Barbara W. Sonneborn

Managing Partner

Barbara Sonneborn graduated from the University of Miami School of Law in 1976 and founded the law firm with Joseph P. Metzger in 1983. The firm quickly gained recognition as one of the preeminent medical malpractice defense firms in South Florida. During her legal career, Ms. Sonneborn has served as lead counsel in numerous complex civil jury trials involving medical malpractice, products liability and general liability. In her medical malpractice work, she has successfully defended hospitals, physicians and other healthcare professionals in a wide variety of matters including, but not limited to, wrongful death, infant death, brain damage, paralysis, surgery and nursing issues. Her vast trial experience has enabled her to obtain defense verdicts for her clients throughout the State of Florida.

Ms. Sonneborn was inducted as a Fellow of the International Academy of Trial Lawyers in 2009. The Academy limits membership to 500 Fellows from the United States and only invites lawyers who have attained the highest level of trial advocacy during their legal career. She is also is a member of American Board of Trial Advocates, an elite group selected by their peers, and has received a distinguished highest rating of AV-Pre-Eminent in both legal ability and ethical standards from Martindale-Hubbell. In addition, Ms. Sonneborn has been named among “Florida’s Legal Elite” by Florida Trend Magazine and one of the Florida Super Lawyers. Ms. Sonneborn is a board certified civil trial lawyer by the Florida Bar and is board certified by the National Board of Trial Advocacy.

R. William Rutter, Jr.

Partner, of Counsel

As a graduate of the University of Florida, Frederic G. Levin College of Law in 1967. Mr. Rutter embarked on his esteemed legal career that includes County Attorney for Palm Beach County, Circuit Court Judge, Administrative Judge, Civil Division, and Chief Judge.

The Honorable Chief Judge Rutter retired from the bench in 1988 to become a named partner at the firm to begin a career in civil litigation, mediation & alternative dispute resolution. As a Florida board circuit certified mediator he earned the reputation as an outstanding arbitrator. Mr. Rutter Burt is rated AV (Peer Rated for Highest Level of Excellence) by the Martindale Hubbell attorney rating service. Mr. Rutter became of counsel with Sonneborn Rutter in 2016.

Rosemary Cooney


Rosemary Cooney is an invited member of the American Board of Trial Attorneys (ABOTA). She has an AV-Preeminent peer review rating from Martindale-Hubbell, the highest peer review rating for legal ability and ethical standards. She is also a Florida Board certified Circuit Civil Mediator.

A native of Palm Beach County, Ms. Cooney graduated with a Bachelor of Arts with Distinction from the University of Virginia in 1976. Ms. Cooney graduated from Stetson University College of Law Cum Laude in December 1978 and was admitted to the Florida Bar in May 1979. After admission, she practiced law at a prestigious Palm Beach law firm, where she became a partner/shareholder. Ms. Cooney joined Sonneborn Rutter in 1985 where she continues to be a shareholder. Over the years, Ms. Cooney has tried complex malpractice, commercial and estate litigation cases to verdict in both jury and bench trials in state courts. Currently, Ms. Cooney specializes in family law matters.

In addition to her practice, Ms. Cooney is a member of the National Committee on University Resources, and a member of the Benefactor Society for the University of Virginia. She was a founding Board member of Hospice of Palm Beach County and is a Sustainer member of the Junior League of the Palm Beaches. Ms. Cooney is also a former Board member of the Literacy Coalition of Palm Beach County.

William T. Viergever


William T. Viergever is an experienced appellate advocate with an extensive background in state and federal appeals. As a former law clerk to the Honorable Hugh S. Glickstein at the Florida Fourth District Court of Appeal, Mr. Viergever developed a unique perspective as to what appellate courts expect in appellate briefs and pleadings. He graduated from the University of Central Florida in 1993 after which he received his Juris Doctorate degree from the University of Miami in 1996. Upon the completion of his clerkship Mr. Viergever accepted a position at Sonneborn Rutter handling the firm’s appeals, complex motion practice and trial support. He is currently in charge of the Appellate Division for the firm. Mr. Viergever has successfully argued numerous appeals in the Florida District Courts of Appeal and before the Florida Supreme Court, primarily involving medical malpractice cases. His work has resulted in approximately 50 reported appellate decisions. Mr. Viergever has achieved a rating of “AV-Pre-Eminent”, the highest rating by Martindale-Hubbell, the world’s foremost lawyer rating publication.

Michael D. Burt


Mr. Burt is Board Certified as a Specialist in Civil Trial Law by the Florida Bar. He has extensive experience in all aspects of civil litigation in the State of Florida, with emphasis on medical malpractice defense on behalf of doctors, hospitals, and other health care providers. He is admitted to practice to the Supreme Court of Florida, the United States District Courts for the Middle and Southern Districts of Florida, the United States Supreme Court, the United States Court of Military Appeals and the United States Air Force Court of Military Review. He received his undergraduate Bachelor of Arts degree from The Ohio State University in 1982 (Phi Beta Kappa) and his Juris Doctor degree from the Case Western Reserve University School of Law in 1985. Mr. Burt is rated AV Pre-eminent (5.0/5.0) (Peer Rated for Highest Level of Excellence) by the Martindale Hubbell attorney rating service.

Steven M. Lury


Steven M. Lury graduated from the University of Rhode Island in 1980 and received his Juris Doctorate degree from the George Mason University School of Law in 1987. Mr. Lury has a broad array of complex and multi-party general litigation and medical malpractice litigation experience. Concentrating in medical malpractice defense, Mr. Lury is a frequent lecturer for various hospitals, physicians and insurance groups. He is a member of the Palm Beach County Bar Association and former member of The Florida Bar’s Standing Committee on Professionalism.

Mr. Lury is “AV” rated by Martindale-Hubbell. The “AV” designation represents the highest rating for legal ability and adherence to ethical standards, professional reliability, and diligence. He has represented and tried numerous cases on behalf of his clients throughout the state of Florida.

Mr. Lury is admitted to practice in all state courts within the State of Florida, the U.S. District Court for the Southern District of Florida, the U.S. District Court for the Middle District of Florida as well as the U.S. Court of Appeals for the 11th Circuit.

Mr. Lury joined Sonneborn Rutter in 2014, becoming a shareholder in 2016.