Moscow/London/Princeton — It was a painful day to be a Russian billionaire.

The combined net worth of the country’s wealthiest people fell by $16bn on Monday — erasing all their year-to-year gains — following last week’s US-imposed sanctions.

All but one of the 27 Russian tycoons listed on the Bloomberg Billionaires Index lost money, led by Siberian nickel miner Vladimir Potanin, whose fortune declined $2.25bn. Lukoil CEO Vagit Alekperov saw his wealth tumble $1.37bn, while Viktor Vekselberg of Renova Group lost $1.28bn.

Vekselberg is one of seven Russian tycoons sanctioned last week by the Trump administration in retaliation for Moscow meddling in the 2016 US presidential election. He took steps on Monday to limit the exposure of his Swiss holdings to the sanctions.

Oleg Deripaska, who was also among those sanctioned, lost $905m on Monday and has seen his fortune dwindle by more than $2bn over the past two trading days. His losses stemmed from his industrial conglomerate En+ Group, whose shares have plunged 54% since Thursday, according to London Stock Exchange data. Through EN+, Deripaska owns half of Rusal, the giant aluminium producer that was also slapped with sanctions.

The MOEX Russia Index of stocks climbed 1.4% by midday, after falling 8.3% on Monday, the most in four years. The rouble weakened 3.2% to 62.67 against the dollar, extending its slump this week to 7.2%.