Rider v. OXY USA: Ascertainability in the Tenth Circuit Requires Clear, Objective Class Definitions—not “Administrative Feasibility” or Classwide Standing Proof

1. Introduction

In Rider v. OXY USA, Inc. (10th Cir. May 5, 2026), royalty owners in the Kansas Hugoton Gas Field sought to certify a damages class under Federal Rule of Civil Procedure 23(b)(3) against OXY USA, Inc. (“Oxy”) and Merit Energy Company, LLC / Merit Hugoton, L.P. (collectively “Merit”). Plaintiffs alleged Defendants breached a 2008 Kansas state-court class settlement (the “Littell settlement”) that limited certain post-July 1, 2008 deductions from royalty payments.

After the district court denied certification—primarily because it found the class not “ascertainable” due to purportedly infeasible ownership/title tracing—the Tenth Circuit took an interlocutory appeal under Rule 23(f) and reversed, instructing the district court to certify a class consistent with the appellate opinion.

Key issues included: (i) what “ascertainability” requires in the Tenth Circuit after Cline v. Sunoco, Inc. (R&M); (ii) whether difficulties in matching payees to leases and successors in interest can defeat class certification; and (iii) how ascertainability errors can distort the remainder of the Rule 23 analysis.

2. Summary of the Opinion

The Tenth Circuit held that the district court applied an outdated, overly demanding view of ascertainability by effectively requiring proof of an “administratively feasible” identification method and by treating individualized ownership/title issues as a bar to certification. Relying on Cline v. Sunoco, Inc. (R&M), the court clarified that ascertainability in this circuit requires only a class definition that is (1) clear (not vague) and (2) objective (not subjective), and that class members can be identified with reasonable—but not perfect—accuracy.

The court further concluded that the district court’s ascertainability concerns “tainted” its analysis of commonality, typicality, adequacy, predominance, and superiority. Applying the correct standards, the Tenth Circuit held the class satisfied Rule 23(a) and 23(b)(3) and remanded with instructions to certify a class.

