25 C.F.R. § 103.35
(b) The lender also must send written notice of the default to BIA by certified mail (return receipt requested), or by a nationally-recognized overnight delivery service (signature of recipient required) within 60 calendar days of the default, unless the default is fully cured before that deadline. This notice is required even if the lender grants the borrower a forbearance under § 103.36(a). One purpose of the notice is to give BIA the opportunity to intervene and seek assistance for the borrower, even though BIA has no duty, either to the lender or the borrower, to do so. Another purpose of the notice is to permit BIA to plan for a possible loss claim from the lender, under § 103.36(d). The lender's notice must clearly indicate: