U.S.-based Monsanto Co (MON.N) sweetened its offer to buy Switzerland’s Syngenta AG (SYNN.VX), valuing the company at around $47 billion as it tries to lure the Swiss firm to the negotiating table, a person familiar with the matter said on Monday. Monsanto, which wants to combine its world-leading seeds business with Syngenta’s own seeds and pesticides, raised its offer to 470 Swiss francs ($501.98) per share from CHF 449 per share, the person said. The increased offer, which sent Syngenta’s shares jumping, is aimed at ending the stalemate between the two firms.