FRANKFURT (Reuters) - Two law firms are suing Bayer for damages on behalf of shareholders, claiming the German group’s management should have warned of the risk of lawsuits over the Roundup weedkiller when Bayer acquired Roundup maker Monsanto. Weekly Wirtschaftswoche reported on Friday that two law firms, Hausfeld and Tilp, are pressing civil charges with a court in Cologne, Germany, on behalf of investors who were affected by the drop in the share price in the wake of the Roundup litigation and later settlement. Bayer acknowledged in a statement it was being sued and said it would defend itself against what it described as unfounded claims. “Bayer conducted appropriate due diligence regarding the acquisition process. This has also been confirmed by the studies of independent experts,” a Bayer spokesman said in a statement. The German drugs and pesticides maker agreed to acquire seed maker Monsanto in 2016 and its shares plunged in 2018 when it lost court cases in the United States to plaintiffs who alleged that the use of Roundup caused their cancer. An $11 billion outline settlement of those cases in June last year has turned out to be $750 million more expensive amid a struggle to finalise the deal. The shares are down about 45% since Bayer lost the first Roundup court case in August 2018. Wirtschaftswoche said that the court hearings in Germany were not expected to begin before the end of 2021.