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Shannon L. Ernster


(213) 576-5072
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Los Angeles
633 West Fifth Street
52nd Floor
Los Angeles, CA 90071

San Diego
101 W. Broadway
Suite 2000
San Diego, CA 92101

5 Park Plaza
Suite 1100
Irvine, CA 92614


J.D., University of California Hastings College of the Law, 2009

B.A., Art History, University of Virginia, 2002

Shannon L. Ernster is Partner in the Insurance and Health Care practice groups in the Los Angeles office of GRSM. Shannon's practice involves the litigation of group and individual life, health, and disability claims, and employee benefit disputes brought under ERISA.  However, her practice is focused primarily on the litigation of health care claims and disputes between health plans and health care providers.
Shannon defends managed care entities and insurance companies in disputes involving claims for breach of contract, bad faith, fraud, unfair competition, and other extra-contractual relief.  She also represents employee welfare benefit plans and administrators in disputes involving employee benefits and breach of fiduciary duty claims.  Shannon litigates throughout California, and she has extensive experience handling all aspects of litigation in state and federal court, as well as arbitrations.  Shannon's experience, knowledge of the law, and creativity enable her to successfully advocate for her clients in all phases of litigation, and to counsel her clients regarding developments in the actively evolving health care industry.
Prior to joining GRSM, Shannon practiced in the specialty of professional liability litigation, including legal malpractice, dental malpractice, and real estate professional liability matters.


  • California
  • United States District Courts, California

Community Involvement

  • Junior League of Pasadena