Class Action Defense: Strategies From Certification to Arbitration

Class action defense strategies are the tools corporations and their attorneys use to defeat, narrow, or contain lawsuits brought on behalf of large groups, and the work spans every stage of a case: contract drafting years before filing, pre-suit motions, the fight over class certification, expert challenges, discovery, and settlement. The stakes explain the intensity. In 2025, corporations paid more than $70 billion to settle class actions, a record, and plaintiffs filed over 13,000 new federal class action suits. Courts granted more than 68% of class certification motions that year, up from 63% in 2024.¹ Against that backdrop, defense work is a layered exercise: block certification if possible, control the terrain if the class is certified, and manage the settlement if it comes.

Why Certification Is the Central Fight

The single most consequential moment in most class actions is the decision on certification. If a court grants it, the defendant faces claims on behalf of potentially thousands or millions of people, and settlement pressure increases sharply. If certification is denied, the case usually dies or shrinks to a single plaintiff’s claim. Defense lawyers concentrate their heaviest firepower here.

Under Federal Rule of Civil Procedure 23, a plaintiff seeking certification must satisfy four threshold requirements. The class must be so numerous that joining every member individually is impractical (numerosity). There must be legal or factual questions common to the class (commonality). The named plaintiff’s claims must be typical of the class (typicality). And the representative must adequately protect the interests of the class (adequacy). Most damages class actions must also show that common questions predominate over individual ones and that a class action is the superior method for resolving the dispute.²

Predominance is often the most decisive of these fights. Defendants argue that individual issues — how each person was harmed, what each person relied on, how damages should be calculated for each member — overwhelm whatever the class has in common. When a proposed class spans multiple states, defense counsel highlight variations in state law to argue that no single legal framework governs the claims.³

Commonality gets attacked under the Supreme Court’s standard in Wal-Mart Stores, Inc. v. Dukes, which held that a class must identify a “common contention” whose resolution will drive the outcome of every claim “in one stroke.” That case involved 1.5 million female Wal-Mart employees alleging gender discrimination, and the Court found that a corporate policy of giving local managers broad discretion was not itself a policy of discrimination — there was no “glue” holding the claims together.⁴ Defendants also challenge typicality by showing that a named plaintiff faces unique defenses or has circumstances materially different from the broader class, and they contest adequacy by questioning whether class counsel has the resources or whether the named plaintiff has sufficient knowledge and alignment with class members’ interests.³

Early Motions Before Certification

Experienced defense teams do not wait for a certification hearing. Several motions can narrow or eliminate class claims before expensive discovery begins.

A Rule 12(b)(6) motion to dismiss challenges the legal sufficiency of the complaint. Even when it does not end the case entirely, it educates the court on merits weaknesses and can expose problems, such as a lack of standing or variable legal standards, that later prevent certification.⁵

Defendants can also move to strike class allegations directly. Under Rule 12(f), an “immaterial” matter can be struck within 21 days of service; under Rule 23(d)(1)(D), courts can order pleadings amended to eliminate class allegations at any time if the allegations are facially deficient. The Fifth Circuit endorsed this approach in Elson v. Black (2023), affirming the striking of class allegations before discovery even opened.⁶

Pre-certification summary judgment is another route. If the defense defeats the named plaintiff’s individual claim before a class is certified, the case often ends, because finding and substituting a new representative is costly and time-consuming.⁵

These motions carry risk. A denial can reinforce a court’s impression that certification is appropriate. Even so, defense practitioners treat them as opportunities to preview their strongest arguments early and shape the trajectory of the case.⁵

Challenging the Plaintiff’s Experts

Plaintiffs in class actions rely heavily on experts: economists to model classwide damages, statisticians to prove common impact, social scientists to establish patterns of behavior. Defendants counter with Daubert motions asking the court to exclude expert testimony that fails the reliability standards of Federal Rule of Evidence 702.

If a plaintiff’s expert is excluded, the evidentiary foundation for certification can collapse. In Comcast Corp. v. Behrend (2013), the Supreme Court held that a class cannot be certified when the plaintiff’s damages model does not isolate damages caused by the specific theory of liability accepted for class treatment.⁷ Defense counsel routinely invoke Comcast to demand that damages methodologies match the surviving liability theory with precision.

