Rev. Proc. 99-21, Disability Suspension

The information is needed to establish a claim that a taxpayer was financially disabled for purposes of section 6511(h) of the Internal Revenue Code (which was added by section 3203 of the Internal Revenue Service Restructuring and Reform Act of 1998). Under section 6511(h), the statute of limitations on claims for credit or refund is suspended for any period of an individual taxpayer's life during which the taxpayer is unable to manage his or her financial affairs because of a medically determinable mental or physical impairment, if the impairment can be expected to result in death, or has lasted (or can be expected to last) for a continuous period of not less than 12 months. Section 6511(h)(2)(A) requires that proof of the taxpayer's financial disability be furnished to the Internal Revenue Service.

The latest form for Rev. Proc. 99-21, Disability Suspension expires 2021-04-30 and can be found here.