Fitch ratings has downgraded the financial strength rating of Royal & SunAlliance USA insurance subsidiaries to BB- from BBB+.
The company has been put on a negative ratings watch, the agency said.
The downgrade indicates Fitch's concerns about the level of capitalisation at RSA USA following the company's rights issue and selling of renewal rights for some of its US business.
R&SA could also suffer increases in reinsurance collectability risks due to the planned run-off of the significant amount of business, the ratings agency said.