N.Y. Comp. Codes R. & Regs. tit. 16, § 196.8 – Classification of utilities.

(a) For the purpose of applying the system of accounts herein prescribed, municipal electric utilities are hereby grouped into the following four classes:
Class A. Utilities having average annual electric operating revenues of $500,000 or over
Class B. Utilities having average annual electric operating revenues of $100,000 or over, but under $500,000
Class C. Utilities having average annual electric operating revenues of $25,000 or over, but under $100,000
Class D. Utilities having average annual electric operating revenues of less than $25,000
(b) In order that frequent changes may be avoided, the class to which any utility belongs may be determined by the average of its annual electric operating revenues for the three fiscal years next preceding the effective date of this system of accounts. If, at the end of any fiscal year following, the average of its annual electric operating revenues for the three next preceding fiscal years is greater than the maximum for the class in which the utility has been grouped, it shall automatically be grouped in the higher class in which it falls because of such increased annual revenues. Any utility engaged in new undertakings, the annual revenue from which is not known in advance, shall be classed in accordance with a reasonable estimate of its prospective revenues.
(c) Any utility may, at its option, place itself in any group higher than the one in which it falls on the basis of its average annual electric operating revenues. Notice of such action shall be promptly filed with the commission.