. The payer order is conditional. If you are not on active duty, Medicare pays first and TRICARE for Life may pay second. If you are on active duty the order reverses, and TRICARE pays first. And if you get care at a military hospital or clinic, or any other federal health care provider, TRICARE pays and Medicare usually does not. This is a critical distinction for Georgia's large military-retiree population.11

Department of Veterans Affairs (VA). VA health care and Medicare do not coordinate the way a primary and secondary insurer do. VA care covers services at VA facilities or VA-authorized care, and Medicare covers care from non-VA providers who accept Medicare. A veteran uses VA coverage for VA care and Medicare for non-VA care and chooses which to use for each visit; the two generally do not pay together on the same claim. One MSP consequence catches Georgia veterans out: VA coverage is not employer coverage for Part B purposes, so it gives you no Part B Special Enrollment Period, and relying on VA care alone while putting off Part B can leave a permanent late-enrollment penalty.12

Medicaid as Payer of Last Resort for Georgia Dual Eligibles

For a Georgia dual eligible, someone with both Medicare and Georgia Medicaid, Georgia Medicaid pays last. Federal law makes Medicaid the payer of last resort: Section 1902(a)(25) of the Social Security Act requires every state plan to take all reasonable measures to identify third parties legally liable for a member's care and to seek reimbursement to the extent of that liability, and 42 CFR 433.139 requires the agency to avoid or recover a payment once a third party's liability is established. So Medicare pays before Georgia Medicaid, and so does any employer plan, workers' compensation carrier, or liability insurer that the rules earlier in this guide put ahead of Medicare. Georgia Medicaid is administered by the Georgia Department of Community Health (DCH).4

How much Medicaid pays depends on the Medicare Savings Program category. A Qualified Medicare Beneficiary (QMB) has Georgia Medicaid pay the Part A and Part B premiums and all Medicare cost-sharing, meaning deductibles, coinsurance, and copays. A Specified Low-Income Medicare Beneficiary (SLMB) or Qualifying Individual (QI) has Georgia Medicaid pay only the Part B premium, and the beneficiary is responsible for cost-sharing; QI is funded from a limited annual allotment granted first-come, first-served, a QI enrollee cannot also have full Medicaid, and QI must be applied for again every year.5 For a full dual, Georgia Medicaid also covers Medicaid-only services Medicare does not, including long-term services and supports at home through the Elderly and Disabled Waiver Program's Community Care Services Program (CCSP) and SOURCE, which serve Georgians who would otherwise need a nursing facility level of care.13

The rule that trips up the most Georgia families is QMB balance billing. Federal law prohibits a provider from billing a QMB enrollee for Medicare cost-sharing; the provider must accept the Medicare-approved amount plus any Medicaid payment as payment in full. If a Georgia QMB is billed for a Medicare copay or deductible, that is improper. File a complaint with DCH Medicaid Member Services at 1-866-211-0950 or call Medicare at 1-800-MEDICARE.5,14

Worked Examples: Georgia MSP Scenarios

The people below are illustrative, and the dollar figures are hypothetical, used to show how the rules play out for typical Georgia situations.

Maria, 66, Savannah: the small-employer GHP trap

Maria works at a 12-employee Savannah accounting firm. She turned 65 in September 2024 and assumed her firm's plan would let her delay Part B without penalty. It did not. Because her employer has fewer than 20 employees, Medicare is primary even during her active employment, and she does not qualify for the Working Aged SEP.1

She did not enroll at 65, and by the time she reached GeorgiaCares in 2026 she had missed her IEP by about 17 months. Her enrollment runs through the General Enrollment Period, with coverage starting the following month, and her one full year of delay produces a 10 percent penalty. Her 2026 monthly cost is $202.90 plus $20.29, or $223.19, and the penalty follows her for life. Her small-employer plan, secondary all along, had left providers billing Medicare first and getting denied because she had no Part B, creating billing disputes on top of the penalty.8,7,6

