Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 164, § 31

A manufacturing or other corporation having its place of business in a city or town where a gas company proposes to manufacture gas for light may hold not more than ten per cent of the capital stock of such gas company; provided, that the foregoing provisions shall not prevent a domestic corporation having its principal place of business in the commonwealth from holding more than ten per cent of the capital stock of a gas company.