Mass. Gen. Laws ch. 164 § 94C
Whenever, in any proceeding before the department under section fourteen, ninety-two, ninety-two A, ninety-three, ninety-four, ninety-four A or ninety-four B, the reasonableness of any payment, charge, contract, purchase, sale, obligation or other arrangement between a gas or electric company and a company related to it as an affiliated company, as defined in section eighty-five, shall come into question, the burden of establishing and proving the reasonableness of such payment, charge, contract, purchase, sale, obligation or other arrangement shall be upon such gas or electric company.
For purposes of determining the value of an investment in an affiliated company, as defined by section eighty-five, in any proceeding before the department under the above named sections, the valuation shall be the lesser of the actual cost of the investment, as defined by the uniform system of accounts adopted by the department, or the net original cost of the property of the affiliate used and useful in providing service to the customers of the investing company.
Whenever the rates and charges of the affiliated company are regulated by the Federal Power Commission the department shall not establish rates and charges for the investing company which provide a higher return on the investment than that found to be fair and reasonable by the Federal Power Commission.
Mass. Gen. Laws ch. 164, § 94C