Specific Instructions for Lines 6a, 6b, and 6c should be updated to add the following. The 4% minimum applicable credit percentage under section 42(b)(3) does not apply to three situations set forth in Revenue Ruling 2021-20 PDF and further discussed in Revenue Procedure 2021-43 PDF. Situation 1. The 4 percent floor under section 42(b)(3) does not apply to a building which is financed in part with a draw-down exempt facility bond issue that was issued in 2020 and on which one or more draws are taken after December 31, 2020. Situation 2. The 4 percent floor under section 42(b)(3) does not apply to a building which is financed in part with proceeds of an exempt facility bond issue that was issued in 2020 and in part with proceeds of a different exempt facility bond issue that is issued in a de minimis amount after December 31, 2020. Situation 3. The 4 percent floor under section 42(b)(3) does not apply to a building which receives an allocation of housing credit dollar amount in 2020 and a de minimis additional allocation after December 31, 2020. The analysis in this revenue ruling applies only for purposes of determining whether the 4 percent floor under section 42(b)(3) applies to a building.