Brit Insurance, the Lloyd's insurer and reinsurer, has launched a £204m cash call to enable it to operate more business.
The extra capital will enable it to support £1bn of premium income for 2003. Brit said it would use the capital to underwrite more business.
The move follows a similar announcement earlier this month from Hiscox, which raised £110.5m to support growth in new business.
The move comes a year after Brit initially turned to the market to raise £154m, but since then insurance premiums have continued rising. Marine, aviation and transport premiums have been rising by up to 40 per cent, it said.
Chief executive Neil Eckert said: "This fundraising will represent a significant step for our company.
"With the added strength to our balance sheet, our underwriting teams should be well placed to take advantage of the very strong market conditions which we are experiencing."
Brit will raise £204.2m through the placing and open offer of 319 million new shares.
Brit reported first-half operating profits of £3m against £7.8m last time. Pre-tax losses were £3.7m up £1.3m from last year.