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Jonathan M. Sedlak

Special Counsel

Jonathan M. Sedlak

Special Counsel
New York +1-212-558-4000+1-212-558-4000 +1-212-558-3588+1-212-558-3588
[email protected]

Jon Sedlak joined Sullivan & Cromwell in 2004 and became a Special Counsel in the Firm’s Litigation Group in 2013. His practice focuses on complex financial and commercial litigation, typically on behalf of large corporations and financial institutions.  Mr. Sedlak has worked on a variety of securities, contract, fraud, derivative and intellectual property lawsuits.  He has represented financial institutions in high stakes litigation involving residential mortgage backed securities.  Mr. Sedlak has also worked on a variety of internal investigations, including investigations concerning alleged violations of securities laws and U.S. economic sanctions laws.
Most recently, he has represented FCA in both state and federal actions.  These actions, including multiple class actions, concern allegations regarding diesel emissions, as well as FCA’s EGR Cooler recall, for certain diesel vehicles.  Work for FCA has included investigations by the Securities and Exchange Commission and the Department of Justice. 
Representative Cases:

  • Barclays Bank plc in a suit brought by a hedge fund arising out of termination of a $1 billion total return swap transaction, including a complete trial victory after which the New York Supreme Court held that Barclays had no liability to the hedge fund, and the appeal, in which the Appellate Division, First Department, unanimously affirmed that trial victory
  • Barclays Bank plc and Barclays Capital Inc. in various RMBS civil litigation and regulatory matters, including in the DOJ’s high-profile FIRREA litigation.
  • Lloyds TSB Bank plc in a shareholder derivative action in New York state court relating to Lloyds’ resolution of regulatory and criminal investigations relating to economic sanctions laws. 


  • Jonathan M. Sedlak, Sovereign Debt Restructuring: Statutory Reform or Contractual Solution, 152 U. Pa. L. Rev. 1483 (2004).