* Rival shareholders fight over Swiss steelmaker's future
* Vekselberg vehicle accuses Swiss billionaire of sowing panic
* Shareholders meet on Dec. 2 for capital increase vote
By John Miller
ZURICH, Dec 1 (Reuters) - The fight for control of Schmolz+Bickenbach flared on Sunday, with Russian oligarch Viktor Vekselberg's investment vehicle accusing a rival shareholder of trying to increase its stake on the cheap via a planned share issue.
Schmolz+Bickenbach shareholders are due on Monday to decide on a proposed issue of up to 614.25 million Swiss francs ($616 million) worth of shares, through which Swiss billionaire Martin Haefner aims to raise his 17.5% stake to 37.5%.
The capital increase would be three times Schmolz's market capitalisation and follows a previous rescue of the company just six years ago.
Haefner contends failure of this latest capital increase would likely lead to bankruptcy, as the 100-year-old steelmaker faces a slump in demand from the German car industry.
But Vekselberg's investment firm Liwet Holding, which owns nearly 27% of Schmolz+Bickenbach, said in a letter received by media outlets that Haefner aims to become the dominant shareholder at a discount by sowing panic over the company's future.
"The more dramatically you describe the situation of Schmolz+Bickenbach, the more favourable the takeover of control will be, diluting and devastating other shareholders," Liwet said in its letter addressed to Haefner.
Haefner's Swiss investment company, BigPoint Holding AG, did not immediately return a message seeking comment. Schmolz+Bickenbach could not immediately be reached via email or phone on Sunday.
A representative of the Schmolz+Bickenbach founding family in Germany that still owns about 10% of the shares and which has allied with Vekselberg in past campaigns also could not be reached for comment.
Swiss newspaper SonntagsZeitung reported on Sunday that the factions were in talks over a possible solution, citing people close to Haefner.
In its letter, Liwet pledged to contribute "as much money as necessary for the company to survive," provided the plan avoids a change in control, and called for a review of "hidden reserves," possible shareholder loans and disposal of non-core assets to help keep Schmolz+Bickenbach afloat.
"Unfortunately, Liwet has so far not received a transparent explanation ... as to how large the liquidity requirement really is," it said.
Vekselberg took his stake in Schmolz+Bickenbach in 2013, during a previous crisis in which he allied with the founding German family ahead of a 438 million franc capital injection.
Vekselberg owns 40% of Liwet, though his ability to influence its Swiss holdings has been limited after he was placed in 2018 under U.S. sanctions targeting Russian President Vladimir Putin's inner circle following alleged Russian meddling in 2016 U.S. elections. [reut.rs/2rEowhR ] (Reporting by John Miller; Editing by Mark Potter)