Rule 23. Class Actions
(a) Prerequisites to a Class Action. One or more members of a class may sue or be sued as representative parties on behalf of all only if:
(1) the class is so numerous that joinder of all members is impracticable;
(2) there are questions of law or fact common to the class;
(3) the claims or defenses of the representative parties are typical of the claims or defenses of the class; and
(4) the representative parties will fairly and adequately protect the interests of the class.
(b) Aggregation. The representative parties may aggregate the value of the individual claims of all potential class members to establish district court jurisdiction over a class action.
(c) Class Actions Maintainable. An action may be maintained as a class action if the prerequisites of Rule 23(a) are satisfied, and in addition:
(1) the prosecution of separate actions by or against individual members of the class would create a risk of:
(A) inconsistent or varying adjudications with respect to individual members of the class that would establish incompatible standards of conduct for the party opposing the class; or
(B) adjudications with respect to individual members of the class that would as a practical matter be dispositive of the interests of the other members not parties to the adjudications or substantially impair or impede their ability to protect their interests;
(2) the party opposing the class has acted or refused to act on grounds generally applicable to the class, thereby making appropriate final injunctive relief or corresponding declaratory relief with respect to the class as a whole; or
(3) the court finds that the questions of law or fact common to the members of the class predominate over any questions affecting only individual members, and that a class action is superior to other available methods for the fair and efficient adjudication of the controversy. The matters pertinent to the findings include:
(A) the interest of members of the class in individually controlling the prosecution or defense of separate actions;
(B) the extent and nature of any litigation concerning the controversy already commenced by or against members of the class;
(C) the desirability or undesirability of concentrating the litigation of the claims in the particular forum; and
(D) the difficulties likely to be encountered in the management of a class action.
(d) Determination by Order Whether Class Action to Be Maintained; Notice; Judgment; Actions Conducted Partially as Class Actions.
(1) As soon as practicable after the commencement of an action brought as a class action, the court must determine by order whether it is to be so maintained. The order may be conditional, and may be altered or amended before the decision on the merits.
(2) When determining whether an action may be maintained as a class action, the representative party’s rejection of an offer made under Rule 68 or other offer of compromise that offers to resolve less than all of the class claims asserted by or against the representative party has no impact on the representative party’s ability to satisfy the requirements of Rule 23(a)(4). When the representative party is unable or unwilling to continue as the class representative, the court must permit class members an opportunity to substitute a class representative meeting the requirements of Rule 23(a)(4), except in cases where the representative party has been sued.
(3) In any class action maintained under Rule 23(c)(3), the court should direct to the members of the class the best notice practicable under the circumstances, including individual notice to all members who can be identified through reasonable effort. The notice must advise each member that:
(A) the court will exclude the member from the class if the member so requests by a specified date;
(B) the judgment, whether favorable or not, will include all members who do not request exclusion; and
(C) any member who does not request exclusion may, if the member desires, enter an appearance through the member’s counsel.
(4) The judgment in an action maintained as a class action under Rule 23(c)(1) or (2), whether or not favorable to the class, must include and describe those whom the court finds to be members of the class. The judgment in an action maintained as a class action under Rule 23(c)(3), whether or not favorable to the class, must include and specify or describe those to whom the notice provided in Rule 23(d)(3) was directed, and who have not requested exclusion, and whom the court finds to be members of the class.
(5) When appropriate, an action may be brought or maintained as a class action with respect to particular issues, or a class may be divided into subclasses and each subclass treated as a class. In either case, the provisions of this rule should then be construed and applied accordingly.
(e) Orders in Conduct of Actions.
(1) When conducting actions to which this rule applies, the court may make appropriate orders:
(A) determining the course of proceedings or prescribing measures to prevent undue repetition or complication in the presentation of evidence or argument;
(B) requiring, for the protection of the members of the class or otherwise for the fair conduct of the action, that notice be given to some or all of the members in such manner as the court may direct:
(i) of any step in the action;
(ii) of the proposed extent of the judgment;
(iii) of the opportunity of members to signify whether they consider the representation fair and adequate;
(iv) to intervene and present claims or defenses; or
(v) to otherwise to come into the action;
(C) imposing conditions on the representative parties or on interveners;
(D) requiring that the pleadings be amended to eliminate therefrom allegations as to representation of absent persons and that the action proceed accordingly;
(E) dealing with similar procedural matters.
(2) The orders may be combined with an order under Rule 16, and may be altered or amended.
(f) Dismissal or Compromise. A class action must not be dismissed or compromised without the approval of the court, and notice of the proposed dismissal or compromise must be given to all members of the class in such manner as the court directs.
Advisory Committee Note—2019 Amendment
The amendments retain Rule 23 and add Rule 23(b) and (d)(2). Rule 23(b) permits aggregation of the value of class members’ claims to reach the district court threshold jurisdictional amount, and Rule 23(d)(2) permits substituting a class representative when a representative party is unable or unwilling to continue as the class representative.