Washington, DC, January 23, 2026— Lawdragon has named six Phillips & Cohen partners –Peter Chatfield, Stephen Hasegawa, Erika Kelton, Colette Matzzie, Sean McKessy, and Claire Sylvia—to its 2026 “500 Leading Lawyers in America” list.
Whistleblower attorneys Chatfield, Hasegawa, Kelton, Matzzie, McKessy, and Sylvia have achieved significant successes representing whistleblowers, winning large settlements, and securing significant rewards for their whistleblower clients.
- Peter Chatfield (retired) has three decades of experience representing whistleblowers, including a qui tam case against HCA, one of the nation’s largest healthcare providers, which was the basis for a majority share of HCA’s $881 million settlement with the government. Chatfield helped secure a $425 million settlement against Cephalon, Inc. for its off-label marketing of Fentanyl-based pain medications and a $53.68 million settlement with Paragon Systems for allegedly engaging in an unlawful scheme to obtain security officer service contracts set aside by the Department of Homeland Security to be awarded to small businesses.
- Stephen Hasegawa specializes in the False Claims Act, including whistleblower cases involving healthcare, defense, aerospace, financial services, and government procurement. Among his successes, Hasegawa secured a settlement against Office Depot for $68.5 million, where more than 1,000 California cities, counties, school districts, and other government entities were allegedly overcharged for office supplies. Hasegawa also obtained a $22.8 million settlement against Linde GmbH and Linde Engineering North America for evading US customs duties and a $75 million settlement with a subsidiary of Community Health Systems Inc. and three of its New Mexico hospitals for allegedly donating funds to New Mexico counties as a way to improperly increase federal payments.
- Erika Kelton is an internationally recognized whistleblower lawyer with more than three decades of experience representing whistleblowers. Her cases have recovered billions, including securing the most Dodd-Frank awards for her clients through the SEC and the CFTC whistleblower programs. She won a record-setting settlement from GlaxoSmithKline for $3 billion and secured a $40 million reward from the SEC for her whistleblower clients. In 2025, Kelton helped secure a $1.3 million SEC award for a whistleblower client.
- Colette Matzzie’s whistleblower cases against healthcare companies and government contractors have returned hundreds of millions of dollars back to government programs. She obtained government intervention against five electronic health record companies, including a record-setting settlement against eClinicalWorks, alleging that it had falsely represented its compliance with federal requirements designed to ensure patient safety, and paid kickbacks in violation of federal law. That case settled for $155 million. In 2023, Matzzie secured a $31 million settlement with NextGen Healthcare to settle federal False Claims Act allegations.
- Sean McKessy represents clients under the SEC, CFTC, and other regulatory whistleblower programs. McKessy secured a client a $20 million award from the SEC in 2022 and helped secure a client a $9 million award in 2023. Prior to joining P&C, he served as the first Chief of the SEC Office of the Whistleblower and was the principal architect of the SEC whistleblower program. The SEC recovered more than $500 million in sanctions as a result of whistleblowers’ information and assistance during his tenure at the agency.
- Claire Sylvia is the author of a leading treatise on the False Claims Act and has represented whistleblowers in “qui tam” cases involving healthcare fraud, defense contractor fraud, and cybersecurity issues. In 2024, Sylvia helped secure a $90 million False Claims Act settlement against Humana for allegedly submitting fraudulent bids to the Centers for Medicare & Medicaid Services for Medicare Part D prescription drug contracts, significantly overcharging the government.
Phillips and Cohen’s attorneys represent whistleblowers under the False Claims Act (FCA), the Securities and Exchange Commission (SEC), the Commodity Futures Trading Commission (CFTC), and Anti-Money Laundering (AML) whistleblower programs.
This is the 18th year in a row that Lawdragon has recognized Phillips & Cohen partners in its annual list of the “500 Leading Lawyers in America” for their accomplishments representing whistleblowers. Three Phillips & Cohen partners have been named to Lawdragon’s Legends list, Mary Louise Cohen, Erika Kelton, and Colette Matzzie.
Phillips & Cohen is the most successful law firm representing whistleblowers, with recoveries from our cases totaling over $13 billion. Phillips & Cohen’s roster includes former federal prosecutors, the first head of the SEC Office of the Whistleblower, the former director of the CFTC’s Whistleblower Office, the attorney with the most awards under the Dodd-Frank whistleblower programs, the author of a leading treatise on the False Claims Act, and attorneys with decades of experience representing whistleblowers. Contact us.