Atrium Underwriting plc (Atrium) is a leading specialist insurer at Lloyd's of London. Atrium's expertise is in managing and underwriting specialist insurance and reinsurance business exclusively at Lloyd's.

Atrium combines one of the highest quality managing agencies at Lloyd's with one of the best performing owned underwriting portfolios at Lloyd's.

Atrium manages two leading Lloyd's syndicates, 570 (non-marine) and 609 (marine), both with track records of profitability well ahead of the Lloyd's average.

Atrium owns an underwriting portfolio with participations on 7 selected Lloyd's syndicates (including 570 and 609) giving approximately £158m of underwriting capacity for the 2005 year of account.