Bayer shares drop on move for Monsanto

Deal could be the biggest world takeover this year

Monsanto takeover could cost Bayer 65 billion Pic Getty

German chemicals giant Bayer has made an unsolicited takeover offer for US seeds producer Monsanto. In a statement, Monsanto said it was reviewing the offer, but did not disclose the terms of the offer.

Bayer confirmed the bid, saying a combination would bolster its position as a "global innovation-driven life science company".

Shares in the German company dropped sharply, however, amid concern that a large purchase would affect its credit rating and force ...