A Belgian court has lifted a freeze on Kazakh National Fund assets worth $21.5bn imposed as part of a dispute with Moldovan oligarch Anatolie Stati, the Kazakh justice ministry said on May 30.

It is unclear whether $21.5bn is the full amount placed under the freeze last year. Previous reports referred to $22.6bn, or approximately 40% of the fund’s assets. The Kazakh government said on May 25 it was asking an appeals court to reverse the decision that required the Bank of NY Mellon to freeze the estimated sum of $22bn. Kazakhstan’s sovereign wealth funds are invested mostly in bonds.

Under a 2013 decision by the Energy Charter Treaty (ECT) tribunal, Kazakhstan is required to pay $500mn to Stati’s company Ascom for an unlawful oil and gas fields and liquefied petroleum gas (LPG) industry nationalisation. Ascom successfully took steps to enforce the ruling in Swedish and Dutch jurisdictions, where assets of the Kazakh state have been appropriated. That success led to the freeze order. Kazakhstan has sought to reverse the ECT’s ruling in the UK and the US to no avail. The US District Court for the District of Columbia ruled in March in favour of Stati, granting enforcement of $520mn.

BNY Mellon says the Belgian and Dutch court orders require it to freeze the assets, while Kazakhstan’s lawyers say that deposits held at an English branch of an international bank should be subject to UK courts, and, as such, the English branch should not recognise the foreign orders.

Stati along with his Ascom Group, his son Gabriel Stati and Terra Raf Trans Trading said in a statement in February that they retained the full benefit of an attachment of Kazakhstan’s property, including cash, bonds and equity shareholdings.

The High Court of Justice in London recently ruled that the dispute between the Central Asian nation and the Moldovan businessman must proceed to trial in October.