D.C. Circuit Strikes Down NLRB’s “Successor Bar” Doctrine: Post-Acquisition Ability to Challenge Union Representation Comes Sooner

Key Takeaways

• The U.S. Court of Appeals for the D.C. Circuit invalidated the NLRB’s “successor bar” doctrine, allowing challenges to union representation much sooner after many business acquisitions involving unionized employees.
• Employers acquiring unionized businesses may now have earlier opportunities to test whether a union still has majority employee support, although successor bargaining obligations remain unchanged.
• Companies pursuing acquisitions should revisit labor due diligence, post-closing bargaining strategy, and NLRA compliance because the decision could materially affect transaction planning and labor relations risk.

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When a company buys a business with unionized employees, it often inherits the obligation to work with the existing union. For over a decade, a National Labor Relations Board (“NLRB”) rule called the “successor bar” doctrine prevented anyone, including the acquiring employer or employees, from questioning whether a majority of employees still supported that union for up to a year after the acquisition closed. In its recent decision in Hospital Menonita de Guayama, Inc. v. NLRB, the United States Court of Appeals for the D.C. Circuit threw out the successor bar doctrine. The court specifically held that the NLRB exceeded its statutory authority by imposing a categorical insulated period following an acquisition during which employees’ majority support for the union could not be challenged, and that the successor bar doctrine violated workers’ rights under the National Labor Relations Act (“NLRA”) because it restricted employees’ ability to choose, or not choose, their union representation. This is one of the most significant labor decisions in the successorship area in recent years, and it is a major shift for employers acquiring unionized operations as it creates new options for both employers and employees who want to revisit the question of union representation after a deal closes.

Background: The Successorship Framework and the Successor Bar Doctrine

To understand why this ruling matters, it is important to understand how the law works when one company acquires another with a unionized workforce. Under longstanding Supreme Court precedent, if an employer purchases another company and then hires most of that company’s  unionized employees and continues operating the business in essentially the same way, the buyer becomes a “successor employer” to the seller. As a successor employer, the buyer must recognize and bargain with the union that represented those employees when they were employed by the seller. However, the buyer is not usually locked into the seller’s existing union contract. Instead, it is required to sit down with the union and negotiate new terms and conditions of employment from scratch.

The successor bar doctrine provides an additional layer of protection to unions following an acquisition. The modern form of the doctrine that is specifically at issue in Menonita was created by the NLRB in a 2011 case called UGL-UNICCO Service Co. Under the successor bar doctrine, a successor employer that was obligated to bargain with an existing union was prohibited from challenging the incumbent union’s majority status for a “reasonable period.” A reasonable period was generally six months up to one year, depending on factors such as whether the successor employer adopted or changed its predecessor’s existing terms and conditions of employment. During that window, no one (including employees or a rival union) could question whether the union had the support of a majority of the new workforce. Specifically:

• Employees could not petition to remove the union (a “decertification” petition);
• A rival union could not petition to replace the incumbent union;
• The employer could not ask the NLRB to hold an election testing whether employees still wanted the union;
• The employer could not poll employees to find out if they still supported the union; and
• The employer could not otherwise challenge the status of the union or withdraw recognition even if it had clear evidence that most employees did not want the union.

The incumbent union was effectively insulated from challenge for six months to a year, even if a majority of employees did not want representation.

Why the D.C. Circuit Invalidated the Successor Bar Doctrine

In the Menonita case, the D.C. Circuit struck down the successor bar doctrine because it conflicted with the basic principles of the NLRA – i.e., that employees have the right to choose whether or not they want union representation. Indeed, Section 7 of the NLRA does not just protect the right to unionize; it equally protects the right to not unionize. Further, Section 9 of the NLRA mandates that a union must represent the majority of employees to serve as their exclusive representative. The court found that the successor bar doctrine runs afoul of Section 7 and Section 9 because it makes it impossible for employees to decide whether they want union representation for the duration of the successor bar period and may allow a union to act as an exclusive representative when it lacks majority support. The court also pointed to key differences between the successor bar doctrine and other situations where challenges to union status are temporarily blocked or limited, such as after an election or during the term of an existing CBA. In short, the court concluded that the NLRB did not have statutory authority to prevent employees from exercising their right to accept or reject union representation simply because a business changed ownership.

A key factor in the court’s willingness to closely scrutinize the Board’s authority to create the successor bar was the Supreme Court’s 2024 decision in Loper Bright Enterprises v. Raimondo, which eliminated the deference courts previously extended to agency interpretations of ambiguous statutes under Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc. This reflects a broader shift in judicial interpretation of administrative law. Without Chevron deference, the D.C. Circuit was required to conduct its own independent review of whether the NLRA authorized the Board’s successor bar rule, rather than deferring to the Board’s own interpretation of its authority, and that independent review led the court to reverse its earlier decision and strike the rule down.

What Still Applies: The Continuing Bargaining Obligation

Importantly, this ruling does not mean employers can ignore unions after acquiring a business. The familiar successor framework that requires a successor employer to recognize and bargain with an incumbent union where there is substantial continuity in the business and a majority of the new workforce comes from the predecessor remains unchanged by this ruling. Therefore, the core rules about successor employers have not changed:

• If you buy a business and hire most of the seller’s unionized workers while running the same or a similar operation, you still must recognize and bargain with the union;
• The test for whether you are a “successor employer” has not changed; and
• You are likely not bound by the predecessor company’s union contract, but you do need to negotiate in good faith with the union over the terms of employment going forward.

