Brazilian pulp and paper company Suzano has been in talks with its advisers about sweetening its $15 billion acquisition offer for International Paper (IP), people familiar with the matter said on Monday. Earlier this month Suzano had approached IP to verbally express interest in an all-cash acquisition that was worth roughly $42 per share. Such a deal is conditional on IP abandoning its agreement to acquire British packaging firm DS Smith for $7.2 billion. IP rejected Suzano’s initial approach, and Suzano is discussing raising its offer by a few dollars per share, one of the sources said. The sources cautioned there is no certainty that a new bid from Suzano would succeed.IP’s shares jumped more than 1.3% during market hours on the news on Monday, and further extended gains in trading after the bell. Shares of Suzano, which has a market value of 67.1 billion reais ($13.15 billion), closed up more than 1% in Brazil.