The ratings firm said it believes Willis Group now maintains more stable debt levels and improved leverage and coverage metrics than it had seen in 2008.
"We believe management will continue to proactively manage its financial profile with tighter control over cash flows and capital expenditure including discretionary spending," S&P said. The credit rater also noted the company's strong operating performance and a good competitive position.
Looking ahead, S&P said it expects low-single-digit organic growth in this year and next, saying it believes Willis Group can offset weak economic conditions and lower rates through its international expansion efforts and strong sales strategy.
The firm said it could raise the company's rating by one notch within the next 12 to 24 months if Willis' financial profile continues to improve.
S&P affirmed Willis Group's BBB- rating, which is the last rung of investment grade territory.
One of the world's largest insurance brokers, Willis Group has been generating new business and reporting organic growth in commissions and fees, though its results have been hindered by declining premium rates. Last month, the company reported its second-quarter earnings slipped 4.5% amid higher costs and charges.