Why Working Past 65 Is Especially Common in California
California has one of the highest rates of older workers in the country. With strong tech, healthcare, university, and government employment, many Californians stay employed well past 65. The Medicare rules for these workers are some of the most confusing in the entire program — and missteps can mean permanent penalties or coverage gaps.
This guide series covers the six most important decisions California workers face as they approach and pass 65 while still on employer health coverage.
The Foundational Rule
Whether you can delay Medicare without penalty depends primarily on the size of your employer:
| Employer Size | Medicare Status | Action Needed |
|---|---|---|
| 20+ employees | Employer plan is primary | You can safely delay Part B without penalty |
| Fewer than 20 employees | Medicare becomes primary at 65 | You must enroll in Part A and Part B at 65 |
The 6-Topic Working Past 65 Cluster
HSAs and Medicare — The 6-Month Lookback Rule
If you contribute to an HSA, enrolling in any part of Medicare (even just Part A) ends your eligibility to contribute. Worse: Part A is retroactive up to 6 months. Stop HSA contributions 6 months before Medicare enrollment.
Employer Plan Coordination — The 20-Employee Rule
The 20-employee threshold determines whether your employer plan or Medicare pays first. Plus: why COBRA does NOT count as creditable coverage for Medicare delay purposes.
Part B Special Enrollment Period — The 8-Month Window
Once you leave employer coverage, you have 8 months to enroll in Part B without penalty. Form CMS-L564 (Request for Employment Information) is your proof of creditable coverage.
Part D Creditable Drug Coverage — The 2-Month Window
For prescription drug coverage, your window after losing employer drug coverage is much shorter — only 63 days. Miss it and you pay a 1%/month permanent penalty.
Spouse on Employer Plan — How Coverage Works
If you’re 65 but covered under your working spouse’s employer plan, the same rules apply based on the spouse’s employer size. Special considerations for divorce and widowhood.
Retiring at 66, 67, 68, or 70 — Timing Strategies
Each retirement age presents different Medicare/Social Security coordination decisions. Why retiring mid-year creates the smoothest transition.
California-Specific Considerations
UC Retirement, CalPERS, and many California public agencies have specific rules about how their retiree health coverage coordinates with Medicare. Most require Part B enrollment to keep retiree benefits — even if you delayed Part B during active employment. Contact your benefits office well before retirement.