"Renova is now a minority shareholder, holding 48.83 percent of the shares in Sulzer," the Swiss company, which specialises in industrial pumping systems, said in a statement.
"Sulzer confirms that it is no longer a blocked party or subject to sanctions under US law," it said, adding that it was "free from US sanctions".
Sulzer moved swiftly to undercut Renova's control after the United States slapped sanctions on Russian magnate Viktor Vekselberg and his firm, as part of a drive by Washington to target businesses and oligarchs with close links to President Vladimir Putin.
Following the sanctions announcement, Sulzer said its bank accounts in the United States had been partially frozen.
But it explained that the decision to freeze its accounts had been the banks', rather than the US government's.
On Monday, Sulzer said it was buying back five million of its shares from Renova to guard against "disruptions".
"This share transfer has been completed," it said on Thursday.
"The business activities of Sulzer have been considerably disrupted, but the company does not believe that its long-term performance will be affected," it added.
Sulzer saw its share price dive nearly 16 percent on Monday and another 8.5 percent on Wednesday.
Then on Thursday, its shares soared back by 11.8 percent, signalling a return of investor confidence.
The buyback brought "great relief" to Sulzer, Baader Helvea analyst Reto Amstalden said in a market commentary.
Washington unveiled the sanctions targeting Putin's inner circle last Friday.
President Donald Trump's administration has said the measures were aimed at punishing Russia for a range of actions, including election interference and support of the Syrian government.
The measures targeted seven oligarchs, 12 companies they own or control, 17 senior Russian officials and the state-owned arms export company Rosoboronexport.