Leo Hynninen

Associate, Master of Laws

Services

  1. Private M&A
  2. Private Equity

Contact details

I advise our clients on domestic and cross-border mergers and acquisitions.

I joined Castrén & Snellman as an associate in May 2025. Before graduating, I worked as a trainee at two other law firms.

I hold a Master of Laws degree from the University of Helsinki.

Latest references

Scanreco – Acquisition of CrossControl
We acted as Finnish counsel to Scanreco in its acquisition of CrossControl. Mannheimer Swartling (Sweden) acted as lead counsel for Scanreco. CrossControl, founded in Sweden, is a high-tech supplier of advanced display computers and central vehicle computing solutions for industrial vehicles and machines. Scanreco is a world leading supplier of professional radio remote control systems to international machinery, heavy equipment, and crane manufacturers. The combined group comprises approximately 600 employees and generates annual revenue of around SEK 1.4 billion.
Case published 5.5.2026
General Catalyst – ICEYE’s USD 150 Million Series E Funding Round
We advised General Catalyst as lead investor on ICEYE’s EUR 150 million series E funding round, valuing the company at EUR 2.4 billion. ICEYE is the world leader in synthetic aperture radar (SAR) satellite systems and operates the largest SAR constellation globally. Its technology delivers objective, near real-time Earth observation in any weather or light conditions, enabling governments and institutions to manage risks and respond faster. General Catalyst is a global investment and transformation company, partnering with leading entrepreneurs to build toward global resiliency and applied AI. Its portfolio includes companies such as Airbnb, Snap, Stripe, Mistral AI, Hubspot, Anduril, Helsing and Legora. We advised General Catalyst on this transaction in collaboration with the US law firm Goodwin. 
Case published 8.12.2025
Merger of Oomi and Lumme Energia
We are acting as the joint legal advisor to Oomi Oy and Lumme Energia Oy in a transaction whereby Lumme Energia will merge with Oomi. As from the completion of the merger, the combined entity will be the largest electricity retail and service company in the Finnish market. In 2024, Oomi reported a turnover of EUR 373.9 million and had approximately 110 employees. Lumme Energia’s turnover for the same year was approximately EUR 314.6 million and it had approximately 50 employees. The transaction is primarily driven by the recent developments in the electricity market and the strategic goal to develop competitive products and services. Another key objective is to further enhance the customer experience, which is a shared value between the two companies. As a result of the merger, Lumme Energia’s customers will transfer to Oomi, and Lumme Energia will become one of Oomi’s shareholders. The completion of the transaction is subject to an approval by the Finnish Competition and Consumer Authority.
Case published 29.8.2025
G&W Electric – Acquisition of Safegrid
We advised G&W Electric with its acquisition of Safegrid Oy, a leading provider of intelligent grid monitoring solutions based in Finland. The acquisition accelerates G&W Electric’s long-term strategy to integrate intelligent monitoring and predictive analytics into its power distribution portfolio, strengthening its offering to utility customers worldwide. Founded in 1905 and headquartered in Bolingbrook, Illinois, G&W Electric is a global leader in innovative power grid solutions, with a presence in over 100 countries. The company is known for advanced load and fault interrupting switches, reclosers, sensors, system protection equipment, power grid automation, intelligent grid monitoring, and transmission and distribution cable accessories. Safegrid is a Finnish technology company headquartered in Espoo, Finland. The company develops the Intelligent Grid System®, a grid monitoring solution that combines instant-on wireless sensors with advanced analytics to deliver real-time insight into grid conditions, enabling utilities to identify emerging issues, anticipate failures, and reduce outage duration across medium and high voltage distribution and transmission networks.
Case published 8.5.2026
Kiwa – Acquisition of Sertio
We advised Kiwa in its acquisition of Sertio Oy, a Finnish notified body designated by the authority in accordance with the EU Regulation on in vitro diagnostic medical devices (IVDR). Sertio provides conformity assessment services in accordance with IVDR. Kiwa is one of the world’s leading testing, inspection, and certification companies, operating in over 35 countries. 
Case published 7.5.2026
Metsäkonepalvelu – Acquisition of Junnonen Forest and the business operations of Lamerit
We advised Metsäkonepalvelu Oy in its acquisition of the entire share capital of Junnonen Forest Oy, a Finnish timber harvesting services company, and the timber harvesting services business of Lamerit Oy. The acquisition supports Metsäkonepalvelu’s growth strategy and strengthens the company’s position, particularly in southeastern Finland. Metsäkonepalvelu is a portfolio company of A. Ahlström Oy, a Finnish family-owned industrial owner. The company provides mechanical timber harvesting services to forest companies, large private forest owners, and the public sector in Finland and Sweden. Metsäkonepalvelu Group employs nearly two hundred forestry professionals.
Case published 6.5.2026
NATO Innovation Fund – Kelluu’s EUR 15 million Series A funding round
We advised the NATO Innovation Fund as lead investor on Kelluu’s EUR 15 million Series A funding round, with participation from Keen Venture Partners, Gungnir Capital, and Tesi. Kelluu is a Finnish deep tech company operating the world’s largest autonomous airship fleet. We advised NIF on this transaction alongside global law firm Latham & Watkins.
Case published 17.4.2026
Nscale – Data centre project
Castrén & Snellman advised Nscale, a European AI infrastructure company, in connection with its planned data centre project in Harjavalta, Finland. The facility will be located in the Sievari industrial area. Castrén & Snellman’s advisory role encompassed the negotiation and execution of a site securing and development agreement (SSDA) with Fortum, as well as the preliminary land sale process for the Sievari site with the Town of Harjavalta. Under the SSDA, Fortum supports the advancement of Nscale’s project development, including grid connection design and permitting.
Case published 15.4.2026

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