LONDON (BLOOMBERG) - Russia's billionaires are starting to feel the heat from Western sanctions inflicted after President Vladimir Putin's decision to invade Ukraine.

The country's ultra-rich, who rank among the world's 500 wealthiest people, have now lost a combined US$83 billion (S$113 billion) this year, according to the Bloomberg Billionaires Index.

Stock market declines have been so extreme that Russia's central bank halted local trading on Monday (Feb 28), meaning some of the losses are understated. Shares of London-listed Russian companies, from gas producer Novatek to steelmaker Severstal, crashed by more than 50 per cent on Monday after the United States, the European Union, Britain and other countries ratcheted up sanctions.

On top of the paper losses, penalties are starting to hit closer to home.

Roaming the skies in their Boeing, Gulfstream and Bombardier jets is now trickier after the EU joined Britain on Sunday in banning Russian-owned private planes from its airspace.

Their discreet purchases of high-end London real estate may get more difficult, too, with Britain fast-tracking legislation that would require foreign property owners to disclose their identities, rather than hiding behind holding companies.

Superyachts owned by Russian billionaires are also on the move as the US and its allies prepare further sanctions on their property.

Data reviewed by CNBC shows at least four of these massive yachts sailing towards Montenegro and the Maldives. The Maldives does not have an extradition treaty with the US, the report said.

The EU on Monday adopted sanctions on some of Russia's ultra-wealthy, including metals tycoon Alisher Usmanov, Alfa Group owners Mikhail Fridman and Petr Aven, and steel magnate Alexei Mordashov. The measures also impact Mr Putin's long-time spokesman Dmitry Peskov, state media figures and senior military officials.

Combined with the sanctions already in place in the US and Britain, the latest round of targeted penalties suggests that governments may be viewing Russia's rich elite as another key pressure point as Mr Putin continues his invasion of Ukraine.

Russia's US$1.5 trillion economy is already reeling from sanctions that targeted key banks and may prevent Mr Putin from accessing the bulk of more than US$640 billion in central bank reserves. Those restrictions have roiled the nation's markets and are having a knock-on effect on some of the country's largest fortunes.

Lukoil chairman Vagit Alekperov has seen his net worth tumble by about US$13 billion this year, the biggest drop among the 22 Russian billionaires on Bloomberg's wealth index. The oil company's London-traded shares plunged 62.8 per cent on Monday.

Mr Gennady Timchenko, one of the first oligarchs to be sanctioned by Britain, has lost almost half of his net worth this year, with his fortune plunging US$10.6 billion. Fellow Novatek shareholder Leonid Mikhelson has seen US$10.2 billion erased from his wealth in 2022.

The Ukraine crisis has also sharpened the focus on Mr Roman Abramovich, one of the most high-profile billionaires, with assets including a stake in steelmaker Evraz and Chelsea Football Club.

Mr Abramovich handed control of Chelsea FC to the trustees of the Premier League soccer club's charitable foundation on Saturday. A spokesman said he has also been approached by Ukraine to help broker a peace with Russia.

Aside from the football club, which could be worth more than US$2 billion, many of his other assets are also outside Russia or listed on foreign exchanges. His stake in Evraz is listed in London, as are holdings in energy firms Velocys and AFC Energy, while his position in tech company Yandex is listed in the US.

His real estate holdings range from Israel - where he is a citizen - and France to a mansion near Kensington Palace in London's billionaires row. New York property records show he transferred a mega mansion on the Upper East Side to his former wife in 2018.

Mr Abramovich, 55, who is not currently on Britain's sanctions list, has a net worth of about US$13.9 billion, down by about US$5 billion this year, according to the Bloomberg index.

Follow The Straits Times' live coverage on the Ukraine crisis here.