NEW YORK (Bloomberg) — Primary insurers and reinsurance companies are "overly optimistic" about the outlook for casualty claims that may arise years into the future, Axis Capital Holdings Ltd. chief executive officer John Charman said.

"I've been extremely concerned about some of the companies in our industry," Charman said yesterday at a conference hosted by Standard & Poor's in Brooklyn, New York. "I still struggle to see how casualty underwriters on the primary side are getting paid adequately" for policies that may generate claims years from now, Charman said.

Charman also said reinsurers are being pushed by their shareholders to consider mergers to boost returns.

He cited investor "frustration" with executives in the industry that aren't seeking deals.

"I don't think you'll find many managers that are keen about combining with someone else," Charman said.

Axis, which provides reinsurance and primary insurance, is based in Bermuda.