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Sonya Winner

A litigator with three decades of experience, Sonya Winner handles high-stakes civil cases for clients in a wide range of industries, including banking, pharmaceuticals and professional sports.  She has handled numerous antitrust and consumer disputes, many of them class actions, in state and federal courts across the country.

Sonya’s cases typically involve difficult technical issues and/or complex legal and regulatory schemes. She is regularly able to resolve cases before the trial phase, often through dispositive motions. But when neither summary judgment nor a favorable settlement is an option, she has the confidence of her clients to take the case all the way through trial and on appeal. Her recent successes have included a cutting-edge decision rejecting a “true lender” challenge to National Bank Act preemption in a class action involving interest rates on student loans, as well as the outright dismissal of a putative antitrust claim against the National Football League and its member clubs asserting an unlawful conspiracy to fix cheerleader compensation.

Sonya has been recognized as a leading trial lawyer by publications like Chambers and the Daily Journal. She is chair of the firm’s Class Action Litigation Practice Group.

Expert evidence commonly plays an important role in class certification determinations.  On August 5, the Seventh Circuit addressed this issue, holding that in a proposed antitrust class action, the district court erred in certifying a class when it failed to engage with conflicting expert evidence regarding antitrust impact that could have established lack of predominance.        

The case, Arandell Corp. v. Xcel Energy Inc., — F.4th —, 2025 WL 2218111 (7th Cir. 2025) was a long-running natural gas price fixing case.  Plaintiffs moved to certify a Rule 23(b)(3) class.  They argued that common questions of law or fact predominated, including “whether the class paid higher prices for natural gas[.]”  Id. at *4.  Plaintiffs and defendants had competing experts on the predominance issue as it related to impact.  Id. Continue Reading District Courts Must Address Conflicting Expert Evidence to Certify Antitrust Class Action, Seventh Circuit Rules

A court in the Northern District of California recently denied Google’s request to prevent more than 69,000 putative class members from opting out of a certified class in favor of pursuing individual arbitration of their claims against Google.  See In re Google Assistant Privacy Litig., 2025 WL 510435, at *1

Continue Reading California Federal Court Permits Thousands of Arbitration Opt-Outs from Certified Class