Kerttu Mettälä

Associate, Master of Laws

Services

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I advise our domestic and international clients on private equity, fund-related matters, and mergers and acquisitions.

Prior to my current role, I have gained work experience as a trainee at Castrén & Snellman, the Finnish Patent and Registration Office, and another Finnish law firm.

I hold a Master of Laws degree from the University of Turku. During my studies, I gained international experience while studying at the University of Alicante in Spain.

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Latest references

Aurevia and Labquality – Strategic reorganisation

We advised Aurevia Oy, a portfolio company of French private equity sponsor Mérieux Equity Partners, in a strategic reorganisation that involved splitting Aurevia and its parent companies into two independent groups of companies and reorganisation of its existing debt-financing arrangements. Following the reorganisation, the newly formed Aurevia continues as a leading provider of Contract Research Organization (CRO) and Quality Assurance and Regulatory Affairs (QARA) services, while the newly formed Labquality focuses on delivering External Quality Assessment (EQA) services. Aurevia serves operators in the medical devices, in vitro diagnostics and pharmaceutical sectors. Labquality’s customers include clinical laboratories and social and healthcare organisations. The reorganisation positions Aurevia and Labquality to allocate investments more effectively, accelerate growth within their respective customer segments, and respond to evolving market and client needs. The transaction was implemented through multiple parallel demergers and required comprehensive legal and tax structuring across several jurisdictions. Our team supported Aurevia throughout the planning and implementation phases, covering corporate, tax, employment law, and regulatory matters, as well as the optimisation of each group’s financing structure.

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.

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.

Taaleri – Acquisition of a majority stake in Nordic Science Investments

We are acting as legal adviser to Taaleri Plc on its acquisition of a 51 per cent ownership stake in Nordic Science Investments Oy (NSI), marking Taaleri’s expansion into deeptech-driven venture capital. Through the transaction, Taaleri broadens its private equity offering into early-stage venture capital funds as well as the commercialisation and scaling of research-driven innovations. NSI is a Finnish venture capital fund manager operating across the Nordic and Baltic regions, focusing on early-stage investments in research- and science-based technologies. Its portfolio companies develop, among other things, health technologies, life sciences, advanced materials and AI-driven solutions. In addition to providing growth capital, NSI supports spin-out companies with strategic guidance, access to networks and assistance in building teams during the early phases of business development. NSI’s first fund, the EUR 45 million NSI Nordic Science I Ky, was established in 2024 and has to date invested in 22 early-stage companies in Finland, Sweden and the Baltic countries. Taaleri is a specialist in investments, private asset management and non-life insurance, with a strong position in renewable energy, bioindustry and housing investments as well as credit risk insurance. Taaleri has EUR 2.7 billion of assets under management in its private equity funds, co-investments and single-asset vehicles, employs approximately 130 people and is listed on Nasdaq Helsinki. The founders of NSI will continue in their operational roles following the transaction. The completion of the transaction is subject to approval by the FIN-FSA.

Finnish Centre for Pensions – Information design workshop

We delivered two information design workshops for the legal department of the Finnish Centre for Pensions, with participants from both legal and other professional backgrounds. In the sessions, we applied the principles of legal design thinking to the Finnish Centre for Pensions’ field of operation and background materials, also utilising AI as a design tool. The participants found the tailored training highly useful and commended the trainers for their in-depth familiarisation with the Centre’s opinion drafting process and operating environment. As a result of the workshops, our experts proposed a new structural and linguistic model for the legal department of the Finnish Centre for Pensions for drafting opinions and guidelines. The proposal was well received as clear and applicable to the participants’ everyday work. In addition, we presented tailored AI use cases to support experts, allowing for a more efficient AI-assisted way of working. Our experts who delivered the workshops combined their legal expertise with their leading experience in legal design. The participants appreciated this versatile expertise, which enabled a knowledgeable, creative and applied approach to legal writing. ‘C&S created a well-structured training tailored to our needs, providing clear direction for our organisation and concrete takeaways for our experts in their day-to-day work,’ says Mari Kuunvalo, Head Of the Legal Department at the Finnish Centre for Pensions.

