15 U.S.C. § 15c

(a) Parens patriae; monetary relief; damages; prejudgment interest (1) Any attorney general of a State may bring a civil action in the name of such State, as parens patriae on behalf of natural persons residing in such State, in any district court of the United States having jurisdiction of the defendant, to secure monetary relief as provided in this section for injury sustained by such natural persons to their property by reason of any violation of sections 1 to 7 of this title. The court shall exclude from the amount of monetary relief awarded in such action any amount of monetary relief (A) which duplicates amounts which have been awarded for the same injury, or (B) which is properly allocable to (i) natural persons who have excluded their claims pursuant to subsection (b)(2) of this section, and (ii) any business entity. (2) The court shall award the State as monetary relief threefold the total damage sustained as described in paragraph (1) of this subsection, and the cost of suit, including a reasonable attorney’s fee. The court may award under this paragraph, pursuant to a motion by such State promptly made, simple interest on the total damage for the period beginning on the date of service of such State’s pleading setting forth a claim under the antitrust laws and ending on the date of judgment, or for any shorter period therein, if the court finds that the award of such interest for such period is just in the circumstances. In determining whether an award of interest under this paragraph for any period is just in the circumstances, the court shall consider only— (A) whether such State or the opposing party, or either party’s representative, made motions or asserted claims or defenses so lacking in merit as to show that such party or representative acted intentionally for delay or otherwise acted in bad faith; (B) whether, in the course of the action involved, such State or the opposing party, or either party’s representative, violated any applicable rule, statute, or court order providing for sanctions for dilatory behavior or other wise providing for expeditious proceedings; and (C) whether such State or the opposing party, or either party’s representative, engaged in conduct primarily for the purpose of delaying the litigation or increasing the cost thereof. (b) Notice; exclusion election; final judgment (1) In any action brought under subsection (a)(1) of this section, the State attorney general shall, at such times, in such manner, and with such content as the court may direct, cause notice thereof to be given by publication. If the court finds that notice given solely by publication would deny due process of law to any person or persons, the court may direct further notice to such person or persons according to the circumstances of the case. (2) Any person on whose behalf an action is brought under subsection (a)(1) may elect to exclude from adjudication the portion of the State claim for monetary relief attributable to him by filing notice of such election with the court within such time as specified in the notice given pursuant to paragraph (1) of this subsection. (3) The final judgment in an action under subsection (a)(1) shall be res judicata as to any claim under section 15 of this title by any person on behalf of whom such action was brought and who fails to give such notice within the period specified in the notice given pursuant to paragraph (1) of this subsection. (c) Dismissal or compromise of action An action under subsection (a)(1) shall not be dismissed or compromised without the approval of the court, and notice of any proposed dismissal or compromise shall be given in such manner as the court directs. (d) Attorneys’ fees In any action under subsection (a)— (1) the amount of the plaintiffs’ attorney’s fee, if any, shall be determined by the court; and (2) the court may, in its discretion, award a reasonable attorney’s fee to a prevailing defendant upon a finding that the State attorney general has acted in bad faith, vexatiously, wantonly, or for oppressive reasons.