A worker molds steel at Swiss Steel AG's factory near Lucerne, Switzerland in October 2008. The company is partly owned by Swiss steel industry giant Schmolz + Bickenbach. Reuters / Michael Buholzer

Russian steel tycoon Viktor Vekselberg has acquired a 20.46 percent stake in Swiss steelmaker Schmolz+Bickenbach (STLN:SW), the company's chair announced Sunday.

The move, which was made during a Friday shareholder meeting, forced the chairman of the indebted company to announce his resignation and ends a long-running power struggle between the board of directors and the company's founders' descendants, who have been battling over restructuring for months.

"There will be a new general meeting and a new board of directors with (Vekselberg's) Renova as dominating shareholder," Schmolz+Bickenbach's chairman Hans-Rudolf Zehnder said in a statement published in Swiss newspaper Schweiz am Sonntag on Sunday. "I will be gone then."

Renova and Schmolz+Bickenbach GmbH & Co KG (S+B KG) now own 40.46 percent of Schmolz+Bickenbach combined, which under Swiss law forces Vekselberg to offer to buy the remaining shares.

Following decisions taken at Friday's shareholder meeting, S+B KG said Saturday that Lucerne, Switzerland's commercial registry office had granted its request to block new entries to the steelmaker's share register. This includes a 330 million Swiss rights issue, worth $348.8 million, approved by shareholders on Friday that was to be executed by the board of directors and re-elected chairman Zehnder, according to Reuters.

Ahead of the shareholder meeting, another major shareholder in Schmolz+Bickenbach, board member Gerold Buettiker's Gebuka, obtained a court order to allow S+B KG to vote with only 20.46 percent of its shares instead of the 40.46 percent it owned, because the remaining 20 percent are tied into a shareholders' agreement with Gebuka.

S+B KG said because it could only vote with about half of its shares, it had a decisive influence on the outcome of the shareholders' votes on Friday. Renova said it did not want to increase its stake further and hoped existing shareholders would keep their shares.