The United States imposed major sanctions on Friday against Russian businessmen, companies and government officials, striking at allies of President Vladimir Putin in one of Washington's most aggressive moves to punish Moscow for its alleged meddling in the 2016 U.S. election and other "malign activity.”

Russia’s 50 richest businessmen have reportedly lost close to $12 billion in the days after the United States imposed a new wave of sanctions against individuals and companies close to the Kremlin.

According to the Forbes magazine’s real-time ranking, metals tycoon Vladimir Potanin was the biggest total-value loser with $1.5 billion wiped out. Potanin, part-owner of Norilsk Nickel, was not targeted by the U.S. Treasury Department in its latest wave of sanctions.

Fellow steel tycoon Oleg Deripaska, who has stakes in eight of the 15 entities hit with sanctions, followed with an estimated $1.3 billion erased from his $6.7 billion net worth. Deripaska led the list of Russians to have lost after the sanctions in percentage terms, having almost a quarter of his fortune decimated in a day.

Sanctions-hit member of Russia’s Federation Council Suleiman Kerimov rounded out the top-three with estimated losses of $1.2 billion. Russia’s ninth-richest businessman Viktor Vekselberg, also on the U.S. sanctions list, lost just under $1 billion.

The RBC business portal estimates that the 50 richest Russians lost close to $12 billion on Monday.

Seven sanctioned Russian oligarchs on the U.S. sanctions list lost an estimated $3.3 billion on Monday and posted a cumulative net worth of $32.5 billion, the Vedomosti business daily reported.

Reuters contributed reporting to this article.