Mich. Admin. Code R. 460.2572
Rule 72. The following statistical records shall be retained for the periods listed:
(a) Annual financial, operating, and statistical reports regularly prepared in the course of business for internal administrative or operating purposes (and not used as the basis for entries to the accounts of the companies concerned) to show the results of operations and the financial condition of the utility. | 5 years after date of report. |
(b) Quarterly, monthly, or other periodic financial, operating, and other statistical reports as described in subdivision (a)of this rule. | 2 years. |
(c) All other statistical reports not covered elsewhere in these rules that are prepared for internal administrative or operating purposes only and that are not used as the basis for entries to the accounts of the company. | Destroy at option. |
(d) Summaries of expenditures on maintenance and job orders and clearance to operating and other accounts, exclusive of plant accounts. | 6 years. |
Mich. Admin. Code R. 460.2572