The employer tax is measured by the amount of wages paid after 1954 with respect to employment after 1936. See § 31.3121(a)-1 , relating to wages, and §§ 31.3121(b)-1 to 31.3121(b)-4 , inclusive, relating to employment. For provisions relating to time of payment of wages, see § 31.3121(a)-2 .
26 C.F.R. §31.3111-1