In a statement on Wednesday, Bayer said that it would pay between $8.8 billion to $9.6 billion to resolve current litigation against Roundup, and an additional $1.25 billion to support a separate class agreement in case the company needs to address future litigation.
Leverkusen, Germany-based Bayer's American depositary receipts climbed on the settlement news, gaining as much as as 5%.
Bayer stressed that the agreement would not cover three cases now going through the appeals process.
The Roundup deal would bring closure to around 75 percent of current litigation that involves roughly 125,000 filed and unfiled claims, the statement said.
Potential future cases will be governed by a class agreement that is subject to court approval. "At the same time, the extensive body of science indicates that Roundup does not cause cancer, and therefore, is not responsible for the illnesses alleged in this litigation".
"Sadly, we have had situations in the past where litigation has resolved in the United States and then Australian victims have been made to wait years, and millions of dollars, sometimes tens of millions of dollars, has been expended in legal fees before a resolution can be reached", Mr Watson said. No lawsuits are required for the payouts, but farmers must show proof of crop damage or reduced yields tied to dicamba contamination, the company said.
The company said it expects contributions from co-defendant BASF toward the dicamba settlement. The settlement also resolves many other cases over the herbicide dicamba as well as water contaminated with toxic chemicals called PCBs.
Bayer has repeatedly said Roundup is safe and important to farmers who use the herbicide in combination with the company's genetically modified seeds.
Bayer said the Bader case was not included in the proposed settlement. A federal judge ruled earlier this week that California officials can't force companies to place warning labels on glyphosate-based products.
It would also settle about 95 percent of the cases now set for trial and establish "key values and parameters" to resolve the remainder of the claims, Bayer added.
Glyphosate is relatively affordable and the most commonly used agricultural herbicide in the United States, according to the U.S. Environmental Protection Agency.
Bayer faced a surge in new lawsuits previous year after it lost the US jury trials, and investors issued a rare rebuke to Baumann last spring.
Still, given the Roundup settlement's hefty price-tag, investors may continue to question whether the Monsanto takeover will ever be worth what Bayer paid, Markus Mayer, an analyst at Baader Bank, said via email.
"I can see how it's attractive for Bayer", he said.
The U.S. Environmental Protection Agency (EPA) said in January that a regulatory review of glyphosate, the main ingredient in Roundup, is not a carcinogen.