My guess would be an MLR rebate.  I did some research a few years ago and didn't come up with anything conclusive.  If that's what it is, google "MLR rebate".  It's very situational.  If there was no tax benefit from the overpaid premium in the prior year then a partial refund of a non-deductible expense is not taxable income.  If there was a medical deduction or SEHI in the prior year then it may be a taxable recovery under the tax benefit rule.  I had a whopping $88 one year that I just picked up as other income.

Rick