Employer health costs jump 8.2% in 2027

The steepest increase since 2003 is forcing workers to compare their company plan with Medicare. But that comparison has a hidden trap most people miss.

Medicare enrollment ends HSA contributions immediately

The moment you enroll in any part of Medicare, including free Part A, your HSA eligibility stops. Your annual contribution limit becomes prorated based on months you were eligible.

You can still contribute for earlier months

After Medicare starts, you can deposit money to cover those earlier eligible months, as long as total contributions stay within your prorated limit. Whatever is already in the account stays there tax-free for life.

Social Security creates a retroactive enrollment trap

When you file for Social Security after 65, the Social Security Administration automatically enrolls you in Part A and backdates it up to six months. Those retroactive months shrink your HSA contribution limit after the fact.

Excess contributions trigger a 6% annual tax

Contributions made during retroactive months that exceed your new prorated limit are subject to income tax plus a 6% excise tax for each year the excess sits uncorrected.

“Contributions made during that stretch do not automatically become excess. Only the amount above the newly prorated limit does, and that froth is subject to income tax plus a 6% excise tax for each year it sits uncorrected.”

Stop HSA contributions six months early

The clean fix is to stop all HSA contributions, including employer match, at least six months before you plan to claim Social Security or enroll in Medicare.

Medicare premiums rise with your income

Income-related surcharges on Part B can reach six hundred eighty-nine dollars ninety cents per month for high earners. These surcharges are based on your income from two years prior, not your current year.

Run the full Medicare cost comparison

Compare your new employee cost share plus lost HSA tax breaks against the full Medicare stack: Part B, Part D, Medigap or Medicare Advantage, and any income-related surcharges.

Confirm your employer plan qualifies first

Verify your coverage is based on current employment and your employer has at least 20 employees. Below that threshold, Medicare becomes primary and delaying Part B is unsafe.

Notify payroll in writing to stop contributions

If you decide to switch to Medicare, send written notice to payroll and confirm the employer contribution stops too. If Social Security is already filed, recalculate your prorated limit using the actual Part A effective date.