Climate activists have been shining a spotlight on the financial industry's support for industries such as coal that accelerate climate change.

Hannover Re, like many other insurers, has said that it is reducing its exposure to coal-based risks.

So-called treaty reinsurance contracts involve reinsuring an insurer's entire portfolio, and it can be tricky to check for coal exposures.

Silke Sehm, in an interview at the Reuters Future of Insurance Europe conference, said talks with customers on treaty contracts have begun "to support our clients in the transition phase".

"We have to listen to the client, depending on where they are," she said.

(Reporting by Carolyn Cohn and Tom Sims; Editing by Maria Sheahan)