Federal circuits treat Daubert differently at certification. The Third, Fifth, Sixth, Seventh, and Eleventh Circuits require a full reliability analysis when challenged expert testimony is material to the certification motion.⁸ The Eighth and Ninth Circuits use a more limited, “tailored” review focused on reliability rather than full trial-stage admissibility.⁹ The Sixth Circuit’s 2024 decision in In re Nissan North America reinforced the trend toward demanding full gatekeeping, reversing a certification order because the lower court failed to assess the reliability of an expert whose opinion was central to the plaintiffs’ commonality argument.

Defense teams increasingly present their own affirmative experts rather than only attacking the plaintiff’s. In Bowerman v. Field Asset Services (9th Cir. 2023), the Ninth Circuit reversed a certification order after the plaintiff’s expert was withdrawn, finding that individual issues predominated once the aggregate damages model fell apart.¹⁰

Standing and Uninjured Class Members

One of the most potent defense tools in recent years has been the argument that a proposed class includes people who were never actually harmed. The Supreme Court addressed this in TransUnion LLC v. Ramirez (2021), holding that “only plaintiffs concretely harmed by a defendant’s statutory violation have Article III standing to seek damages.” Of an 8,185-member class, the Court found that 6,332 members lacked standing because their inaccurate credit files were never sent to third parties. They had suffered a statutory violation but no real-world injury.¹¹

Defense counsel now use TransUnion to argue that proposed classes are “overinflated” with uninjured members, which both defeats standing and undermines the predominance analysis. The Supreme Court has not fully resolved the issue. In June 2025, it dismissed the writ in Labcorp v. Davis without deciding whether courts may certify a damages class that includes uninjured members.¹² Justice Kavanaugh dissented, arguing the answer is plainly no, but the question remains live.¹³ Federal circuits are splitting. The Fourth Circuit has held that a high share of uninjured members raises standing concerns, while the Fifth Circuit has adopted an approach requiring only named plaintiffs to have standing.

One consequence of TransUnion, as the dissent in that case warned, is that plaintiffs increasingly file class actions in state courts, where standing requirements can be more lenient than under Article III.¹⁴

Moving the Case to Federal Court

When a class action is filed in state court, the Class Action Fairness Act of 2005 (CAFA) gives defendants a route to federal court. Federal jurisdiction is available if the class has more than 100 members, at least one class member is of diverse citizenship from at least one defendant, and the total amount in controversy exceeds $5 million.¹⁵

CAFA loosens the traditional removal rules in ways that favor defendants. Any single defendant can remove without the consent of others. In-state defendants, who cannot remove under standard diversity jurisdiction, are eligible. There is no one-year time limit for filing the removal notice. And unlike ordinary removal, a court’s decision to remand a CAFA case back to state court is subject to appellate review.¹⁶¹⁵ Courts have also held that there is no presumption against CAFA removal, so defendants do not face the anti-removal tilt that applies in ordinary diversity cases.¹⁷

CAFA carves out exceptions for local controversies. Federal courts must decline jurisdiction, for example, when more than two-thirds of class members and the primary defendant are from the same state.¹⁵ Plaintiffs’ attorneys sometimes draft complaints to invoke these exceptions, and defendants counter by challenging the residency-based class definitions used to trigger them.¹⁷

Arbitration Clauses and Class Waivers

Perhaps no defense strategy has reshaped class litigation more than the widespread adoption of arbitration agreements containing class action waivers. The legal foundation rests on a line of Supreme Court cases. AT&T Mobility v. Concepcion (2011) established that the Federal Arbitration Act preempts state laws invalidating class waivers in arbitration agreements.¹⁸ Epic Systems Corp. v. Lewis (2018) extended this to employment, holding that employers can require workers to arbitrate disputes individually and waive class or collective action rights, and that such agreements do not violate the National Labor Relations Act.¹⁹

