Rev. Proc. 2021-19, page 1008.

This revenue procedure provides guidance with respect to the United States and area median gross income figures for use by issuers of qualified mortgage bonds under § 143(a) of the Internal Revenue Code and issuers of mortgage credit

certificates under § 25(c) (collectively, “issuers”) in computing the income requirements under § 143(f). This revenue procedure provides that issuers must use either (1) the income figures the Department of Housing and Urban Development (“HUD”) released most recently or (2) the income figures HUD released immediately prior to the income figures HUD released most recently, determined as of the date a mortgage loan or mortgage credit certificate is committed to a mortgagor. This revenue procedure also provides a 90day transition period, following the release of the HUD income figures in a current calendar year, for issuers to use the income figures HUD released during the second calendar year prior to the current calendar year..