FRANKFURT, March 11 (Reuters) - Austrian investment group B&C Industrieholding GmbH said it will make a mandatory takeover offer of 23.40 euros to shareholders in aluminium group AMAG .
B&C on Monday said it made the takeover offer after agreeing to raise its AMAG stake to 46.13 percent of the voting rights, from 29.99 percent at present.
Shareholders that agree to tender will be entitled to a dividend of 0.60 euros in April, B&C said.
In the medium term, B&C plans to raise its AMAG stake to a majority, the company said. B&C said it has secured the right to buy a further 22.6 percent AMAG stake.
In January B&C said it had struck a deal with Oberbank to pool its shareholding in AMAG.
A holding above 30 percent requires a bid to be made to other shareholders under Austrian takeover rules. (Reporting By Edward Taylor; Editing by David Cowell)