Post-tax HSA contributions above the IRS limit

Question

Through a payroll error this year I over-contributed to my HSA.

I know that I am able to request a taxable disbursement for this amount before my filing date. However, I am having difficulty finding clear information on post-tax contributions.

Many sites suggest that post-tax contributions are allowed provided you claim them as "above the line" on your tax filing (and pay the taxes if they were incorrectly reduced from you gross income).

But the IRS guidelines I found don't say anything about post-tax contributions.

Some links suggest that you owe a 6% excise tax on top of your income tax for these post-tax contributions if they are not refunded before Apr 15th ... Does this, then, mean that I can pay a 6% one-time excise to get more money into this tax-advantaged account? If so then this sounds lucrative.

Answer 1

You cannot contribute to the HSA in excess to the limit. The "post-tax" contributions "some links" are talking about may be referring to the case where you cannot contribute through your paycheck. In that case - you contribute from your own (after-tax) money, and then claim deduction from your taxes above the line, i.e.: you end up getting the same tax benefit with the exception of the FICA taxes.

6% excise tax is yearly until you withdraw the excess and the earnings on it, and when you do withdraw the excess and the earnings - you'll pay your ordinary rate taxes on it. For each year, you have until April 15th the following year to withdraw the excess of that year without the penalty

From the IRS publication 969:

Generally, you must pay a 6% excise tax on excess contributions. See Form 5329, Additional Taxes on Qualified Plans (including IRAs) and Other Tax-Favored Accounts, to figure the excise tax. The excise tax applies to each tax year the excess contribution remains in the account.