Bermuda-based Oil Insurance has been downgraded to A- from A by Standard & Poor's (S&P) as a result of its exposure to losses from hurricanes Katrina and Rita.
The ratings remain on under review with negative implications.
S&P credit analyst Mohammed Ashab said: “The company's expected losses from hurricanes Katrina and Rita demonstrated the volatility of its liabilities, which is exacerbated by its relatively aggressive investment strategy.”
Oil recently upped its reserves by $1bn to cover expected losses from the storms.
