For Mayer Brown, there’s no set formula for success when defending class actions and mass torts. Firm lawyers in Chicago last year delivered a string of victories by attacking each suit differently, finding and exploiting vulnerabilities in jurisdiction, standing, experts or facts.

“We don’t just go through a standard checklist of claims and defenses,” said Michael Olsen, who co-leads the firm’s mass tort and products liability practice. “We search for a hook.”