A Swiss court has awarded £2.6bn in a record-breaking divorce settlement to the former wife of the Russian oligarch who owns AS Monaco football club.

The ruling, dated 13 May but not made public until Monday, deprives billionaire Dmitry Rybolovlev of 4bn Swiss francs – half of his immense fortune – in what Elena Rybolovlev's lawyer called "the most expensive divorce in history".

Marc Bonnant said he believed the settlement set an all-time record. "Compared to cases like [the London-based oligarch Boris] Berezovsky, the advantage is that it's an official judgment, not something sneaky behind the scenes."

The ex-wife of Berezovsky, Galina Besharova, notched up Britain's costliest divorce in 2011 when he agreed to pay her £220m. But details remained secret in that "amicable settlement".

Rybolovlev's lawyer, Tetiana Bersheda, announced on Monday evening that the oligarch would appeal against the judgment.

Bersheda said the ruling had confirmed "both the validity of the trusts and the validity of the asset transfer to them that occurred long before his wife initiated divorce proceedings". She suggested that Rybolovlev felt confident about appealing on the ground that the trust structures were "immune from legal challenge", raising a question over whether the oligarch's properties outside Switzerland would be vulnerable to the ruling.

The couple met when they were students in Perm in the Ural mountains, and married 23 years ago in Cyprus. But they had been fighting for six years over a divorce settlement. Bonnant said Ms Rybolovlev had obtained "exactly" the sum she had sought from the court in Geneva where she lives. She was also awarded custody of their younger daughter, Anna, who is 13.

Asked why it had taken six years to obtain a judgment, the lawyer replied: "Because the oligarch put up strong resistance." Bonnant said the harsh ruling took into account the fact that Rybolovlev, who, according to Forbes is worth $8.8bn and is the world's 147th richest man, had attempted to conceal the full extent of his assets via offshore ventures.

Like other Russian oligarchs, Rybolovlev, 47, built his fortune on the back of former Soviet industries, although he studied for a medical career and had trained to be a cardiologist. He concentrated on developing the potash company Uralkali and transformed it into one of the world's biggest fertiliser producers – despite spending 11 months in jail in 1996-97 while awaiting trial on a charge of ordering a contract killing. After being acquitted, he sold his controlling share of 53% in Uralkali for a reported $6.5bn.

In 2010, he purchased a 9.7% stake in the Bank of Cyprus, the island's biggest bank, before buying the Ligue 1 Monaco club which was taken out of royal ownership for the first time. Thanks to his seemingly bottomless pockets, the club spent £146m on summer signings last year. The oligarch lives in a $300m penthouse in the city state.

But there has been speculation that Rybolovlev's acquisitions through a third party since 2008, when his marriage fell apart, may have been an attempt to keep his fortune away from his wife. His spokesman has said that even his 66% stake in the Monaco Football Club was bought by a trust in his daughter Ekaterina's name, not by the billionaire personally.

In April last year, a trust acting for Ekaterina, 24, purchased Skorpios, the private island of Athina Onassis Roussel, the Onassis shipping empire heiress. Greek media reported that the island was sold for about $150m. Elena Rybolovlev persuaded the Geneva authorities to order a freeze on her husband's assets worldwide, but did not manage to apply it to trusts in their daughters' names.

Rybolovlev's property empire extends to America, where he bought Donald Trump's Palm Beach mansion, La Maison de l'Amitié in Florida in 2008. He bought a New York apartment for $88m again using the trust in his daughter Ekaterina's name.

Under the historic divorce settlement the oligarch is to give his ex-wife half of the property deeds to their two former homes in Coligny, a fashionable district in Geneva. It also orders him to hand over hugely valuable items of antique furniture and jewellery.

Bonnant said the judge's ruling sent a message that "recourse to offshore structures, such as Cypriot trusts, to hide assets from creditors, has no effect" .He said he was confident the court decision would be upheld if Rybolovlev were to appeal. The verdict, Bonnant said, fell "like a hammer blow" on the Russian tycoon.

A representative of AS Monaco was not available for comment.

• This article was amended on 20 May 2014 to include comments from Rybolovlev's lawyer, Tetiana Bersheda.