Mayer Brown brought in two prominent partners from WilmerHale to rebuild its mass torts practice following significant departures in mid-2026. Davina Pujari and Chris Rheinheimer joined the firm as partners in its Litigation & Dispute Resolution practice, with Pujari appointed as leader of the Mass Torts, Product Liability & Environmental Law group. This move came after Mayer Brown lost an entire five-partner mass torts team to Jenner & Block’s Chicago office in June 2026—a departure that had weakened one of the firm’s core litigation practices.
The hiring represents a strategic recalibration in a competitive market where top mass tort talent commands significant leverage. Both partners bring decades of experience in complex environmental defense, product liability, class and mass actions, and False Claims Act litigation—skill sets that Mayer Brown identified as critical to restore after the Jenner & Block exodus. The two hires, combined with deputy practice leader Gina Aiello, now form the leadership core of the rebuilt practice.
Table of Contents
- Who Are Davina Pujari and Chris Rheinheimer?
- What the Departures to Jenner & Block Meant
- The Context of Mass Tort Competition in 2026
- Pujari and Rheinheimer’s Specific Skill Match
- The Risk of Unproven Integration
- What This Means for Environmental and Energy Litigation
- Implications for False Claims Act and Procurement Defense
Who Are Davina Pujari and Chris Rheinheimer?
Davina Pujari spent years at WilmerHale building expertise in environmental and white-collar defense, handling class and mass actions, False Claims Act litigation, and crisis management across regulatory enforcement matters. Her practice reflected the kind of cross-cutting litigation skills that apply across multiple practice areas—she wasn’t a narrow specialist but rather someone who could navigate complex regulatory investigations while managing large-scale client exposure. At Mayer Brown, she assumed the formal leadership title immediately, signaling the firm’s intent to center her judgment in rebuilding strategy and practice focus.
Chris Rheinheimer’s background centered on complex environmental, energy, and real-estate litigation, with particular depth in class and mass action defense and False Claims Act matters. Like Pujari, Rheinheimer brought experience in state and federal enforcement defense, suggesting familiarity with multi-jurisdictional coordination that mass tort defense often demands. Rheinheimer shares the deputy leader role with Gina Aiello, who remained at Mayer Brown through the Jenner & Block transition—her continuity in the second deputy role provided institutional memory during a period of significant upheaval.
What the Departures to Jenner & Block Meant
The loss of five partners to Jenner & Block in June 2026 created an unusual situation: a major Am Law 100 firm suddenly found itself rebuilding an entire practice leadership layer rather than making incremental hires. Five-partner team departures are relatively rare in the legal market; they typically occur when clients have relationship loyalty to specific attorneys and when the departing partners believe an alternative firm offers better economics, positioning, or support for their practice direction. Jenner & Block’s Chicago base made it a logical destination for lawyers interested in Midwest manufacturing and product liability exposure, where the firm has long-standing strength.
This wasn’t a situation where Mayer Brown had simply underinvested in mass torts or where market conditions had gradually eroded the practice. Instead, it was a sudden loss of institutional leadership that required aggressive hiring to restore credibility with existing clients and to remain competitive for new matters. The speed with which Mayer Brown brought in Pujari and Rheinheimer—within weeks of the Jenner & Block departure—indicated that the firm had not sat idle during the transition. This reactive hiring, while sometimes viewed as defensive, can also accelerate change if the incoming partners reshape practice priorities.
The Context of Mass Tort Competition in 2026
Mass tort and product liability practices have become increasingly concentrated at a subset of firms that can handle multi-state coordination, regulatory coordination, and insurance coverage disputes simultaneously. Firms like Skadden, Latham, Kirkland, Orrick, and Greenberg Traurig have built practices with dozens of partners who can deploy resources across simultaneous matters. Mid-tier powerhouses like Jenner & Block, Paul Weiss, and Jones Day have invested heavily in the space because product liability defense and mass tort work generates substantial hourly billing and long-term client relationships.