The D.C. Circuit’s ruling only got rid of the waiting period. Before this new ruling, successor employers had to wait months or even a year before anyone could even ask the question: “Does this union still have majority support?” Now, that question can be asked much sooner after an acquisition.

How the Decision Affects Employers Acquiring Unionized Businesses

For employers involved in or planning acquisitions of unionized businesses, this ruling changes the playbook in several important ways:

1. Employees Can Seek to Remove the Union Sooner. Workers who do not support the incumbent union can now file a petition asking the NLRB to hold an election on whether to keep or remove the union. They no longer have to wait for a mandatory six-to-twelve-month period to expire. This matters most where there has been significant turnover in the workforce or where employees never had the chance to vote for the union themselves.
2. Employers Can Test Union Support Earlier. If a successor employer has a genuine, good-faith reason to doubt that the union has majority support, it can now ask the NLRB to conduct an election or can poll employees to find out where they stand almost immediately. This option was completely off the table for up to year under the successor bar doctrine.
3. Withdrawal of Recognition May Be Possible. If an employer has objective proof that most employees no longer want the union (for example, a signed petition from a majority of the workforce), the employer may be able to stop recognizing the union altogether and use the lack of majority support as a defense to an unfair labor practice charge. Previously, this evidence was irrelevant during the bar period. That evidence must still be obtained through lawful means, however, and unilateral withdrawal still carries significant unfair labor practice risk if the Board later disagrees that the union had, in fact, lost majority support.
4. Due Diligence Should Now Include Employee Sentiment. When evaluating a potential acquisition, buyers should try to understand how much support the union actually has with the workforce. Knowing whether employees genuinely support the union, or would prefer to move on, can shape a buyer’s entire post-closing labor strategy. Any such assessment should be carefully structured and vetted for NLRA compliance to avoid unlawful interrogation, promises of benefits, or other conduct that could violate employees’ Section 7 rights.
5. Unions Will Face More Pressure to Prove Their Value. Without the guaranteed protection period, unions can no longer assume they will have months of unchallenged status to establish themselves with a new employer. Successor employers should expect unions to move more aggressively in early bargaining and should plan their strategy accordingly.

Employers and employees alike should keep in mind that these expanded options must still be exercised in compliance with longstanding NLRA rules prohibiting coercive polling, unlawful employer assistance to decertification efforts, and other conduct that interferes with employees’ Section 7 rights.

Important Caveats and Continuing Risks

Overall, this is a favorable development for employers with unionized workforces, or those considering acquiring a company with a unionized workforce, but certain caveats and risks remain:

• This is one court’s decision. The D.C. Circuit’s ruling directly controls NLRB cases arising in that circuit, but other federal courts of appeals have not yet addressed the issue. Practically, this may affect how the NLRB approaches this issue nationwide, but this decision is not binding on other circuits. If your business operates in a different part of the country, the NLRB may continue to apply the successor bar until other courts weigh in or the Supreme Court takes up the issue, so employers operating in multiple regions should treat this decision as a sign that the doctrine is vulnerable and plan for the possibility of inconsistent application across circuits in the meantime.
• The NLRB may push back. The Board could ask for the case to be reheard, make another appeal to the Supreme Court, or try to craft a new version of the rule that would be viable. Changes in the composition of the NLRB could also affect how this plays out going forward.
• You still must bargain. To be clear, refusing to recognize or bargain with the union when you are legally required to do so, including as a successor employer, is still an unfair labor practice that can result in significant legal liability. This decision removes the insulation period preventing challenges to majority status, not the bargaining obligation.
• Politics matter in labor law. NLRB priorities often shift with presidential administrations. The NLRB’s priorities today may evolve depending on who is in charge. NLRB doctrine governing bars to challenging union status — including the successor, recognition, and contract bars — has historically shifted with changes in NLRB membership, so employers should expect the NLRB to explore alternative ways to preserve some measure of post-acquisition stability, especially after changes in administrations.

What Companies Should Do Before and After Acquiring a Unionized Business

If you are currently buying, or thinking about buying, a unionized business, here is what you should do:

• Revisit your game plan for any pending deals. If you are in the middle of acquiring a unionized operation, think about whether this ruling changes your approach to bargaining with the union or your timeline for addressing representation questions.

• Find out how employees feel. As part of your pre-closing due diligence, look for lawful ways to understand whether the majority of the workforce supports the union. This information is now more actionable than ever.

• Build a labor strategy with counsel. Work with your labor attorneys to develop an approach that takes advantage of this new legal environment while staying fully compliant with your obligation to bargain.

• Stay on top of developments. This area of law is moving fast. Other courts may weigh in, and the NLRB’s response will matter. Keep in close contact with counsel and monitor any related court decisions.

• Document, document, document. If you plan to challenge the union’s majority status, make sure any evidence of employee dissatisfaction is gathered and preserved carefully and lawfully.

• Coordinate any challenge with counsel. Any early challenge to the union’s majority status should be coordinated closely with counsel and supported by carefully gathered evidence, since the NLRB or a reviewing court may assess that evidence differently. For instance, if an employer withdraws recognition based on a petition that is later found to be tainted by unlawful employer involvement, the employer may face reinstatement of the union along with backpay and other remedial orders.

The D.C. Circuit’s decision in Hospital Menonita is a significant development for employers looking to acquire unionized businesses. While the duty to bargain with the union has not gone away, the days of being stuck without lawful options to test majority support for the union acquisition may be over.

For more information and guidance on managing risk related to unionized workforces, please contact any member of the AGG Employment team.