The modern Fair Labor Standards Act (FLSA) collective action sits on an awkward foundation. Individual wage claims are typically too small to litigate alone, so Congress allowed for an opt-in collective in order to aggregate them, while sidestepping the more demanding requirements of a Rule 23 class action. But the mechanism contains a structural flaw: The FLSA provides no clear way to notify potential members, and the limitations period — two years, or three for willful violations — never stops running until each individual files a consent to join.¹ The longer it takes to conduct discovery, litigate the scope of the collective, and notify the potential collective members, the more of each employee’s unpaid wage claims are consumed by the clock.

Into that tension, in 2023 the Sixth Circuit issued Clark v. A&L Homecare & Training Ctr., LLC,² rejecting the longstanding, easy-to-satisfy “conditional certification” rule for providing notice and imposing a requirement that the plaintiff show a “strong likelihood” that other employees are similarly situated before notice can be given.³

Clark addressed real problems with the prior standard: overly broad notice functioning as claim solicitation, settlement pressure untethered from merits, and front-loaded costs for defendants with individualized defenses. But it created a new problem: As the pre-notice phase lengthens, more of the short statute of limitations period runs before potential opt-ins learn the case exists. District courts are now improvising solutions, with inconsistent results.

THE LIMITATIONS-PERIOD PROBLEM

Under the FLSA, filing a complaint freezes the named plaintiff’s clock — but no one else’s. Instead, a non-named plaintiff’s statute of limitations stops running only when that employee files written consent to join the action.⁴ That differs from a Rule 23 class action, which tolls the limitations period during pre-certification proceedings.⁵ Thus, even diligent plaintiffs’ lawyers cannot file consents for employees unaware of the case. For decades, courts handled FLSA notice through a two-stage path: an early “notice stage” asking only whether plaintiffs made a “modest factual showing” of similarity, followed by a more rigorous post-discovery analysis.⁶ The Sixth Circuit’s pre-Clark approach accepted this framework, requiring only that plaintiffs show their position was “similar, not identical” to other, unnamed employees.⁷ While that approach had practical value — at the early stages of litigation, plaintiffs rarely have detailed evidence necessary to prove potential opt-ins are similarly situated — it also carried costs. “Conditional” certification often appeared as court-endorsed solicitation of the plaintiff’s claims, and the mere fact of conditional certification brought with it intense settlement pressure regardless of the merits of the claim.⁸

THE CLARK STANDARD AND THE DELAY PROBLEM IT CREATES

Clark ended this prior framework. It stressed that the old “certification” terminology, borrowed from the class action context, was misleading. Unlike class certification, FLSA “conditional certification” had no impact on the character of the underlying lawsuit, because FLSA claims become collective only when similarly situated employees affirmatively join.⁹ Clark thus held that notice should issue only if plaintiffs show a “strong likelihood” — a standard above a genuine issue of material fact but less than a preponderance — that the employees to be notified are similarly situated.¹⁰ The Court grounded that rule in the Supreme Court’s longstanding instruction that court-facilitated notice must not resemble “the solicitation of claims.”¹¹

This “strong likelihood” standard requires fact discovery — including what employees did what, under what policies, and subject to what defenses. That carries with it the delay inherent in discovery. And while the Clark majority tried to mitigate that delay by instructing district courts to “waste no time” adjudicating notice motions, “expedite” is not a magic word. The pre-notice discovery phase creates a built-in delay that can often consume much, if not all, of the two-year limitations period.

EQUITABLE TOLLING AS A SAFETY VALVE

Equitable tolling has become a frequently litigated topic in FLSA cases. Although the U.S. Supreme Court has clarified that the FLSA is subject to ordinary legal principles and burdens of proof rather than specialized rules,¹² rendering equitable tolling “a rare remedy to be applied in unusual circumstances, not a cure-all for an entirely common state of affairs,”¹³ courts nevertheless tend to apply equitable tolling in FLSA matters almost as a matter of course.¹⁴

Clark’s majority opinion neither adopted nor mentioned an equitable-tolling rule. But the panel’s two concurrences did. Judge Bush suggested that Clark’s heightened notice threshold “creates the need to toll the statute of limitations,” and that “something akin to” the automatic tolling in class-action cases “may be well suited” to FLSA collective actions.¹⁵ Judge White agreed with and expanded on Judge Bush’s tolling remarks, stating that under this new standard, district courts must “move quickly” and “should freely grant equitable tolling to would-be opt-in plaintiffs.”¹⁶

Litigators have seized on these opinions, with tolling becoming a standard feature in FLSA motions practice. And the instinct to seek tolling makes sense. But Clark did not answer the hard questions: Who can ask for tolling? When can a court grant it? When should tolling commence? And what showing is required? The absence of these answers is why district courts post-Clark have issued significantly inconsistent opinions.

THE LEGAL FAULT LINES CLARK LEFT EXPOSED

The tolling disputes following Clark implicate two significant unresolved questions.

