Bayer is planning to up its takeover offer for the US-headquartered Monsanto for the fourth time, according to a report on Tuesday on the website of the German newspaper Rheinische Post.

The Leverkusen-based company is reportedly planning to offer $129 (115 euros) a share for the multinational biotechnology company, up from the $127.50 it had proposed last week.

Bayer made its first all-cash offer for Monsanto in May, when it proposed an offer of $122 per share. That offer was rejected by Monsanto for being "incomplete and financially inadequate."

The German pharmaceutical company then upped its offer to $125 per share, which was also rejected in July. Bayer reacted at the time with disappointment, saying the "cash offer is a compelling opportunity and represents immediate and certain value for Monsanto shareholders amid recent weak business performance and Monsanto's reduced mid-term outlook."

Bayer persistent

The report of Bayer's latest bid comes after Monsanto acknowledged receipt of last week's offer, and also said it was considering bids by other companies.

As part of this latest bid, Bayer is also planning to offer $3 billion in compensation if the takeover were to be halted by competition regulators.

A merger of the two companies would make Bayer the world's largest crop science company, though the prospect has alarmed farmers worried about the impact it would have on the market for seeds and pesticides.

In addition, the deal would prove controversial because Monsanto is viewed unfavorably by many in Europe, where GM food products are heavily criticized.

blc/kl (AFP)