Cosmo Energy, Japan’s third-largest oil refiner, could find it difficult to gather shareholder support to block a hostile takeover bid from activist investors, Cosmo’s CEO Shigeru Yamada told Reuters in an interview published on Friday. Cosmo Energy has been fighting an activist investor group led by Yoshiaki Murakami for a year now and has voted on a “poison pill” tactic to dilute the stake of the activist investors if their group buys more shares without complying with all the procedures or without stating the…