Standing and advisory opinion concerns. The central justiciability argument is straightforward: A court may adjudicate only the rights of parties before it, and FLSA opt-ins are not parties until they file written consents. The Supreme Court has explained that Rule 23 certification creates a class with independent legal status, but FLSA “conditional certification” does not.¹⁷ Clark likewise emphasized that an FLSA collective action “is not representative,” because plaintiffs must “affirmatively choose” to join as parties.¹⁸ And the Supreme Court has consistently rebuffed requests for relief “extend[ing] beyond named parties.”¹⁹ A Court ruling on issues not germane to the parties before it, and instead related only to potential opt-ins, violates Article III’s prohibition against “advisory opinions” by allowing the Court to “pass ... judgments on theoretical disputes that may or may not materialize.”²⁰ There is thus a substantial question whether any court may adjudicate equitable tolling for yet-to-join opt-ins.

Several post-Clark district courts have denied pre-opt-in tolling on the above lack-of-standing grounds, concluding that a named plaintiff cannot invoke equitable tolling “on behalf of potential opt-in plaintiffs” because doing so would adjudicate the rights of people not before the court.²¹ Other district courts have permitted tolling, either by ignoring the standing issues²² or rejecting them without meaningful analysis.²³

Whether equitable tolling is statutorily permitted in FLSA cases. A separate issue is whether the FLSA permits tolling at all. Recent Supreme Court decisions have limited application of equitable tolling doctrine based upon statutory interpretation. In the Supreme Court’s 2023 decision in Arellano v. McDonough, the Court explained that equitable tolling cannot apply when it “is inconsistent with the statutory scheme,” because both statutory text and context can negate the general presumption that statutes of limitation are subject to equitable tolling.²⁴ Thus, when a statutory scheme “reinforces Congress’s choice to set effective dates solely as prescribed in the text,” courts treat those express exceptions as “detailed instructions” for how to “set effective dates solely as prescribed in the text.”²⁵ And this can occur when Congress “sets forth time limitations in unusually emphatic form” and “reiterates its limitations several times in several different ways.”²⁶ Indeed, in a recent unanimous opinion arising out of Michigan, the Supreme Court confirmed that when a statutory “provision speaks in strict, mandatory terms,” coupled with a statutory structure that “includes a default deadline and several exceptions,” equitable tolling is not proper.²⁷

The FLSA fits that description. Congress provided that “every” FLSA action “shall be forever barred unless commenced within two years” (or three for willful violations).²⁸ It also emphatically specified that the statute of limitations continues to run for opt-in plaintiffs until they file a written consent, and provides no exceptions.²⁹ And while Congress provided specific exceptions to these categorical limitations when it amended the FLSA back in 1947, none of those exceptions apply.³⁰ Indeed, it made specific congressional findings that the amendments were intended to curtail “immense,” judicially-created “liabilities” that had created an “extended and continuous uncertainty” for both employers and employees.³¹ Taken together, the history and structure of the FLSA support the argument that the statute reflects a deliberate design: a short limitations period, strict opt-in rules, and carefully crafted exceptions. None of this reflects congressional intent for the judicial branch to create new tolling rules for unidentified nonparties.

Courts in the Sixth Circuit have not yet applied Arellano’s statutory- limitation reasoning to a post-Clark tolling determination, but it remains an open question regarding — and potentially significant defense to — aggressive tolling requests.

PRACTICAL TAKEAWAYS

So where does that leave us? Post-Clark practice is converging on three observable patterns.

First, as emphasized in Clark, many courts authorize targeted pre-notice discovery aimed at the “strong likelihood” question and order a short discovery window.³² Second, courts are splitting over whether equitable tolling is properly raised before opt-ins formally exist. Many courts likely will deny tolling for lack of standing or find that it is an issue to be raised by specific opt-ins once they are parties.³³ Other courts have granted tolling more readily, often based on Clark’s dicta.³⁴

Third — and most practically — stipulated agreements on tolling (when acceptable for the parties) are becoming a best-available “fix.” A time-limited, precisely defined agreement can reduce motion practice and sidestep the justiciability problem created by asking a court to decide nonparties’ rights.³⁵

Taken all together, then, FLSA practitioners must adapt to the new state of play following Clark.

For plaintiffs’ counsel, that means that diligence is nonnegotiable after Clark. Courts that grant tolling often emphasize diligence; courts that deny tolling frequently describe generalized, prospective tolling as too speculative before opt-ins exist. The plaintiff who waits for months to move for notice — or who moves without a discovery plan tailored to the “likelihood” analysis — is wagering part of the collective’s recovery on a bet that procedural delay will be minimal.

And for defense counsel, Clark is not a free pass. The “strong likelihood” standard reduces some of the “certify now, litigate later” pressure, but it increases the risk that courts will use tolling, expedited discovery, or both to prevent the two-year limitations period from becoming a merits-independent defense. Courts will likely view a defense strategy aimed at contesting similarity and running out the clock as inconsistent with Clark’s “waste no time” instruction and with equitable principles.