Another bidder is in the running to acquire US reinsurer Transatlantic Holdings.The company announced yesterday that it had reached a confidentiality agreement and was in discussions with a third party.This is in addition to Bermuda-based reinsurer Validus Holdings, which tabled a bid of $47.71 per share for Transatlantic last month.The news is the latest twist in a saga which has already seen a proposed merger with Allied Assurance Company fall through and a $3.25 billion bid from Warren Buffett’s Berkshire Hathaway rejected.