Jesper Kostiainen

Managing Associate
+358 9 2288 4287
+358 40 742 0475
Mari Kooli

Assistant's telephone:

+358 9 2288 4456

Assistant's e-mail:


Jesper specialises in mergers and acquisitions as well as private equity transactions. He also advises clients in energy and infrastructure related deals. In addition to offering corporate and contract law advice, Jesper also has several years’ experience in financing and real estate-related transactions.

Jesper worked as a foreign associate at the private equity practice of Kirkland & Ellis in New York during 2017–2018.  In addition, Jesper’s international experience also includes studying economics at Cornell University and law at the University of Gothenburg for one semester.


  • Counsel to YIT in the sale of its Nordic paving and mineral aggregates businesses to Peab for EUR 280 million

  • Counsel to Scandic Hotels Group in its EUR 114.5 million acquisition of Restel's hotel operations in Finland

  • Counsel to Lemminkäinen Corporation in the combination of Lemminkäinen Corporation and YIT Corporation through a statutory merger

  • Counsel to SUSI Partners AG in its acquisition of the Tetrituuli Wind Farm in Finland from Ilmatar Windpower Plc

  • Counsel to Hartwall Capital Oy Ab in its acquisition of SUEZ Suomi Oy

  • Counsel to SoftBank and its affiliates in the sale of their entire 72.2% stake in Supercell, a Finnish leading mobile game maker, to Tencent, a Chinese internet company, in a transaction valuing Supercell’s equity at USD 10.2 billion

  • Counsel to Uponor in establishing an Intelligent Water Sensing  Technology JV with Belkin International in the U.S. and Europe

  • Counsel to Patria and its shareholder in the sale of 49.9% of the shares in Patria Oyj to Kongsberg Defence & Aerospace AS

  • Counsel to EQT Infrastructure Limited in its sale of Adven Group to a consortium comprising of AMP Capital Investors and Infracapital Partners II

  • Counsel to Valmet in its EUR 340 million acquisition of the process automation systems business from Metso

  • Counsel to Ratos in its EUR 97 (enterprise value) million acquisition of approximately 67 % of Ledil from the company founders

  • Finnish counsel to SoftBank Corp. and GungHo Online Entertainment, Inc., Japanese corporations, in their USD 1.53 billion acquisition of a 51% stake in Supercell Oy, a Finnish online gaming company
  • Finnish counsel to Microsoft Corporation in its EUR 5.44 billion acquisition of Nokia Devices & Services from Nokia Corporation
  • Counsel to Triton in the acquisition of Suomen Lähikauppa Oy
  • Counsel to Vaaka Partners Oy in the acquisition of Solita Oy
  • Counsel to EQT Infrastructure Fund in its EUR 200 million acquisition of Fortum Energiaratkaisut Oy and Fortum Termest AS from Fortum Corporation


  • Member of the Finnish Bar Association


  • Managing Associate, Hannes Snellman, 2016-
  • Foreign Associate, Kirkland & Ellis (New York), 2017–2018
  • Senior Associate, Hannes Snellman, 2012
  • Secondee, SRV Group Plc, 2010
  • Associate Lawyer, Hannes Snellman, 2008
  • Master of Laws, University of Helsinki, 2008