Rule 23.Class Actions

Current through June 1, 2026 · Last verified July 10, 2026

In one sentenceRule 23 lets one or more people sue or be sued as representatives of an entire group when the group is too large to join individually, requires courts to certify and give notice to the class, and directs a share of any residual funds left over from the class recovery to a Colorado legal-aid foundation.

Full Text of Rule 23

Text sizeJump to: (a) (b) (c) (d) (e) (f) (g)

(a) Prerequisites to 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) Class Actions Maintainable. Any action may be maintained as a class action if the prerequisites of section (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 which would establish incompatible standards of conduct for the party opposing the class; or

(B) Adjudications with respect to individual members of the class which 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 interest; or

(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;

(D) The difficulties likely to be encountered in the management of class action.

(c) 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 shall determine by order whether it is to be so maintained. An order under this section (c) may be conditional, and may be altered or amended before the decision on the merits.

(2) In any class action maintained under subsection (b)(3), the court shall 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 shall advise each member that: (A) The court will exclude him from the class if he 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 he desires, enter an appearance through his counsel.

(3) The judgment in an action maintained as a class action under subsections (b)(1) or (b)(2), whether or not favorable to the class, shall 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 subsection (b)(3), whether or not favorable to the class, shall include and specify or describe those to whom the notice provided in subsection (c)(2) was directed, and who have not requested exclusion, and whom the court finds to be members of the class.

(4) When appropriate: (A) An action may be brought or maintained as a class action with respect to particular issues, or (B) a class may be divided into subclasses and each subclass treated as a class, and the provisions of this Rule shall then be construed and applied accordingly.

(d) Orders in Conduct of Actions. In the conduct of actions to which this Rule applies, the court may make appropriate orders:

(1) Determining the course of proceedings or prescribing measures to prevent undue repetition or complication in the presentation of evidence or argument;

(2) Requiring, for the protection of the members of the class or otherwise for the fair conduct of the action, the notice be given in such manner as the court may direct to some or all of the members of any step in the action, or of the proposed extent of the judgment, or of the opportunity of members to signify whether they consider the representation fair and adequate, to intervene and present claims or defenses, or otherwise to come into the action;

(3) Imposing conditions on the representative parties or on intervenors;

(4) Requiring that the pleadings be amended to eliminate therefrom allegations as to representation of absent persons, and that the action proceed accordingly;

(5) Dealing with similar procedural matters. The orders may be combined with an order under Rule 16, and may be altered or amended as may be desirable from time to time.

(e) Dismissal or Compromise. A class action shall not be dismissed or compromised without the approval of the court, and notice of the proposed dismissal or compromise shall be given to all members of the class in such manner as the court directs.

(f) Appeals. An appeal from a written, signed, and dated order granting or denying class certification under this rule may be allowed pursuant to the procedures set forth in C.R.S. § 13-20-901 (2003).

(g) Disposition of Residual Funds.

(1) “Residual Funds” are funds that remain after the payment of all approved class member claims, expenses, litigation costs, attorneys' fees, and other court-approved disbursements to implement the relief granted. Nothing in this rule is intended to limit the parties to a class action from suggesting, or the trial court from approving, a settlement that does not create residual funds.

(2) Any order, judgment, or approved settlement in a class action certified under this rule that establishes a process for identifying and compensating members of the class shall provide for the disbursement of residual funds, if any. In matters where the claims process has been exhausted and residual funds remain, not less than fifty percent (50%) of the residual funds shall be disbursed to the Colorado Lawyer Trust Account Foundation (COLTAF) to support activities and programs that promote access to the civil justice system for low income residents of Colorado. The court may disburse the balance of any residual funds beyond the minimum percentage to COLTAF or to any other entity for purposes that have a direct or indirect relationship to the objectives of the underlying litigation or otherwise promote the substantive or procedural interests of members of the certified class.

End

Amendment History

Amended September 18, 2003, effective nunc pro tunc July 1, 2003. Amended January 29, 2016, effective July 1, 2016. Amended effective June 29, 2022.

Plain-English Summary

Rule 23 lets a lawsuit proceed on behalf of a group of people who share the same basic dispute, rather than requiring every affected person to sue individually. A class action can go forward only if the class is too large for everyone to join as a party, the members share common legal or factual questions, the representative's claims are typical of the class, and the representative will protect the class's interests. Beyond that, the case must fit one of three categories: separate lawsuits would risk inconsistent rulings or would effectively decide absent members' rights, the opposing party has acted the same way toward the whole class so that injunctive or declaratory relief fits the whole group, or common questions predominate over individual ones and a class action is the better way to resolve the dispute.

Once a class action is filed, the court must decide early whether to let it proceed as a class action, and that decision can be revisited before the case is decided on the merits. Classes certified under the predominance category get the added protection of the best notice practical under the circumstances, including individual notice to identifiable members, so each person can opt out, stay in and be bound by the result, or enter an appearance through counsel. A class action cannot be dismissed or settled without court approval and notice to the class, and an order granting or denying certification can be appealed under the procedure set out in Colorado statute.

Colorado's rule adds a distinctly local requirement for money left over once a class recovery is paid out. After a certified class action is resolved — whether by court order, judgment, or approved settlement — and approved claims, fees, and costs are paid, the rule requires a plan for any residual funds instead of letting them go unclaimed. At least half of what remains must go to the Colorado Lawyer Trust Account Foundation to fund access to the civil justice system for low-income Coloradans, and a court can direct the rest to that foundation or to another organization connected to the purposes of the litigation.

Frequently Asked Questions

What four things does a class need to become certified?

Rule 23(a) requires that the class be too numerous to join individually, that common questions of law or fact exist, that the representative's claims are typical of the class, and that the representative will adequately protect the class's interests.

Can I opt out of a class action?

In a class action certified under the predominance category of Rule 23(b)(3), members receive notice and a chance to exclude themselves by a specified date; those who do not opt out are bound by the judgment.

What happens to money left over after a class action pays everyone?

Rule 23(g) requires that at least half of any residual funds go to the Colorado Lawyer Trust Account Foundation to support access to justice for low-income residents, with the court directing the remainder.

Can I appeal a judge's decision to certify or deny a class action?

Yes. Rule 23(f) allows an appeal from a written, signed, and dated order granting or denying class certification, following the procedure set out in Colorado statute.

Source & verification. The rule text is reproduced verbatim from the official Colorado Rules of Civil Procedure (Colo. R. Civ. P. 23). Prescribed by the Supreme Court of Colorado (C.R.S. § 13-2-108; Colo. Const. art. VI). The plain-English summary is original and written by us. Last verified July 10, 2026. · Official source

Also known as: class actionclass certificationopt out of class actionCRCP 23representative lawsuitresidual funds COLTAFclass action settlement