Oleksii Kostromov

Oleksii Kostromov

Of Counsel

Oleksii Kostromov is Of Counsel with the firm’s Corporate and M&A and International Dispute Resolution practices.

He is responsible for advising international and domestic clients on a wide range of issues arising in the area of corporate and commercial law, including handling cross-border M&A and corporate finance transactions, equity and debt offerings, private equity and joint venture deals, drafting and negotiating security documentation for cross-border lending transactions.

Oleksii has extensive experience of matters involving national and complex cross-border litigation and arbitration, including acting as an arbitrator. He deals with commercial litigation and arbitration and manages disputes relating from shareholder agreements and sales and purchase agreements to debt enforcement, public procurement and public contracts.

As part of his pro bono activities, Oleksii has been acting as an arbitrator at the Annual Willem C. Vis International Commercial Arbitration Moot in Vienna (Austria) since 2006.

Professional experience

Oleksii Kostromov enjoys a stellar reputation on the market for his profound expertise in the energy and natural resources sector. Prior to joining Hillmont Partners, he acted as a legal advisor to a major oil and gas project in one of the Baltic States, assisted an EU-funded project with drafting the new Subsoil Code of Ukraine, as well as with developing laws and regulations on minimum stocks of crude oil and petroleum products.

Oleksii managed legal advisory support for the Association of Gas Producers of Ukraine and was responsible for drafting legislative proposals to improve the legal environment of the domestic gas market, developing compliance procedures applicable to the oil and gas industry. He had earlier headed the legal function at DTEK, Ukraine’s largest energy holding company, where he advised on transactional and regulatory projects covering the company’s conventional and alternative energy resources. His experience in international consultancy and legal services includes working for Clifford Chance as well as Salans.


  • McGill University (Montreal, Canada), LL.M. (Master of Laws);
  • Kyiv Taras Shevchenko University, Institute of International Relations, Specialist in International Law.

Awards and Recognition

  • Senior Expert, included in the Roster of Experts of the Energy Community and its Secretariat;
  • Honorary Fellow of the of the Association of Fellows and Legal Scholars of the Center for International Legal Studies (Salzburg).