Alisher Usmanov is no longer Russia's wealthiest individual after losing $4.5 billion of his fortune last year, according to Wealth-X.

The founder of conglomerate USM Holdings and co-owner of English football club Arsenal saw his wealth shrink 25 percent from the onset of the Ukraine conflict in March to December, leaving his current net worth at just under $14 billion, compared with $18.3 billion in early 2014.

Viktor Vekselberg, co-founder of the Renova conglomerate, now tops the country's rich list with a net worth of $14.7 billion. The Ukrainian-born businessman, ranked 63rd on Forbes' global billionaire list in 2014, lost only $200 million during the March-December period.

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Meanwhile, oligarch Mikhail Fridman lost $2.7 billion, or 18 percent, of his wealth. Fridman is a leading shareholder of Alfa Group, one of Russia's largest financial-industrial consortiums.

The trio is among the five richest Russians on Wealth-X's list. Their wealth shrank amid a triple whammy of crashing oil prices, extreme currency devaluation and rising interest rates.

Brent crude's more than 50 percent tumble over the past six months saw November gross domestic product in Russia, the world's second largest oil exporter, contract for the first time in five years. Meanwhile, the ruble lost over half of its value in 2014.