dissent and vote to modify in the following memorandum by Casey, J. Casey, J. (dissenting). Although the method for computing profit provided for in 11 NYCRR part 166 is not identical to that provided for in 11 NYCRR part 165, the Superintendent of Insurance could rationally construe the uniformity requirement of subdivision 5 of section 677 of the Insurance Law as prohibiting inconsistent results, rather than mandating identical formulas. Accordingly, we would modify the judgment to declare valid 11 NYCRR part 166.
First, it must be noted that while both parts 165 and 166 establish methods for computing profits, the purpose and scope *833of each part differ significantly. Part 165 was promulgated pursuant to article VII-A (§ 178, subd 3) of the Insurance Law as part of a comprehensive scheme to regulate insurance rates, prohibit anticompetitive behavior by insurers, promote competition and improve the availability and reliability of insurance (Insurance Law, § 175, subd 1), a scheme which is applicable to all but a few kinds of insurance (Insurance Law, § 175, subd 2). Accordingly, part 165 establishes a method for determining and reporting profitability for each kind of property and liability insurance (11 NYCRR 165.1 [a]). In contrast, part 166 was promulgated pursuant to article XVIII (§ 677, subd 5) of the Insurance Law, New York’s no-fault law, as part of a plan to ensure that any excess profits resulting from adoption of the no-fault law are returned to the consumers. Accordingly, part 166 establishes a method for determining excess profits on automobile insurance written in New York State during the 10-year period from January 1, 1974 through December 31, 1983 (11 NYCRR 166-1.0 [a]).
Subdivision 5 of section 677 of the Insurance Law provides that “[a]n excess profit shall be a profit beyond such percentage rate of return on net worth attributable to such policies, as computed in accordance with [part 165]”. Part 165 establishes a method for measuring profitability on a per company basis, using a complex system which includes certain industry-wide averages (11 NYCRR 165.3 [b]). The regulation further provides, however, that: “Whenever in the judgment of the superintendent, the calculation of profit for any company in accordance with the foregoing provisions does not produce reliable results * * * or whenever it can be shown that another method of calculation for such company will produce more reliable results, the superintendent may, in his discretion, permit or require the use of such other method of calculation or prescribe any other method of calculation which will produce more reliable results” (11 NYCRR 165.3 [c]). The majority discounts the importance of this authorization of an alternate method on the basis of a purported lack of evidence in the record to indicate that the superintendent exercised his discretionary authority under 11 NYCRR 165.3 (c), but in our view the promulgation of part 166 containing a different method for calculating profit constitutes the best evidence of the superintendent’s election to exercise his discretion.
Nor can it be said that a rational basis is lacking for the superintendent’s exercise of discretion. As noted above, the purposes and scopes of the legislation authorizing the promulgation of parts 165 and 166 differ significantly, thereby establishing the need for further inquiry into whether the use of identical *834formulas would be appropriate. The record establishes that a great deal of time and study went into the selection of a method which provides the most accurate means of determining excess profits resulting from the no-fault insurance law, and the result was the method contained in part 166. The regulation itself explains that aggregate industry data will be used, rather than individual insurer’s data (as in part 165), “to minimize random fluctuations, to avoid unfair treatment of insurers with differing financial makeup, and to permit the selection of one relatively low and logically defensible excess profit point” (11 NYCRR 166-1.2 [b]). This rationale is amplified in subpart 166-2 in a provision which begins by noting that “[t]here are serious technical problems in setting an excess profit threshold which is reasonable for each individual insurer” (11 NYCRR 166-2.2 [a]).
Thus, inasmuch as the statute requires only that profit in part 166 be determined “in accordance with” part 165 (Insurance Law, § 677, subd 5), and since part 165 gives the superintendent the discretionary authority to prescribe an alternate method (11 NYCRR 165.3 [c]), and there being a rational basis in the record and the regulations for the superintendent’s exercise of this authority with respect to determining excess profits under the no-fault insurance law, it cannot be said that part 166 violates the uniformity requirement of subdivision 5 of section 677 of the Insurance Law. Accordingly, the judgment should be modified to declare valid part 166.