The agrochemical company is set to reject a $62 billion takeover offer from the German pharmaceutical giant Bayer, according to Reuters.
Bayer announced the unsolicited offer on Monday.
The $122-a-share offer was a 37% premium to Monsanto's share price before news broke of Bayer's interest.
Bayer CEO Werner Baumann on Monday said, "We fully expect a positive answer of the Monsanto board of directors."
Monsanto has not publicly commented on the takeover offer since Bayer named its price. It did acknowledge the receipt of a takeover offer last week in response to media reports that an offer existed.
Morgan Stanley and the boutique bank Ducera are advising Monsanto, while Credit Suisse, Bank of America, and Rothschild are advising Bayer.
BREAKING: Monsanto to reject Bayer's $122-per-share bid, seeks higher price