General Reinsurance Corporation’s history began in 1921 when two Norwegian companies, Norwegian Globe and Norwegian Assurance, merged and took the name General Casualty and Surety Reinsurance Corporation. In 1923, American investors acquired the company and changed the name to General Reinsurance Corporation. In 1929, General Reinsurance affirmed that it would be only a direct reinsurer. In 1954, the company created the first professional casualty facultative reinsurance department. Property facultative followed, beginning in 1956. North America branch offices were opened during this time. In the 1950s, General Reinsurance began writing reinsurance internationally, expanding in this area during the 1960s and 1970s. In 1980, General Re Corporation, the parent holding company, was listed on the New York Stock Exchange.
In 1994, General Reinsurance Corporation formed an alliance with what was then Cologne Re (Kölnische Rückversicherungs-Gesellschaft, which was founded in 1846), now General Reinsurance AG. In 1998, General Re Corporation was acquired by Berkshire Hathaway Inc., and in 2003 General Reinsurance Corporation and Cologne Re began marketing under the brand name of Gen Re. In 2009, General Reinsurance Corporation completed its purchase of Cologne Re,whose name was changed to General Reinsurance AG in 2010. The company continues to market as Gen Re.