There is growing support for “stand-alone” class action waivers that operate independently of any arbitration requirement. The New Jersey Supreme Court upheld a stand-alone waiver in a residential lease in Pace v. Hamilton Cove (2024), and an Oregon federal court enforced one in Porteous v. Flowers Foods (2025), finding that arbitration and class waivers are “conceptually distinct.” California remains the most challenging jurisdiction for these clauses. Courts there may still scrutinize non-arbitration waivers for unconscionability.¹⁸

The Mass Arbitration Backlash

The success of class waivers produced an unintended consequence. Starting around 2018, plaintiffs’ firms began filing thousands of individual arbitration demands simultaneously against the same company, exploiting the fact that the company’s own arbitration agreement required it to pay substantial per-case filing fees. One company faced over 12,000 demands and more than $18 million in initial fees alone.²⁰

Arbitral bodies responded with procedural reforms. The American Arbitration Association’s Mass Arbitration Supplementary Rules, effective January 2024 and revised April 2024, apply when 25 or more similar demands are filed with coordinated representation. The rules call for appointment of a “process arbitrator” to resolve threshold issues before cases proceed, require mandatory global mediation within 120 days, and replace per-case upfront fees with a flat $11,250 initiation fee, of which the business pays $8,125. JAMS adopted similar procedures effective May 2024, triggered at a threshold of 75 or more coordinated claimants.²¹

Companies have also revised their contracts. Common additions include bellwether provisions selecting 20 to 50 test cases to be resolved first, batching clauses that hear claims in groups rather than all at once, and mandatory pre-arbitration informal resolution periods. These provisions face legal risk. California district courts have found bellwether and batching clauses unconscionable in several cases, citing the potential for claimants to wait years for a hearing.²²

Personal Jurisdiction as a Defense

The Supreme Court’s 2017 decision in Bristol-Myers Squibb Co. v. Superior Court created an ongoing question. Does the Constitution require courts to verify that they have personal jurisdiction over the claims of every unnamed class member, not just the named plaintiff? If so, nationwide class actions could be limited to forums where the defendant is subject to general jurisdiction.

The most comprehensive survey of federal district court rulings on this question found that roughly 78% of rulings reaching a firm conclusion held that exercising jurisdiction over unnamed class members remains permissible despite Bristol-Myers. Courts allowing jurisdiction typically distinguish class actions from the mass-tort context in Bristol-Myers by noting that unnamed class members are not treated as “parties” for purposes of venue or standing. The minority position, concentrated in certain districts and particularly the Northern District of Illinois, holds that jurisdiction must exist independently for each member’s claims.²³ No federal appellate court has issued a binding resolution, and the Supreme Court has not extended Bristol-Myers to class actions, leaving the issue as what legal scholars describe as “difficult and unsettled.”²⁴

Managing Discovery

Discovery in class actions is expensive and asymmetric. Defendants typically hold the bulk of relevant documents, and plaintiffs seek broad production. Since 2015, Federal Rule 26(b)(1) has required discovery to be “proportional to the needs of the case,” weighing factors like the amount in controversy, the parties’ relative access to information, and whether the burden outweighs the likely benefit.²⁵

In practice, studies have found the proportionality amendment has had “little impact” in the class action context, with courts remaining “especially liberal” in granting discovery relevant to class certification.²⁶ Defendants nonetheless use proportionality to object to overly broad electronic discovery requests, arguing that searches unrelated to the specific claims are disproportionate. A critical early decision is whether to invest in certification-specific discovery immediately or combine it with merits discovery to avoid duplication. Technology-assisted review, predictive coding, and e-discovery experts are now standard tools for managing large document productions.²⁷

Decertification After the Order

A certification order is not permanent. Under Rule 23(c)(1)(C), it can be “altered or amended before final judgment,” and the Supreme Court has described certification orders as “inherently tentative.” Courts grant decertification when new facts or changes in law show that certification is no longer appropriate. Examples include situations where post-certification discovery reveals that a damages expert cannot deliver the classwide model promised at certification, that a named plaintiff lied about material facts, or that a change in law shifts the analysis to require individualized inquiries.²⁸

Motions that simply rehash arguments from the original certification fight are typically rejected. Success is highest when defendants can point to a specific representation the plaintiff made during certification that has since been undermined.²⁸

Managing Settlement

When a class is certified and the case moves toward resolution, defense-side settlement requires managing a distinct set of risks. Defendants typically negotiate “blow” provisions, thresholds specifying that if too many class members opt out, the settlement falls apart.²⁹ Courts must approve any settlement as “fair, reasonable, and adequate” under Rule 23(e)(2), and defendants must build a record demonstrating the settlement’s value.

