Mich. Admin. Code R. 500.91
Rule 21. The factors set forth in sections 403, 436a, 1341, 1342, and 1343 of the act, MCL 500.403, 500.436a, 500.1341, 500.1342, and 500.1343, are not an exhaustive list. In determining the adequacy and reasonableness of an insurer's surplus, no single factor is necessarily controlling. Instead, the director considers the net effect of all of these factors, plus other factors bearing on the financial condition of the insurer. In comparing the surplus maintained by other insurers, the director considers the extent to which each of these factors varies from company to company, and in determining the quality and liquidity of investments in subsidiaries, the director considers the individual subsidiary and may discount or disallow its valuation to the extent that the individual investments warrant.
Mich. Admin. Code R. 500.91