3. Analysis

3.1. Precedents Cited

  • Cline v. Sunoco, Inc. (R&M), 159 F.4th 1171 (10th Cir. 2025): The centerpiece of the opinion. Cline rejected the Third Circuit’s “administrative feasibility” requirement and adopted a definition-focused ascertainability standard: clear + objective, with identification possible at some stage using reasonable accuracy. Rider applies Cline to hold that record-review burdens, imperfect datasets, or the need to reconcile business records do not defeat ascertainability.
  • Rex v. Owens ex rel. Oklahoma, 585 F.2d 432 (10th Cir. 1978): Cited for the Tenth Circuit’s longstanding insistence that a class be ascertainable. The district court treated ascertainability as a sub-requirement of numerosity; the Tenth Circuit did not reject ascertainability as a requirement, but emphasized the correct (post-Cline) content of that requirement.
  • Sherman v. Trinity Teen Sols., Inc., 84 F.4th 1182 (10th Cir. 2023) and CGC Holding Co., LLC v. Broad & Cassel, 773 F.3d 1076 (10th Cir. 2014): Provided the standard of review and reinforced that courts must apply the correct legal standard and conduct a rigorous Rule 23 analysis.
  • Wal-Mart Stores, Inc. v. Dukes, 564 U.S. 338 (2011): Used for the core commonality framework—common contention capable of classwide resolution “in one stroke”—and for Rule 23(b)(3) framing.
  • Evans v. Brigham Young Univ., No. 22-4050, 2023 WL 3262012 (10th Cir. May 5, 2023): Cited as an example where ascertainability fails because membership turns on subjective inquiries (e.g., intent). The contrast supports Rider’s view that a payee-based class definition is objective.
  • Black v. Occidental Petroleum Corp., 69 F.4th 1161 (10th Cir. 2023): Addressed “uninjured class members” and cautioned that a class is too broad if a significant portion could not have been harmed. Rider distinguished Black as not requiring perfection at certification and emphasized that potential merits failures do not bar certification.
  • Messner v. Northshore Univ. HealthSystem, 669 F.3d 802 (7th Cir. 2012): Quoted via Black for the proposition that certification is not defeated because some class members’ claims may fail on the merits.
  • Mullins v. Direct Digital, LLC, 795 F.3d 654 (7th Cir. 2015); Rikos v. Procter & Gamble Co., 799 F.3d 497 (6th Cir. 2015); In re Nexium Antitrust Litig., 777 F.3d 9 (1st Cir. 2015): Cited to illustrate mainstream federal reluctance to impose heightened ascertainability hurdles and to acknowledge practical limits on excluding all uninjured members at certification, including “fail-safe class” concerns.
  • In re Motorola Secs. Litig., 644 F.3d 511 (7th Cir. 2011) and Powers v. Hamilton Cnty. Pub. Def. Comm'n., 501 F.3d 592 (6th Cir. 2007): Cited for the district court’s authority to modify a class definition (or for parties to do so by agreement).
  • Colo. Cross-Disability Coal. v. Abercrombie & Fitch Co., 765 F.3d 1205 (10th Cir. 2014): Used for the key procedural point that plaintiffs need not prove standing for every class member at the certification stage.
  • Menocal v. GEO Grp., Inc., 882 F.3d 905 (10th Cir. 2018): Cited for the proposition that individualized damages determinations do not defeat certification.
  • DG ex rel. Stricklin v. Devaughn, 594 F.3d 1188 (10th Cir. 2010): Typicality standard—claims need not be identical if based on the same legal/remedial theory.
  • Rutter & Wilbanks Corp. v. Shell Oil Co., 314 F.3d 1180 (10th Cir. 2002): Adequacy standard—conflicts and vigor of prosecution.
  • Garcia-Rubiera v. Calderon, 570 F.3d 443 (1st Cir. 2009): Used to justify appellate reversal with instructions to certify where Rule 23 prerequisites are plainly met.
  • Naylor Farms, Inc. v. Chaparral Energy, LLC, 923 F.3d 779 (10th Cir. 2019): Supports predominance in royalty underpayment cases where the defendant’s alleged systematic practice predominates, even if individualized issues remain for damages.
  • Stechschulte v. Jennings, 298 P.3d 1083 (Kan. 2013): Provided the elements of breach of contract (important because the claims are styled as breach of settlement/contract).
  • Olean Wholesale Grocery Coop., Inc. v. Bumble Bee Foods LLC, 31 F.4th 651 (9th Cir. 2022): Cited to reject the idea that certification is barred by the potential inclusion of more than a de minimis number of uninjured class members.

3.2. Legal Reasoning

A. Ascertainability after Cline: definition-focused, not logistics-focused

The district court denied certification because it believed identifying class members would require property-by-property title work and cross-referencing multiple record systems—an “administratively feasible” concern. The Tenth Circuit held that this approach conflicted with Cline v. Sunoco, Inc. (R&M), which expressly rejected “administrative feasibility” as part of ascertainability.

Applying Cline, the panel emphasized:

  • Clarity: A payee-based definition is sufficiently definite; Merit can identify who it paid from its records.
  • Objectivity: Membership turns on objective facts (paid royalties under specified leases/time period), not subjective intent (contrast Evans v. Brigham Young Univ.).
  • Reasonable accuracy: Class members need not be perfectly identified at certification; they must be identifiable with reasonable accuracy at some stage.
  • Defendant record issues: Under Cline, gaps/inaccuracies in a defendant’s records and the burden of reviewing many records cannot “hinder class certification.”

B. “Overbreadth,” successors, and standing concerns do not bar certification at this stage

Defendants argued the class was overbroad because many payees were not original Littell settlement participants and might not be “successors in interest,” so they would lack standing or have no claim. The Tenth Circuit rejected using these concerns to defeat certification:

  • No classwide standing proof required at certification: Under Colo. Cross-Disability Coal. v. Abercrombie & Fitch Co., plaintiffs need not prove standing for each absent class member at this stage.
  • Merits vs. certification: Echoing Black and Messner, the court stressed certification is not defeated because some class members’ claims might fail later.
  • Practical premise: Merit already pays royalties; if records are sufficient for routine payments, they are sufficient to identify recipients for any corrective relief should liability be established.

The court noted that certain boundary/new-well concerns might be alleviated by modest definition adjustments, and observed that district courts have authority to modify class definitions (citing In re Motorola Secs. Litig. and Powers v. Hamilton Cnty. Pub. Def. Comm'n.). But the panel still found the proposed class ascertainable and certification required.

