Chaucer has announced a pre-tax profit of £15m for the six months to 30 June 2003.
This compared to a loss of £400,000 for the same period in 2002.
Gross written premium increased 31.8% to £201.2m, while the combined ratio stood at 83.3%.
Motor Syndicate 587 is expected to make a profit of between 9% and16% on a capacity of £90m.
Marine Syndicate 1084 is expected to make a profit of 7.5%-15% on a capacity of £82.4m. Non-marine Syndicate 1096 is expected to make a profit of 12.5%-20% on a capacity of £148.4m.
Earlier this year, Chaucer announced plans to merge syndicates 587, 1084 and 1096 for the 2004 year of account. The new merged Syndicate 1084 will have a capacity of £400.2m.