Notice 2020-82 provides that the IRS will treat a contribution to a single-employer defined benefit pension plan with an extended due date of January 1, 2021 pursuant to § 3608(a)(1) of the CARES Act, as timely if it is made no later than January 4, 2021 (which is the first business day after January 1, 2021).
Notice 2020-82 will appear in IRB 2020-49, dated Nov. 30, 2020.