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Marissa S. Ronk


P. 303.244.0123 | F. 303.244.1879


Marissa Ronk represents sophisticated clients in complex commercial litigation and class and mass actions. She is a strategic leader, setting the direction and development of major cases to establish priorities, challenge and frustrate opponents, and create opportunities. Colorado Super Lawyers lists Marissa for Business Litigation, and Benchmark Litigation has named her to its 40 & Under Hot List.

A resourceful, proactive, and savvy leader, Marissa builds case strategies that align with clients’ business goals and values. Rather than react to opponents’ moves, she designs litigation plans that exploit pain points and increase leverage for her clients, whether as a plaintiff or defendant. For example, Marissa often develops counterclaims and pursues aggressive discovery to take an upper hand.

In addition to her practice, Marissa serves as a mentor in the Leadership Council on Legal Diversity and a co-chair of WTO’s associate review committee. Prior to joining WTO in 2015, she worked in the litigation department of Winston & Strawn in Chicago.


Commercial Litigation

Class & Mass Actions

  • After prevailing on a motion to dismiss all of plaintiffs' nationwide class claims, settled all claims individually for a major appliance manufacturer in a class action involving the doors in all of its microwave ovens.
  • Served as co-counsel in an oil and gas putative class action alleging violation of royalty rights. An early and aggressive discovery strategy persuaded the plaintiff to walk away from the matter.
  • Serving as lead national trial counsel to a major U.S. distributor of vaping products in federal multidistrict litigation in California. WTO is liaison counsel to all of the distributor defendants in the litigation.
  • Won a motion to dismiss with prejudice a putative class action in federal court in California. The plaintiff alleged violations of the Federal Fair Debt Collection Practices Act (FDCPA) and California's Rosenthal Fair Debt Collections Practices Act.
  • Represented a major Colorado manufacturer in its winning motion to dismiss class action litigation alleging illegal pesticide use.
  • Defended several manufacturers of high fructose corn syrup in a multimillion dollar dispute in which plaintiff alleged her consumption of the product caused her diabetes. The Western District of New York dismissed the complaint with prejudice and that dismissal was upheld by the Second Circuit.
  • Represented multiple corporations in various class action matters alleging recording of calls in violation of the California Invasion of Privacy Act. Negotiated dismissal of them all for a nuisance fee.
  • Defended a national automobile manufacturer in a putative class action alleging economic damage resulting from repairs to the driver's seat. Plaintiffs voluntarily dismissed their case without payment.

Publications & Speaking Engagements


Other Experience

Winston & Strawn LLP

Legal Memberships, Activities, and Honors

Colorado Super Lawyers
    Super Lawyers, Business Litigation, 2023-2024
    Rising Stars, Business Litigation - 2021
    Rising Stars, Personal Injury - Products Defense, 2018-2020   
The Best Lawyers in America
    Ones to Watch - Commercial Litigation, 2021, 2022, 2024
    Ones to Watch - Mass Tort Litigation / Class Actions - Defendants, 2021-2023
    Ones to Watch - Product Liability Litigation - Defendants, 2021, 2022, 2024
    Ones to Watch - Litigation - Labor and Employment, 2024
Benchmark Litigation
    Future Star, 2021-2023
    40 & Under Hot List, 2023-2024
Leadership Council on Legal Diversity
    Mentor, 2022 - present
    Fellow, 2022
Colorado General Counsel Mentoring Program, 2018-2020
International Association of Defense Counsel

Personal Interests

Cooking, biking, and Scrabble

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