Peter Simshauser has a diverse litigation practice concentrating on complex commercial cases. His experience includes trials, arbitrations and mediations, and arguments before federal and state appellate courts on behalf of clients in various business sectors, such as financial services, investment banking, insurance and environmental matters.


Mr. Simshauser has represented clients in various areas of law such as securities, complex contract disputes, insurance bad faith, environmental, mass and toxic torts, and Lanham Act and state law unfair trade practices. In addition, he has advised clients in pending or threatened litigation, administrative proceedings, corporate transactions and internal investigations.

His representations have included:

  • Fremont Investment and Loan in a victory in Massachusetts Supreme Judicial Court in a first impression case brought by a plaintiffs attorney who argued that the Massachusetts version of the Freedom of Information Act required that information provided to the government in a federal securities case be made available to members of the public;
  • Putnam Investments in an interlocutory appeal that reversed a Madison County, Ill. court’s refusal to dismiss three putative class actions involving allegations of improper market timing activities. A three-judge panel of the Fifth District Appellate Court held that the complaints alleged misrepresentations or omissions and were therefore precluded by the federal Securities Litigation Uniform Standards Act of 1998;
  • The independent trustees of an asset management company in the dismissal of a securities class action suit in the U.S. District Court for the Southern District of New York in connection with allegations that the offering materials of one of the mutual funds that invested in asset-backed and mortgage-related securities misled investors;
  • Progress Software Corporation in the settlement of two shareholder derivative cases in Massachusetts state court and one in Massachusetts federal court alleging breach of fiduciary duty in connection with allegations of stock option backdating; and
  • Biogen Idec Inc. in three shareholder derivative actions in Delaware, California and Massachusetts, and one putative securities class action in Massachusetts alleging that Biogen violated sections of the Securities Exchange Act of 1934 in statements it made regarding the safety and marketability of its multiple sclerosis drug, Tysabri. All three derivative actions were dismissed, and the dismissal of the putative securities fraud class action was affirmed by the U.S. Court of Appeals for the First Circuit;
  • A subsidiary of 21st Century Fox in numerous legacy environmental matters arising from a partial ownership interest in a former pesticide manufacturer; and
  • Underwriters of both stock and loan securities who were sued in state and federal courts for allegedly misleading offering documents.

Mr. Simshauser is a member of the selection committee for the Skadden Fellowship Program, which annually awards more than 25 fellowships in public interest law to graduating law students and outgoing judicial clerks.



  • J.D., Harvard Law School (1983) (cum laude)
  • B.S., University of Illinois (1980) (highest honors)
  • B.A., Augustana College (1979) (summa cum laude)


  • Massachusetts


  • Law Clerk, U.S. District Court, District of Northern Illinois (1983-1985)

Peter Simshauser