Medigap Plan G: Why a Therapy Client Owes a Deductible

Last reviewed: October 7, 2026.

A client with Original Medicare and standard Medigap Plan G still pays the Part B deductible themselves. Plan G picks up the 20% Part B coinsurance that Medicare leaves after the deductible, but not the deductible itself, which is $283 for 2026. So the first covered therapy visits of the year can leave a balance until the client’s deductible is met.

How the two payers split a session

1. Medicare pays first. Until the client’s Part B deductible is met, covered charges go toward it. After that, Medicare pays 80% of the approved amount when you accept assignment.

2. The claim crosses over. For a Medicare supplement set up as secondary, Medicare normally forwards the claim automatically. When we add a client’s Plan G behind Medicare, nothing else is usually needed from the practice.

3. Plan G pays the coinsurance. The supplement then pays the remaining Part B coinsurance under its policy, but leaves the deductible portion to the client.

Medicare explains this order in how Medigap works, and its benefit comparison shows Plan G covering Part B coinsurance but not the Part B deductible. The current deductible is in CMS’s 2026 Part B fact sheet.

Before you tell a client they owe the deductible

• Confirm it is really Plan G. The insurer’s name does not tell you the plan letter, and neither does a 20% figure in an eligibility response. Read the letter from the card or policy. A high-deductible Plan G only pays after Medicare-covered cost sharing reaches its own threshold ($2,950 in 2026), and Massachusetts, Minnesota and Wisconsin standardize Medigap differently.

• Confirm it is Original Medicare. Medigap does not pay Medicare Advantage cost sharing. A client on an Advantage plan needs that plan’s benefits instead.

• Check how much deductible is actually left. Other providers’ claims count toward the same deductible, so the full annual amount may not still be outstanding.

• Check that the supplement is active. Supplements can lapse or be suspended without the client realizing it. When a client learned theirs had been suspended, we held automatic patient charges for that visit while they sorted it out.

Reading the balance that is left

Not every dollar left on a crossed-over claim belongs to the client or the supplement. In one reconciliation, the “remaining insurance balance” on a group of claims matched Medicare’s contractual adjustments, not anything the supplement owed, and Medicare’s coinsurance was a separate line. Read the Medicare remittance first: separate the deductible, the coinsurance and any contractual adjustment, then check what the supplement did with the coinsurance.

A supplement showing a claim as paid confirms status, not the amount or that the money reached you. Match the payment before posting it, and do not resubmit a claim that is still crossing over.

If the client also has Medicaid as a Qualified Medicare Beneficiary, QMB billing protections bar billing them for Medicare cost sharing, including the deductible. For enrollment and assignment questions, see Medicare participating vs non-participating vs not enrolled.

Frequently Asked Questions

Does Plan G pay the Part B deductible?

No. Standard Plan G leaves the Part B deductible to the client; Plan C and Plan F cover it, but they cannot be bought by people new to Medicare since 2020.

Do I need to bill the Medigap plan separately?

Usually not. Medicare typically crosses the claim over to the supplement automatically once the supplement is on file as secondary. Follow up only if the supplement has no record of it.

Why does a Plan G client owe nothing later in the year?

Once their Part B deductible is met, Medicare pays 80% and Plan G pays the 20% coinsurance for covered services.

Sources

• Medicare.gov: Compare Medigap Plan Benefits

• Medicare.gov: How Medigap Works

• CMS: 2026 Medicare Parts A & B Premiums and Deductibles

• CMS and NAIC: Choosing a Medigap Policy, 2026

• CMS: Qualified Medicare Beneficiary Program