Oleg Chayka

Oleg Chayka

Advisor, Tax

Contact Information


tel: 416.862.4201



Areas of Expertise

Bar Admission

Kyiv, Ukraine, 2000


Kyiv Institute of International Relations (Ukraine)

ESC CERAM Business School (now SKEMA) (France)

Canadian Institute of Certified Public Accountants (CICA) (Canada)


English, Ukranian, Russian

Oleg is currently working with Osler on secondment from the tax group at the Ukrainian law firm Arzinger. Oleg is a recognized taxation expert, including tax disputes, transactional and international taxation who has worked in senior positions in Canada, Malta and Ukraine, and has experience advising on international and national law. As a leading expert on taxation, Oleg has participated in landmark cases resolved in international arbitration courts.

In Canada, Oleg worked in a leading global accounting firm, where, amongst others, he was involved in developing and implementing effective international taxation solutions.

In Malta, Oleg was involved in implementing ATAD I and other BEPS-related initiatives, managing high-profile client accounts and attracting clients from the CIS region.

In Ukraine, Oleg was responsible for tax planning and structuring of investments in Ukraine and from Ukraine, M&A tax projects, corporate reorganizations, business project financing as well as tax disputes.

  • The Legal 500: Leading expert on transactional taxation in Ukraine (2018)
  • International Tax Controversy Guide (from World Tax and International Tax Review): Named one of the best lawyers in tax disputes in Malta (2019) and Ukraine (2020)

  • Assistance to Ukrainian mothers with children to flee the war in Ukraine and to get relocated to Malta and other EU jurisdictions

  • Co-Chairman of the Tax Committee of the American Chamber of Commerce in Ukraine nine times in a row
  • Member of the working groups of the Parliament of Ukraine on tax reform issues

Ukraine Incentivizes Investments In and Operation of IT-related and R&D Projects, CEE Legal Matters (February, 2022) https://ceelegalmatters.com/briefings/19155-ukrain-incentivizes-investments-in-and-operation-of-it-related-and-r-d-projects

Legal and tax aspects of M&A projects, CFO Club, Kyiv, Ukraine (February, 2022) https://www.facebook.com/media/set/?set=a.2790375737922233&type=3

How to pay less Ukrainian taxes on foreign-source income, The Page (February, 2022) https://thepage.ua/ua/experts/yak-zekonomiti-na-podatkah-v-ukrayini-pri-otrimanni-inozemnih-dohodiv

Ukraine: Employee Incentives, The Legal 500 (January, 2022) https://www.legal500.com/guides/chapter/ukraine-employee-incentives/

Management of tax, regulatory and compliance risks in connection with investments abroad, XX Annual CFO Forum, Kyiv, Ukraine (October, 2021) https://cfo.ua/all_speakers

Tax amnesty, CEO Club, Kyiv, Ukraine (July, 2021)

Tax changes 2021 and their impact on transactions with non-residents, CEO Club, Kyiv, Ukraine (April, 2021)

Lecturer, International Tax Course, Tax Academy, Ukraine (October, 2020)