Amlin's income showed a major jump in the first quarter, with gross written premium net of brokerage up by 39% to £425m.
Its Syndicate 2001 has £1.1bn of capacity this year, with Amlin's share totalling £860m.
Amlin said this year's reinsurance was placed without an increase in cost as a proportion of forecast written premiums.
The 2001 year of account is expected to make a small profit, before the 11 September losses are taken into account.
The 2002 year of account has developed a gross incurred loss ratio of 24.7% compared to 45.7%, excluding 11 September losses, for 2001 at the same stage.
Lloyd's-based operations Chaucer and Wellington both confirmed previous forecasts for the 2001 and 2002 years of account.