Bayer AG (BAYRY) shares fell sharply in Frankfurt Tuesday after a U.S. judge upheld a verdict that found weedkillers sold by its Monsanto franchise caused a California man's terminal cancer, but slashed the damage payout by nearly three quarters.

San Francisco Superior Court Judge Suzanne Bolanos said Bayer would need to pay $39 million in punitive damages and a further $49 billion in compensatory damages to Dewayne Johnson, a groundskeeper who worked for the San Francisco school district, who had argued that Monsanto's 'Roundup' and 'Ranger Pro' weedkillers, as well as its other glyphosate-based products, did not carry sufficient warnings for the risks of cancer that they carried. 

"The court's decision to reduce the punitive damage award by more than $200 million is a step in the right direction, but we continue to believe that the liability verdict and damage awards are not supported by the evidence at trial or the law and plan to file an appeal with the California Court of Appeal," Bayer said in a statement.

Bayer shares were marked 7.8% lower in the opening minutes of trading on the Deutsche Boerse in Frankfurt to change hands at €70.60 each, the lowest since September 13 and a move that extends its year-to-date decline past 32%.

A jury awarded Johnson $289 million in total damages following a controversial verdict reached earlier this summer. Monsanto, which is now a wholly-owed subsidiary of Bayer following last year's $63 billion acquisition, said at the time that the verdict "does not change the fact that more than 800 scientific studies and reviews ... support the fact that glyphosate does not cause cancer, and did not cause Mr. Johnson's cancer".

Johnson, 46, said he contracted non-Hodgkin's lymphoma from his use of the weedkillers, and filed a case against Monstanto in 2016, alleging internal memos suggested the company knew the dangers its products posed but failed to warn customers.

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