The island of Jersey launched a probe into Roman Abramovich's off-shore wealth, WSJ reported Tuesday.
In April, Jersey froze $7 billion in assets linked to the Russian oligarch following UK sanctions.
The British island, located off the coast of France, has no capital gains or inheritance tax.
Jersey, the largest of the UK's Channel Islands, has opened a probe into Roman Abramovich's off-shore wealth, according to a Tuesday report from The Wall Street Journal.
The probe will investigate potential sanctions evasion and how exactly the billionaire acquired oil company Sibneft following the collapse of the Soviet Union, people familiar with the situation told the outlet.
The deal, in which Abramovich bought Sibneft from the Russian government for $250 million and sold it back a ten years later for $13 billion, has been called "fraudulent" by Russia's former chief prosecutor. The oligarch is currently worth $12.6 billion, per the Bloomberg Billionaire's Index.
A spokesperson for the government of Jersey declined to comment on or confirm reports of a probe.
Jersey's royal court froze more than $7 billion in assets linked to the Russian oligarch in April, around a month after the UK sanctioned Abramovich. Authorities executed search warrants at locations around the island believed to be connected to Abramovich's business activities, according to a statement released last month.
While not an official part of the UK, the overseas territory must legally adhere to British sanctions. Jersey does not have a capital gains or inheritance tax, making it a popular destination for the superrich - and their offshore bank accounts.
In 2019, the advocacy group Tax Justice Network ranked Jersey as one of the "worst" tax havens in the world, as reported by the BBC. The government pushed back on the ranking's credibility and said the state is in full compliance with international standards. As of February 2022, the EU does not categorize Jersey as a "non-cooperative jurisdictions for tax purposes."