Kellogg Hansen

Based in Washington, DC, Kellogg Hansen thrives on litigating complex cases at trial, including arguments before the U.S. Supreme Court and appellate courts. 

A Trial and Appellate Litigation Firm is Born

A relatively young firm, Kellogg Hansen was formed in 1993 when three BigLaw partners jumped ship to form their own small firm focused on trial and appellate litigation. Since then, the firm has grown to include more than 90 100 attorneys, all of whom are trial and appellate specialists. Nearly every partner and associate served as a law clerk for a federal judge, and more than a dozen clerked for U.S. Supreme Court justices. 

Litigation Powerhouse

In addition to strong practices in commercial, U.S. Supreme Court, and appellate litigation, Kellogg Hansen pursues matters involving government investigations, white collar defense, intellectual property and antitrust litigation, and telecommunications. The firm serves large and small clients in practically every kind of trial case (criminal and civil, contract and tort, antitrust and unfair competition, patent law, and government and corporate investigation). Because it does not have a corporate practice, the firm avoids conflicts of interest and can work on a variety of cases against all kinds of adversaries—including banks, accounting firms, insurance companies, and other law firms.

Although they work for clients in a wide range of industries, Kellogg Hansen attorneys have unique experience in the telecommunications industry and have represented companies such as Verizon and AT&T both in court litigation and before the Federal Communications Commission and state regulators. With several former federal prosecutors among its ranks, a significant portion of the firm’s practice involves representing or prosecuting corporate and individual clients in governmental investigations and parallel private civil litigation under state and federal fraud, securities, banking, antitrust, consumer protection, telecommunication, and healthcare statutes, as well as the Foreign Corrupt Practices and False Claims Acts.

Supreme

In addition to extensive experience in federal and state appellate courts, Kellogg Hansen’s attorneys are not afraid to take their cases to the very top. Kellogg Hansen attorneys have argued more than 70 cases before the U.S. Supreme Court, and a former firm partner—Neil Gorsuch—is now a Supreme Court Justice.

• Served as counsel for Meta in antitrust litigation culminating in a bench trial, with judgment entered for Meta. The court rejected the FTC’s proposed “personal social networking” market, holding that Meta faces competition from other social media platforms. The court declined to infer monopoly power from Meta’s profits and found that the FTC had not shown any increase in the price of Meta’s apps.
• Trial counsel in an antitrust win, with a federal jury awarding $147.4 million (before trebling) to Innovative Health after finding that Johnson & Johnson subsidiary Biosense Webster illegally tied the provision of clinical support services to the purchase of heart catheters and monopolized the markets for its catheters through various anticompetitive means.
• As co-lead MDL and class counsel, achieved a $630 million settlement against CDK Global and Reynolds & Reynolds for restricting auto dealer data access, an outcome expected to return 82% of damages to class members.
• Represented the National Credit Union Administration (NCUA) in claims arising from the sale of faulty mortgage-backed securities. With the firm as lead counsel and after winning five appeals in four different circuit courts, NCUA recovered more than $5.1 billion from Wall Street banks in these cases.

• Firm ranking, Appellate, General Commercial Litigation, Telecom, and individual rankings for Michael Kellogg, Mark Hansen, David Frederick, Scott Angstreich, Derek Ho, and Aaron Panner, 2025—Chambers USA
• Behavioral Matter of the Year: Americas, 2026—Global Competition Review.
• Elite Trial Lawyers (Technology): Derek Ho, Michael Nemelka, Daniel Dorris, and Aaron Panner; Young Lawyer of the Year (Litigation): Alejandra Ávila, 2025—The American Lawyer.
• Derek Ho and Michael Nemelka, Unrivaled Litigators, and Bradley Oppenheimer, They’ve Got Next: The 40 Under 40, 2025—Bloomberg Law.
• Outstanding Antitrust Litigation Achievement in Private Practice, 2025—American Antitrust Institute