29 C.F.R. § 4000.42
What definitions do I need to know for these rules?
eCFR amendment effective 2017-01-01 · current text
You need to know two definitions from
§ 4001.2 of this chapter: PBGC and person. You also need to know the following definitions:
Business day means a day other than a Saturday, Sunday, or Federal holiday.
We means the PBGC.
You means the person responsible, under our regulations, for the filing or issuance to which these rules apply.