A tax form distributed by the Internal Revenue Service (IRS) to claim a refund for certain taxes, interest and penalties. Individual taxpayers can use Form 843 to request, for example, a refund of Social Security or Medicare taxes withheld in excess or in error, or for penalties levied by the IRS in error.

Form 843 should not be used by individuals to claim an income tax refund, or to request a reduction of income, estate or gift tax. Businesses should not use the form to request an abatement of employment taxes, such as FICA.

Taxpayers have to file a separate Form 843 for each tax period and each tax type upon which an abatement or refund is being requested.

The IRS penalizes taxpayers who claim an excessive amount of refund. If the taxpayer is found to have abused the system, he or she will be fined 20% of the amount determined to be excessive. The penalty may be waived if the taxpayer had a reasonable basis to make the claim.