Katherine M. Turner

Katherine Turner Photo

Katherine Turner focuses her practice on complex civil litigation and government and internal investigations.  She has represented corporations, professional firms, and individuals in a range of federal and state cases, at both the trial and appellate levels, and in arbitration before AAA, JAMS, and FINRA.  Katherine serves as Co-Chair of the firm’s Accountant Liability practice group.  She has extensive experience in defending accounting firms in professional liability and regulatory matters, including work for three of the Big Four firms and a prominent national accounting firm.

Katherine also has significant experience in representing clients in congressional investigations, including representation of Secretary Hillary Rodham Clinton before the House Select Committee on Benghazi and a recent representation of a government official in a matter before the House Committee on Oversight and Reform.  In litigation matters, her practice has encompassed cases in several substantive areas, including securities litigation and commercial contract disputes.

Benchmark Litigation has recognized Katherine as a “Litigation Star” in the areas of commercial litigation and white collar criminal defense, 2017-2022, and among the “Top 250 Women in Litigation” for the last six years. 

Katherine was born and raised near Philadelphia, Pennsylvania and graduated from Georgetown University, summa cum laude, in 2001.  She received her J.D., cum laude, from the Harvard Law School, where she was an editor of the Harvard Law Review.  She joined Williams & Connolly in 2005, after serving as a law clerk to the Honorable Bruce Marshall Selya of the United States Court of Appeals for the First Circuit.  Katherine is a Co-Chair of the firm’s Women’s Initiative and the Chair of the firm’s Intake Committee.

Representative Experience

Though all cases vary and none is predictive, Katherine's experience includes:

  • Current representation of Big Four accounting firm in arbitration related to audits of investment funds.
  • Current representation of national accounting firm in professional liability litigation concerning audits of investment funds.
  • Current representation of national accounting firm and foreign Big Four firm in PCAOB investigations.
  • Current representation of national accounting firm and Big Four firm in SEC investigations.
  • Successful representation of individual in Title IX hearing, resulting in a finding of not responsible.
  • Ongoing representation of Fortune 50 technology company in pre-litigation analyses of commercial contract and employee disputes.
  • Successful representation of Big Four accounting firm in two-year PCAOB investigation related to audits of lending company, resulting in no action taken against firm or its auditors.
  • Representation of national accounting firm in successful resolution of professional liability cases involving audits of a health insurance company and an employee benefit plan.
  • Successful representation of national accounting firm in defense of professional liability claims arising from audits of funds invested in the Petters Ponzi scheme, including prevailing at summary judgment against ~$1 billion claim brought by funds’ bankruptcy trustee and defeating two investor suits at the motion-to-dismiss stage.
  • Representation of Secretary Hillary Rodham Clinton before the House Select Committee on Benghazi and in connection with matters concerning her e-mail use.
  • Representation of high-profile non-profit organization in internal investigation of board member’s personal conduct.
  • Representation of Fortune 50 healthcare company in successful resolution of securities class action litigation involving ~$900M in alleged damages.
  • Successful representation of several interdealer brokers in disputes with their former employer in series of FINRA arbitrations.
  • Successful representation of technology company in JAMS arbitration involving alleged violations of trademark agreement, resulting in judgment in favor of client on all claims and an award of attorney’s fees, following full merits trial.
  • Successful representation of Big Four accounting firm in appeal of trial verdict in which the jury had found liability to a non-client arising from an audit.




"Local Litigation Star," Benchmark Litigation, 2017-2022

“Top 250 Women in Litigation,” Benchmark Litigation, 2016-2021

“40 & Under Hot List”, Benchmark Litigation, 2017-2020

Selected to Washington, D.C. “Rising Stars” list, Super Lawyers, 2014-2019


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