Claims can only be reimbursed from the same year's allowance, so if you get to the end of the plan year, and you have used up your entire annual allowance and still have a large bill that has not been fully reimbursed, those claims will automatically 0 out at the end of the year. They will not be able to be reimbursed from the next year's allowance.

For example, Sarah receives an HRA allowance of $400 per month. As of December 2022, she has received a total of $4,800 in allowance but only claimed $3,300 in reimbursement. Sarah has a remaining unclaimed balance of $1,500 for 2022 as of December.  

In December 2022 she receives a bill for surgery she had during October 2022 for $3,000, which she submits for reimbursement through her company’s HRA. The $1,500 of accrued unclaimed allowance from 2022 will be applied to that claim in December.

The remainder of the claims that are not reimbursed will 0 out.