Patricia, 55, Augusta: the ESRD coordination period

Patricia started dialysis in March 2025 in Augusta after kidney failure related to diabetes. She has employer coverage at a 50-employee firm and is first eligible for Medicare because of ESRD effective July 1, 2025, the fourth month of dialysis. Under the ESRD rule, the 30-month coordination period runs from July 2025 through December 2027, and during it her employer plan pays first regardless of the firm's size.3,1

After December 2027, Medicare becomes primary regardless of whether Patricia is still working. She enrolls in Part B during her IEP so Medicare can pay second during the 30 months and first afterward. Her dialysis, transplant evaluation, eventual transplant, and post-transplant care are covered first by her employer plan for the 30-month window, with Medicare paying second for deductibles and coinsurance.1,3

Charles, 70, Columbus: a workers' compensation claim

Charles, 70, hurt his back at a part-time hardware-store job in Columbus and has Medicare Parts A and B. His employer's workers' compensation insurer pays first for the work-related injury under Georgia law (O.C.G.A. Title 34, Chapter 9), and Medicare pays nothing on that care during the active claim. His unrelated Medicare-covered care, such as diabetes management, continues under normal Medicare rules.1,2

Two years in, Charles settles, with part of the settlement allocated for future back-injury care. That amount goes into a Workers' Compensation Medicare Set-Aside, which he must spend on related care before Medicare pays for it; once exhausted, Medicare pays under normal secondary rules. Without the set-aside, CMS could have challenged the allocation and required more funding, cutting into his settlement.2

Susan, 68, Athens: the COBRA trap

Susan retired from her Athens job at 65 in 2023 from a 200-employee firm, so during active employment she had primary GHP coverage and correctly delayed Part B under the SEP. On retiring, she elected 18 months of COBRA, believing it kept her SEP status. It did not, because COBRA is not coverage based on current employment.1

Her 8-month SEP started when her job ended in 2023 and closed in mid-2024, while she was still on COBRA and assumed she had until it ended. Meanwhile COBRA was secondary to Medicare, so providers who billed it first had claims denied because she had no Part B, and she accumulated bills that proper coordination would have prevented. When COBRA ended in early 2025, she enrolled through the General Enrollment Period with a 10 percent penalty, making her 2026 cost $202.90 plus $20.29, or $223.19, plus the leftover billing disputes.1,8,7,6

Common Georgia MSP Mistakes to Avoid

1. Assuming any employer plan lets you delay Part B. Only a large-employer plan (20 or more employees for working aged, 100 or more for disability) based on current employment supports the SEP; retiree coverage does not.1

2. Believing COBRA extends the SEP or that the clock runs from the end of any coverage. It starts when active employment ends.1

3. Confusing the 30-month ESRD rule with the working-aged or disability rules. The ESRD rule ignores employer size.1

4. Filing with Medicare when workers' compensation, no-fault, or liability insurance is the proper first payer, or signing a settlement without considering a Medicare Set-Aside for future care.2

5. Letting a provider bill a QMB enrollee for Medicare cost-sharing, which federal law prohibits.5

6. Not knowing TRICARE for Life requires Part B, or treating VA coverage like a coordinating insurer. TFL benefits require both Part A and Part B, and VA care and Medicare do not pay together on the same claim.11,12

How to Navigate Georgia Medicare MSP Rules Step by Step

Resources and Where to Turn Next

The checklist above holds across almost every Georgia MSP situation, and the single most damaging trap in it is COBRA, because the 8-month Part B clock starts at retirement, not when COBRA ends.

Learn More

Find personalized help understanding Medicare Secondary Payer rules in Georgia at brevy.com.

The information on Brevy.com is for educational purposes only and is not a substitute for professional legal, financial, or medical advice. Rules vary by state and program and change frequently. Always verify with the relevant agency or a qualified professional. Brevy is not a law firm, financial advisor, or healthcare provider.