Aktia Bank – EUR 80 million AT1 bond

We advised Aktia Bank Plc on the issuance of an EUR 80 million Additional Tier 1 (AT1) bond. The bond pays a fixed interest rate of 6.75 per cent semi-annually. The bond is perpetual, and Aktia has the right to redeem or repurchase it in accordance with the terms of the bond, subject to certain conditions. The bond was issued on 1 April 2026. In addition, we assisted Aktia in listing the bond on the Nasdaq Helsinki Ltd stock exchange. For the listing, we prepared Finland’s first EU Follow-on prospectus for a bond. The EU Follow-on prospectus was introduced on 5 March 2026 with an update to the Prospectus Regulation (EU) No. 2017/1129. The EU Follow-on prospectus is a new type of prospectus that can be used, among others, by issuers whose securities have been admitted to trading on a regulated market continuously for at least the 18 months preceding the offer to the public or the admission to trading on a regulated market of the new securities. A follow-on prospectus is simpler than a so-called traditional prospectus, and it is intended to avoid repeating information that the issuer has already disclosed. Nordea Bank Abp acts as the sole structuring advisor for the issue of the Notes. Nordea Bank Abp, Danske Bank A/S and ABN Amro Bank N.V. act as the lead managers for the issue of the Notes.

Downing – Acquisition of the entire share capital of Tornionlaakson Voima

We advised UK-based investment company Downing in its acquisition of the entire share capital of Tornionlaakson Voima Oy. Tornionlaakson Voima owns three hydropower plants in the Tengeliönjoki river system – the Portimokoski power plants in Ylitornio, the Jolmankoski power plants in Raanujärvi and the Kaaranneskoski power plants in Sirkkakoski. The power plants produce a total of approx. 45 gigawatt-hours of electricity per year. Tornionlaakson Voima’s daily operations will continue normally, and the transaction will not affect customers. The consummation of the transaction is subject to the approval of the Ministry of Economic Affairs and Employment. Downing has over 35 years’ experience in providing a wide range of investment solutions to the needs of institutional investors, advisers and retail investors. The company manages over £2 billion in assets in both the private and public markets and its current hydro power portfolio includes approx. 50 hydro power plants in the Nordics.

CapMan Infra’s portfolio company Koiviston Auto Group – EUR 300 million refinancing

We advised CapMan Infra’s portfolio company Koiviston Auto Group, Finland’s largest bus operator, in a finance arrangement in which it completed an approximately EUR 300 million refinancing. The transaction consists of the refinancing of the Group’s existing senior debt and secures long-term growth financing to support the Group’s continued investments in its rapidly expanding electric bus fleet. The financing package has been provided by a group of lenders consisting of Nord/LB, ABN AMRO, Edmond de Rothschild, LBP AM and Siemens. The transaction strengthens Koiviston Auto’s funding base and provides significant flexibility to execute the company’s growth strategy focused on sustainable public transportation. CapMan Nordic Infrastructure I acquired Koiviston Auto in December 2021 to support its expansion and operational development. The Group now serves communities nationwide and is at the forefront of the transition to zero-emission public transport in Finland. It operates approximately 300 electric buses, with more than 50 additional electric buses expected to be deployed into traffic during 2026, further accelerating the electrification of its fleet. “The successful completion of this refinancing marks an important milestone for Koiviston Auto Group,” says Henrik Mikkola, CEO of Koiviston Auto Group. “The strong support from a diversified group of high-quality lenders underlines the robustness of our business and our long-term strategy. This financing allows us to continue investing in electric mobility and to provide reliable, sustainable and high-quality public transport services across Finland.” “Koiviston Auto Group plays a key role in the green transition of public transportation in Finland,” comments Ville Poukka, Managing Partner at CapMan Infra. “This refinancing significantly strengthens the company’s financial platform and enables continued investments into electric buses at scale. We are pleased to see strong lender confidence in the company’s strategy, operational performance and long-term growth prospects.”

Get to know our other experts in the field

Jarno Tanhuanpää

Managing Partner

+358 50 560 1130 jarno.tanhuanpaa@castren.fi

+358 40 527 6105 karlo.siirala@castren.fi

Tuomas Honkinen

+358 40 760 1565 tuomas.honkinen@castren.fi

Freja Väyrynen

+358 50 380 0579 freja.vayrynen@castren.fi

Jussi Mäkikangas

Senior Associate

+358 45 128 4070 jussi.makikangas@castren.fi

Anton Helanterä

+358 45 788 18000 anton.helantera@castren.fi

+358 40 032 6436 lauri.martin@castren.fi

Helmi Puustinen

+358 50 501 7120 helmi.puustinen@castren.fi

Aleksi Uusitalo

+358 45 782 04205 aleksi.uusitalo@castren.fi

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