Mayer Brown, as an Am Law 50 firm with global reach, has the financial capacity to support a significant mass tort practice—but maintaining one requires retaining high-caliber partners and attracting lateral hires before competitors do. The Jenner & Block defection suggested that either the five partners believed Jenner & Block offered better opportunity or that Mayer Brown’s positioning in mass torts had become unclear. Bringing in Pujari and Rheinheimer signals Mayer Brown’s commitment to reclaim that position, but it also signals that the firm had to spend capital on recruitment that competitors might not have faced.
Pujari and Rheinheimer’s Specific Skill Match
Davina Pujari’s expertise in environmental defense is particularly relevant because environmental product liability claims—including contamination, hazardous materials exposure, and remediation disputes—often overlap with consumer product liability. False Claims Act experience is relevant because many government procurement disputes involve product defect allegations or quality compliance failures. Her white-collar defense background suggests she can also handle criminal-adjacent investigations arising from product-related incidents, a niche skill that few practitioners combine with civil mass tort defense.
Chris Rheinheimer’s energy and real-estate litigation experience addresses an underserved segment within product liability: cases involving industrial equipment, construction products, and energy infrastructure. His False Claims Act depth is relevant in government contractor contexts, where product defects can trigger False Claims Act liability in addition to personal injury claims. The combination of these two partners’ skill sets suggests Mayer Brown intends to compete across multiple product liability verticals rather than focusing narrowly on consumer products or pharmaceuticals.
The Risk of Unproven Integration
Bringing in lateral partners, even highly credentialed ones, carries a risk that their practice won’t flourish in the new environment. Different firms have different client cultures, staffing models, and billing expectations. Rheinheimer and Pujari built their practices at WilmerHale under that firm’s management structure and client relationships; translating those relationships and that operational style to Mayer Brown requires alignment that isn’t automatic.
Firms that excel at integrating laterals tend to have strong leadership from the existing practice and clear messaging about what clients can expect from the combined team. Another risk is that Mayer Brown’s clients may have been following the five partners who departed to Jenner & Block, leaving Pujari and Rheinheimer with a client base that needs rebuilding. In competitive lateral moves, the departing partners often carry client relationships with them; the arriving partners may find that the clients they inherited at their new firm are smaller or less active than they were at their old firm. This is not Pujari and Rheinheimer’s fault—it’s simply the economics of partner defections—but it requires aggressive new business development to restore practice volume.
What This Means for Environmental and Energy Litigation
Pujari’s and Rheinheimer’s backgrounds in environmental and energy litigation represent a meaningful expansion of Mayer Brown’s capacity in these areas. Environmental product liability encompasses contamination from products (e.g., asbestos, lead paint, water contamination chemicals), which blends product liability doctrine with environmental regulation. Energy litigation covers equipment defects, pipeline failures, and drilling-related incidents—industries where catastrophic events can trigger both mass tort and environmental remediation claims simultaneously.
Firms with depth in both product liability and environmental law can advise clients on the full scope of exposure when a product causes environmental harm. For example, a defective industrial solvent supplier faces not just product liability claims from direct users but also environmental contamination liability to property owners and regulatory enforcement from state environmental agencies. Pujari’s and Rheinheimer’s combined background suggests Mayer Brown can coordinate both the civil claims and the regulatory response—a value proposition that fewer firms can credibly offer.
Implications for False Claims Act and Procurement Defense
Davina Pujari’s specific expertise in False Claims Act litigation is noteworthy because the False Claims Act has become a vehicle for indirect product liability claims in government procurement contexts. When a contractor supplies a defective product to a government entity, the government can pursue a False Claims Act claim alleging that the contractor falsely certified the product met specifications—bundling product liability exposure with qui tam liability and treble damages. Chris Rheinheimer’s energy and real-estate background means his False Claims Act experience likely involved equipment and infrastructure contracts where product defects directly trigger compliance violations.
For Mayer Brown’s client base—particularly industrial manufacturers, energy companies, and construction product suppliers—this skill set addresses a specific pain point. A single product defect can simultaneously trigger personal injury mass torts (from users of the product), environmental remediation claims (if the product contaminated soil or water), False Claims Act liability (if the product was sold to government entities), and state regulatory enforcement. Few firms can seamlessly coordinate defense across all four liability vectors; Pujari and Rheinheimer’s combination of expertise suggests Mayer Brown is now positioned to do exactly that.
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