29 CFR 409.5: Maintenance and retention of records.

Each surety required to file any report under this part shall maintain records on the matters required to be reported which will provide in sufficient detail the necessary basic information and data from which the reports filed with the Office of Labor-Management Standards may be verified, explained or clarified and checked for accuracy and completeness, and shall keep such records available for examination for a period of not less than 5 years after the filing of the reports based on the information which they contain.