Largest reinsurers worldwide 2024 by gross premiums written

 As of 2024, the third leading reinsurer globally by gross reinsurance premiums written was Hannover Re, with 35.53 billion U.S. dollars. Swiss Re ranked second with almost 40 billion U.S. dollars. Munich Re held the top spot, with written gross premiums exceeding 50 billion U.S. dollars.

Reinsurance involves insurers transferring parts of risk portfolios to other parties in order to spread the risk of having to pay out a large sum in the event of an insurance claim. This encourages insurance companies to assume risk, even when the potential payout will be extremely high, like in the case of a natural disaster. It reduces the risk of insurance companies going bankrupt trying to cover claims.

Reinsurance is an important tool for insurance companies, especially in the case of events which cause large-scale property damage and casualties, such as earthquakes, flash flooding etc. In 2016, the total cost to the insurance industry of weather-related natural catastrophes worldwide was 36.9 billion U.S. dollars. The estimated cost of the 2011 earthquake in Japan to Munich Re was 1.5 billion Euros.

Flooding is becoming more prevalent as global warming increases, so the reinsurance industry will continue be very important in the future. The June 2013 floods in Central Europe caused almost three billion U.S. dollars worth of insured damage. Hurricane Katrina resulted in major flooding in the southern states of the United States in August 2005, which cost 16.3 billion U.S. dollars in insured losses.