“Professional objectors,” attorneys who file generic protests to settlements with the aim of extracting payments to drop an appeal, are a persistent problem. Under Rule 23(e)(5)(B), no payment can be made for withdrawing an objection without court approval. Defendants and class counsel often cooperate to investigate objectors’ histories and request preliminary orders requiring disclosure of prior objection activity.²⁹ Settlement agreements may also include “quick-pay” provisions that pay class counsel’s fees upon district court approval regardless of any pending appeal, removing the financial incentive for counsel to pay off objectors.³⁰

Early settlement carries its own dangers. Paying large amounts can signal vulnerability and invite follow-on or “copycat” lawsuits. Some firms specialize in recruiting class members to opt out of settlements to pursue independent claims afterward. For that reason, some defense strategists advocate a trial-oriented posture from the start, preparing aggressively for trial rather than signaling willingness to settle.³¹

The Current Environment

With more than 68% of certification motions granted in 2025, record settlement dollars, and thousands of new filings, the defense side works in a demanding environment. Widening circuit splits on standing for uninjured class members, personal jurisdiction, and conditional certification standards for employment claims create a patchwork of rules that makes forum selection a front-line strategic decision for both sides.¹ The traditional arbitration defense continues to face erosion through mass arbitration tactics and judicial scrutiny of anti-mass-arbitration contract provisions.³² In securities class actions, 2025 saw 207 new federal filings, 155 dismissals, and a median settlement of $17 million, a ten-year high.³³ Effective defense work now assumes that no single tactic will carry the case: the strategies layer together, and the choice of which to press first often depends on the forum, the rule the plaintiff has invoked, and the shape of the proposed class itself.

1
Duane Morris LLP. Duane Morris Class Action Review 2026
2
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3
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4
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5
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6
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7
Justia. Comcast Corp. v. Behrend, 569 U.S. 27
8
Inside Class Actions. No Evading Daubert at Class Certification Stage, Sixth Circuit Rules
9
Skadden. Litigating Expert Testimony at the Class Certification Stage
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11
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American Antitrust Institute. Class Action Issues Update, Fall 2025
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Workplace Class Action Blog. False Start: U.S. Supreme Court Declines to Decide Whether Courts May Certify Damages Classes That Include Uninjured Class Members
14
Ellis Winters. TransUnion LLC v. Ramirez: A Pyrrhic Victory for Class Action Defendants
15
Bill Rubenstein, Harvard Law School. CAFA Analysis
16
Cornell Law Institute. 28 U.S. Code Section 1453
17
Greenberg Traurig. Class Action Fairness Act Advanced Removal Strategies
18
Dentons. Enforceability of Stand-Alone Class Action Waivers
19
Supreme Court of the United States. Epic Systems Corp. v. Lewis, 584 U.S. ___
20
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21
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22
Holland & Knight. Shielding Against the Mass Arbitration Surge
23
Yale Law Journal. Did Bristol-Myers Squibb Kill the Nationwide Class Action
24
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25
Quinn Emanuel. Recent Decisions Regarding Discovery Scope and Proportionality Requirements Under New Federal Rules
26
Vanderbilt Law Review. Proportionality in Class Action Discovery
27
Jones Day. Defending Class Actions
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29
Bloomberg Law. Objectors and Opt-Outs in Class Actions
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31
Crowell & Moring. Rethinking the Class Actions Strategy
32
Duane Morris Class Action Review. Duane Morris Class Action Review 2026
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NERA Economic Consulting. Recent Trends in Securities Class Action Litigation, 2025 Full-Year Review