Derek W. Loeser


1201 Third Avenue, Suite 3400
Seattle, WA 98101 

Derek is a senior partner in Keller Rohrback’s nationally recognized Complex Litigation Group and a member of the firm’s Executive Committee.

Derek's passion for holding large corporations accountable for wrongdoing has helped recover billions of dollars for consumers, retirees, governments and institutions. He has served in leadership roles in major complex cases across the country.

Currently, Derek is co-lead counsel in In re Facebook, Inc. Consumer Privacy User Profile Litigation, the MDL litigation against Facebook stemming from the Facebook Cambridge Analytica scandal. In the case, after years of hard-fought litigation, he and the team achieved a historic $725 million settlement, the largest amount paid to date to resolve a privacy-based class action. 

In addition to his class action work, Derek helps manage the Keller Rohrback team representing state and local government entities in a number of matters involving significant public health crises. For example, Derek leads the Keller Rohrback team litigating government cases against opioid manufacturers and distributors in The National Prescription Opioid Litigation. In the Opioid MDL, Derek serves on the Expert and Law & Briefing Committees and lead the litigation against a major opioid manufacturer. He also represents school districts and counties in litigation against the e-cigarette company, JUUL, for targeting and addicting youth, and in litigation against social media companies for causing a youth mental health epidemic. These cases are quintessential examples of the type of litigation Derek and the Keller Rohrback team fervently pursue: corporate fraud and malfeasance causing serious harm to the public.

Derek’s other notable cases include the Wells Fargo unauthorized account consumer class action for which Derek served as lead counsel. In the Wells Fargo case, Derek and the Keller Rohrback team achieved a $142 million settlement requiring the bank to refund all improper fees and provide first-of-its kind credit damage reimbursement, among other relief, to Wells Fargo customers; multi-billion dollar mortgage-backed securities cases on behalf of the Federal Home Loan Banks of Chicago, Indianapolis and Boston; ERISA class cases on behalf of employees whose retirement savings were decimated by corporate fraud and abuse on the part of Enron, WorldCom, Countrywide, and Washington Mutual, among others. He has also litigated fraud, RICO, and antitrust cases against drug manufacturers, pharmacy benefit managers, and insurance companies for conspiring to drive up the cost of life-saving medications such as insulin.
Many of Derek’s cases have required coordinating with state and federal agencies involved in litigation that parallels cases pursued by Keller Rohrback, including state attorneys general, the Department of Justice, and the Department of Labor. In addition, Derek has extensive experience negotiating complex, multi-party settlements, and coordinating with the many parties and counsel necessary to accomplish this. He is frequently asked to speak at national conferences about class actions, public health litigation, ERISA, and other complex litigation topics.

In 2024, Derek was recognized by Law360 as a "Titan of the Plaintiffs Bar."

Before joining Keller Rohrback, Derek served as a law clerk for the Honorable Michael R. Hogan, U.S. District Court for the District of Oregon. He was also a trial attorney in the Employment Litigation Section of the Civil Rights Division of the U.S. Department of Justice in Washington, D.C. where he prosecuted discrimination cases on behalf of the United States.


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