25 CFR § 900.41 - How long must an Indian tribe or tribal organization keep management system records?
The Indian tribe or tribal organization must retain financial, procurement and property records for the minimum periods described below. Electronic, magnetic or photographic records may be substituted for hard copies.
(a) Financial records. Financial records include documentation of supporting costs incurred under the contract. These records must be retained for three years from the date of submission of the single audit report to the Secretary.
(b) Procurement records. Procurement records include solicitations, purchase orders, contracts, payment histories and records applicable of significant decisions. These records must be retained for three years after the Indian tribe or tribal organization or subcontractors make final payment and all other pending matters are closed.
(c) Property management records. Property management records of real and personal property transactions must be retained for three years from the date of disposition, replacement, or transfer.
(d) Litigation, audit exceptions and claims. Records pertaining to any litigation, audit exceptions or claims requiring management systems data must be retained until the action has been completed.