The International Underwriting Association of London (IUA) is the focal representative and market organisation for non-Lloyd's international and wholesale insurance and reinsurance companies operating in the London Market. The International Underwriting Association of London (IUA) is the focal representative and market organisation for non-Lloyd's international and wholesale insurance and reinsurance companies operating in the London Market. Membership of the IUA offers London Market companies many important. Associate – open to insurance and reinsurance companies outside of London. The International Underwriting Association (IUA) of London, better known as the IUA, represents companies that trade in the London insurance market outside. At IUA we act as an agent on behalf of Lumley, a business division of IAG New Zealand Limited in respect of all Private and Commercial Motor Vehicle Insurance.