This document consolidates the regulations in TD 9904 and TD 9953, setting forth the final amended regulations to the Employment Tax Regulations under sections 3111 and 3221 of the Internal Revenue Code (Code) issued under the authority granted by the Families First Coronavirus Response Act and the Coronavirus Aid, Relief, and Economic Security Act, as well as under sections 3131, 3132, and 3134 of the Code, added by sections 9641 and 9651 of the American Rescue Plan Act of 2021.  These final regulations authorize the assessment of any erroneous refund of the tax credits paid under sections 7001 and 7003 of the Families First Coronavirus Response Act (including any increases in such credits under section 7005 thereof), and section 2301 of the Coronavirus Aid, Relief, and Economic Security Act, as well as under sections 3131, 3132 (including any increases in those credits under section 3133), and 3134 of the Code as if such amounts were tax liabilities under sections 3111(a), 3111(b) and 3221(a) subject to assessment and administrative collection procedures.