C. Rule 23(a): commonality, typicality, adequacy

The panel held the district court’s Rule 23(a) analysis was infected by its mistaken premise that individualized ownership tracing defeated the existence of common questions and typical claims. Correctly framed, the litigation turns on classwide questions: whether the settlement binds Merit and/or Oxy and whether the deductions breached the settlement’s uniform limitation. Even “a single common question” can satisfy commonality under Wal-Mart Stores, Inc. v. Dukes, and here the court found multiple.

Typicality was satisfied because the named plaintiffs’ claims and the class claims arise from the same alleged settlement breach (citing DG ex rel. Stricklin v. Devaughn). Adequacy was satisfied because there was no showing of conflicts or lack of vigor, and one representative had prior experience as a class representative in the earlier Littell litigation (citing Rutter & Wilbanks Corp. v. Shell Oil Co.).

D. Rule 23(b)(3): predominance and superiority

Predominance was satisfied because the core liability questions—interpretation and breach of a uniform settlement royalty limitation and whether Merit and/or Oxy are bound—are susceptible to classwide proof (citing Cline v. Sunoco, Inc. (R&M) and the “class-wide scheme, policy, or practice” principle). Individualized damages and downstream entitlement issues do not generally defeat predominance (citing Menocal v. GEO Grp., Inc. and Cline), and royalty cases can be cohesive where the alleged underpayment practice is uniform (citing Naylor Farms, Inc. v. Chaparral Energy, LLC).

Superiority followed: a class action is an efficient vehicle to adjudicate an alleged breach of a class settlement, and administrative difficulties—while potentially relevant—cannot be used as a “trump card” to defeat certification (again relying on Cline’s framing).

3.3. Impact

  • Ascertainability doctrine in the Tenth Circuit: Rider operationalizes Cline by reversing a denial that effectively resurrected “administrative feasibility.” District courts must focus on whether the definition is clear and objective, not on the burdens of record review or defendant data imperfections.
  • Oil-and-gas royalty class actions: The decision reinforces that alleged systematic royalty underpayment practices—especially those tied to a uniform contract/settlement term—are prime candidates for Rule 23(b)(3) treatment, even when individual ownership and payment histories vary.
  • Successor/standing disputes: Defendants cannot front-load merits-heavy ownership tracing and standing objections to block certification. Such issues may be addressed later (e.g., claims administration, damages allocation, or merits adjudication) without destroying predominance.
  • Settlement enforcement via new class litigation: The court’s final observation—“the ideal method to litigate the breach of a class action settlement”—signals receptivity to class mechanisms to police uniform settlement-performance obligations when a successor operator takes over assets and changes deduction practices.

4. Complex Concepts Simplified

  • Ascertainability: Whether the class is defined in a way that lets the court determine who is (and is not) in it. After Cline, the Tenth Circuit asks whether the definition is clear and objective, and whether members can be identified with reasonable accuracy.
  • “Administrative feasibility” (rejected as an ascertainability requirement): A heightened demand that plaintiffs prove a convenient, efficient method for identifying members at certification. The Tenth Circuit rejects this as a standalone barrier to certification; logistical difficulty does not equal legal impossibility.
  • Predominance: Whether common issues (especially liability issues) matter more than individualized ones. Even if damages vary person-to-person, predominance can still be satisfied.
  • Fail-safe class (referenced in discussion of other circuits): A class defined so that membership depends on winning on the merits (e.g., “all persons whose rights were violated”). Courts are wary of such definitions; Rider favors objective, merits-independent criteria like payment records and lease assignments.
  • Rule 23(f): A discretionary interlocutory appeal mechanism that allows appellate review of class certification orders before final judgment.

5. Conclusion

Rider v. OXY USA, Inc. is a forceful application of the Tenth Circuit’s modern ascertainability doctrine: class certification cannot be denied merely because identifying every rightful claimant may require substantial record work, reconciliation of payee data, or later-stage ownership validation. By treating administrative difficulty and successor-title disputes as certification blockers, the district court misapplied Rule 23. The Tenth Circuit corrected course, holding the class definition was clear and objective and that the Rule 23(a) and (b)(3) requirements were satisfied—then remanded with instructions to certify a class consistent with its opinion.