If you made a contribution to your Health Savings Account (HSA)
during 2017, but for the 2016 tax year, then that contribution would have been
reported on your 2016 tax return.
It should not be included on the 2017 tax return even though
the actual contribution was made during 2017.
However, if you did not remain an eligible individual
through 2017, then that contribution for 2016 will be considered an excess
contribution. Even though you were able
to contribute the maximum amount bsed on the last-month rule, you must remain
eligible for the following 12 months for the contribution to stand and not be
considered to be excess.
Take a look at the information below
from TurboTax help content if you want to know more:
Last Month Rule
Under the last-month rule, if you are an eligible individual on
the first day of the last month of the tax year (December 1), you are
considered an eligible individual for the entire year. You are treated as
having the same HDHP coverage for the entire year as you had on the first day
of the last month.
If you make contributions to your HSA based on you being an
eligible individual for the entire year under the last-month rule, you must
remain an eligible individual for the entire testing period under the
last-month rule. The testing period begins on the first of the last month of
your tax year and ends on the last day of the 12th month following that month.
Most of the time this is December 1 to December 31 of the next year.