27.2.2024

Mergers and Acquisitions: ESG Due Diligence requires legal expertise

Nowadays, a successful company must have a strategic approach to sustainability work, accounting for the special characteristics of the company’s business. In the coming years, sustainability will permeate the strategy, business practices and value chains of companies, which are required to increase their efforts to mitigate their adverse environmental and human rights impacts.

A failure in sustainable transition or in meeting the stakeholders’ and investors’ expectations can have long-term consequences for the company. This means that sustainability cannot be ignored in mergers and acquisitions either. ESG due diligence reviews have become an increasingly important and critical part of M&A in recent years.

Sustainability is deemed to be one of the factors contributing to the success of modern business operations and ensuring the continuity of operations, and it is therefore strongly linked to the company’s value creation. In its most concrete form, ESG work means that practical tasks are carried out in accordance with the company’s policies and instructions. ESG due diligence reviews (ESGDD) dive into the practical aspects and maturity level of the company’s sustainability work by assessing ESG-related risks and possibilities.

There are different options for carrying out an ESGDD review. At the same time as the European regulatory framework of corporate sustainability is taking shape at a rapid pace, ESGDD reviews are becoming an essential part of the entire legal due diligence.

ESGDD requires legal expertise

In the everyday life of companies, sustainability is strongly connected with compliance, and in M&A situations the parties seek a legal point of view for handling compliance matters. The observations of a ESG due diligence review may become significant for the completion of an M&A transaction and for its terms and conditions, which means that a due diligence review increasingly adds elements to the purchase agreement and M&A insurances.

The risks observed in ESGDD are often legal questions that are related to various areas, such as environmental law, occupational safety or employment law. As the observations are associated with great financial and legal risks, going through them requires considerations by specialists who are familiar with the field and have deep legal expertise. For example, questions related to environmental permits and environmental liability require the perspective of an experienced environmental lawyer.

ESG due diligence and legal due diligence work have clear synergies because both use the same material in many respects. Even though sustainability reporting in accordance with the new directive ensures that companies report their sustainability using figures assured by auditors, ESGDD is much more than just assuring figures to be reported as it delves deeper into the company’s practical sustainability work and risk management.

Successful ESGDD supports the company’s strategy

A word of advice: even an experienced compliance expert carrying out ESG due diligence work must understand the practical sustainability work. In an ideal situation, a high-quality due diligence review strengthens understanding of ESG questions as part of other compliance work. Companies benefit most from DD that finds common points with the company’s sustainability targets and its strategy because, in addition to the usual deal breakers, a due diligence review provides information on what kinds of investments the object of purchase will require in the coming years. That is why companies should choose an ESGDD partner with extensive knowledge of M&A, sustainability as well as compliance work.

See also:

Anna Kuusniemi-Laine and Lia Heasman to expand C&S’s corporate sustainability service

Corporate sustainability will extend to value chains – four tips for implementing due diligence duty

Case law will ultimately clarify the interpretation of the new CSDD Directive

Latest references

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Case published 10.6.2026
castren snellman general atlantic iceye
We advised General Atlantic as the lead investor on ICEYE’s EUR 1 billion series F funding round, valuing the company at over EUR 10 billion. ICEYE raised EUR 450 million (USD 520 million) in a primary Series F funding round led by General Atlantic. Additional investors included Solidium, Tesi, Varma, Ilmarinen, Lifeline Ventures, Nokia, Qatar Investment Authority (QIA) and TCV. Together with a secondary placement, the total fundraising exceeds EUR 1 billion. ICEYE is the world leader in sovereign intelligence from space, providing continuous monitoring capabilities to detect and respond to changes in any location on Earth. The company operates the world’s largest and most advanced Synthetic Aperture Radar satellite constellation. General Atlantic is a leading global investor with more than four and a half decades of experience providing capital and strategic support for over 885 companies throughout its history. As of March 31, 2026, General Atlantic manages approximately USD 126 billion in assets across its investment strategies. We advised General Atlantic on this transaction in collaboration with the international law firm Paul, Weiss, Rifkind, Wharton & Garrison.
Case published 9.6.2026
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
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.
Case published 13.4.2026