Sonja Hänninen

Senior Associate / Helsinki

About Sonja

Sonja advises our clients primarily on assignments that relate to banking and finance. She has extensive experience in advising financial institutions, sponsors, and borrowers on both domestic and cross-border financing and debt capital markets transactions, including acquisition financing, real estate financing, and general corporate lending.

During her career, Sonja has e.g. worked as a visiting lawyer in the Corporate Loans and Transaction Banking division of OP Corporate Bank plc.

Service areas


  • Senior Associate, Borenius, 2023–
  • Legal Counsel (Secondee), OP Corporate Bank plc, 2021–2022
  • Senior Associate, Castrén & Snellman Attorneys Ltd, 2020–2023
  • Senior Associate, Dittmar & Indrenius Attorneys Ltd., 2020–2020
  • Associate, Castrén & Snellman Attorneys Ltd, 2016–2020


  • Bar Admission, 2020, Helsinki, Finland
  • Master of Laws, 2015, University of Helsinki


  • Finnish, English