Michigan Compiled Laws, Chapter 500. Insurance Code of 1956 § 500.2027

(i) Race, color, creed, marital status, sex, national origin, gender, gender identity or expression, or sexual orientation, except that marital status may be used to classify individuals or risks for the purpose of insuring family units.

(ii) The residence, age, disability, or lawful occupation of the individual or the location of the risk, unless there is a reasonable relationship between the residence, age, disability, or lawful occupation of the individual or the location of the risk and the extent of the risk or the coverage issued or to be issued, but subject to subparagraph (iii). This section does not prohibit an insurer from specializing in or limiting its transactions of insurance to certain occupational groups, types, or risks as approved by the director. The director shall approve the specialization for an insurer licensed to do business in this state and whose articles of incorporation contained a provision on July 1, 1976, requiring that specialization.

(iii) For property insurance, the location of the risk, unless there is a statistically significant relationship between the location of the risk and a risk of loss due to fire within the area in which the insured property is located. As used in this subparagraph, “area” means a single zip code number under the zoning improvement plan of the United States Postal Service.