N.H. Rev. Stat. § 357-C:13
Actions arising out of any provision of this chapter shall be commenced within 4 years of the date the cause of action accrues; provided, however, that if a person conceals the cause of action from the knowledge of the person entitled to bring it, the period prior to the discovery of his cause of action by the person so entitled shall be excluded in determining the time limited for commencement of the action. If a cause of action accrues during the pendency of any civil, criminal, or administrative proceeding against a person brought by the United States, or any of its agencies, under the antitrust laws, the Federal Trade Commission Act, any other federal act, or the laws of the state related to antitrust laws or to franchising, such actions may be commenced within one year after the final disposition of such civil, criminal, or administrative proceeding.
RSA 357-C:13
1981, 477:2, eff. Aug. 25, 1981.