Key Takeaways

• PSHB coordination with Medicare Part B changes how coinsurance and out-of-pocket costs work for USPS retirees.
• Enrollment in Medicare Part B is now required for most Medicare-eligible USPS retirees under the new PSHB system.

Navigating health coverage as a USPS retiree is changing again in 2026. If you’re Medicare-eligible and part of the Postal Service Health Benefits (PSHB) Program, there are new rules about coinsurance, coverage, and enrollment you should know. This guide breaks down the essentials so you can stay confident about your benefits and avoid costly surprises.

What Is Medicare Part B Coinsurance?

Before understanding the changes, it’s important to know what coinsurance means, especially with Medicare Part B.

Coinsurance vs. Copay Differences

Coinsurance and copays are both forms of cost-sharing, but they work differently. A copay is typically a flat fee you pay for a healthcare service (like $20 for a doctor’s visit), regardless of the total bill. Coinsurance, on the other hand, is a percentage of the approved cost that you pay after any deductible is met.

For example, if your Medicare Part B coinsurance is 20%, and a service costs $200, you’d pay $40 while Medicare pays the remaining $160—assuming your deductible has already been met.

Typical Out-of-Pocket Costs

With traditional Medicare Part B, you generally pay:

• A monthly premium for Part B coverage
• An annual deductible (adjusted yearly)
• 20% coinsurance for most covered outpatient services, like doctor visits and lab tests

Coinsurance helps share the costs between you and Medicare. However, it’s important to recognize that some services may have separate rules or exceptions.

How Part B Coinsurance Works

After you meet your annual deductible, Medicare pays 80% of the approved amount for covered services. You pay the remaining 20% as coinsurance. This applies to:

• Office visits
• Outpatient surgeries
• Lab and diagnostic tests
• Durable medical equipment

Supplemental coverage, like PSHB or Medigap, often helps offset or cover your coinsurance liability. In 2026, PSHB integration makes these relationships more important than ever.

How Has PSHB Changed USPS Retiree Coverage?

Recent years have brought major health benefits changes for USPS retirees. Understanding the foundation can help you transition smoothly.

FEHB to PSHB Transition Overview

Previously, retirees chose coverage through the Federal Employees Health Benefits (FEHB) Program. With the creation of PSHB, starting January 1, 2025, USPS retirees and their eligible family members now have distinct plans within the PSHB Program. These plans are specifically designed for current and former USPS employees, separate from general federal retiree offerings.

PSHB Launch in 2025: Key Dates

Key PSHB milestones include:

• 2024: Open season education and PSHB plan preview
• January 1, 2025: PSHB coverage begins for all eligible USPS retirees, replacing FEHB
• 2026: Full coordination with Medicare Part B coinsurance requirements for Medicare-eligible retirees becomes the norm

Medicare Enrollment Requirements

For the first time, most Medicare-eligible USPS retirees and their covered family members are required to enroll in Medicare Part B to maintain full PSHB benefits. This new rule aims to better coordinate coverage and ensure you have protection against coinsurance-related costs, but it also means enrollment and timing are critical for continued coverage.

What’s New With Part B Coinsurance in 2026?

A new year means new details. Here’s what’s changing about Part B coinsurance and how it affects you as a USPS retiree under PSHB.

2026 Policy Updates for USPS Retirees

In 2026, the coordination of benefits between PSHB and Medicare Part B is fully implemented. The main policies include:

• Most PSHB plans require Medicare-eligible retirees to have Medicare Part B,
• Benefits are coordinated so that Medicare pays first, then PSHB as secondary
• PSHB plans are structured to reduce or eliminate many out-of-pocket costs that would otherwise fall under the 20% coinsurance of Part B

Coinsurance Impacts Under PSHB

When you’re enrolled in both Medicare Part B and a PSHB plan, many PSHB plans provide payment for the coinsurance portion or help limit what you pay. For example, after Medicare pays its share (usually 80%), your PSHB plan may pay some or all of what’s left, reducing your direct costs.

However, the exact handling of coinsurance depends on your specific plan, the type of service, and whether you’ve met any plan-specific deductibles or cost-sharing minimums.

Out-of-Pocket Considerations

It’s important to check plan details each year. PSHB plans typically outline:

• Whether coinsurance or copays apply
• Covered services and any exceptions
• Your annual out-of-pocket maximums

Knowing these details will help you anticipate your costs during the year and avoid surprises if you need care.

Who Needs to Enroll in Medicare Part B?

Enrollment is now a central requirement for many USPS retirees.

OPM Eligibility Rules Explained

The Office of Personnel Management (OPM) requires that most Medicare-eligible USPS retirees and their covered family members enroll in Medicare Part B to keep full PSHB benefits. You’re considered Medicare-eligible if you qualify for Medicare due to age (65+) or disability.

There are some limited exceptions, such as if you have other creditable coverage. It’s best to verify your specific situation with official resources before making decisions.

PSHB Participation and Part B

To get the maximum level of benefit coordination and limit your out-of-pocket costs, being enrolled in both Part B and your PSHB plan is now the standard expectation. Not enrolling in Part B could reduce your benefits or increase your share of the bills.

Enrollment Timelines for USPS Retirees

You should enroll in Medicare Part B within your Initial Enrollment Period (the 7-month window around your 65th birthday) or when you first become eligible due to disability. If transitioning from active work to retirement, check for Special Enrollment Period options. Missing these deadlines can mean late enrollment penalties and coverage gaps.

Is Coinsurance Always Required With PSHB?

Coinsurance is not always unavoidable—here’s when it matters for you.

When It Applies (And When It Doesn’t)

Coinsurance most often applies for Part B-covered services. But with PSHB plans, many covered retirees see these costs reduced or paid in full when both plans coordinate correctly. Some services may require you to pay a share, while others are fully covered after Medicare pays first.

Primary and Secondary Payer Coordination

Medicare is generally the primary payer for eligible retirees. PSHB becomes the secondary payer, covering costs that Medicare does not, up to plan limits. This structure is designed to prevent you from being responsible for the full coinsurance amount.

Tips for Understanding Your Costs

• Review your PSHB plan’s Summary of Benefits
• Contact your plan for current 2026 cost details
• Confirm with your health providers that they accept Medicare and your PSHB plan

By staying informed, you can minimize uncertainty about who pays what.

How Do PSHB and Medicare Work Together?

Smart coordination of benefits makes health coverage more secure.

Coordination of Benefits Overview

With both Medicare and PSHB, benefits are coordinated to avoid duplicate payments or missed coverage. Medicare pays approved expenses first; your PSHB plan typically picks up some or all of the remainder, reducing your exposure to coinsurance or out-of-pocket costs.

Examples of Claims Processing

Imagine you visit your doctor. Medicare is billed and pays 80% of an approved charge. Your PSHB plan is then billed for the balance. If your plan covers the coinsurance entirely, you may owe little or nothing; if it covers a portion, you pay the remaining amount up to your plan limits.

Avoiding Coverage Gaps

To ensure continuous coverage:

• Maintain up-to-date enrollment with both Medicare and PSHB
• Keep track of changes to both programs each year
• Save records of claims and paid bills

Reliable coordination between plans reduces the risk of unexpected bills and keeps your healthcare affordable and predictable.