Brokers and Reinsurance Markets Association
A forum for treaty reinsurance professionals.
http://www.brma.org/

Intermediaries and Reinsurance Underwriters Association (IRU)
Organization of reinsurance intermediaries and companies engaged in the assumption or placement of property/casualty treaty reinsurance.
http://www.irua.com/

Reinsurance Association of America
Non-profit trade association of US property and casualty reinsurers and reinsurance brokers.
http://www.reinsurance.org

The Reinsurance Research Council (RRC)
An organization representing professional property/casualty reinsurers registered in Canada.
http://www.rrccanada.org

Under 35s Reinsurance Group
Group engaged in educational and social activities for young professionals in the reinsurance market.
http://www.under35s.com/