Standard & Poor's has lowered its counterparty credit rating on Marsh & McLennan from A+ to BBB+.
S&P said the rating will remain on CreditWatch with negative implications, where it was placed after the New York attorney general announced his investigation into the world's largest insurer.
The suspension of the market service agreements practice at MMC is expected to hit the company's profits, said S&P, therefore its rating has been lowered.
The ratings agency said reduced earnings would diminish MMC's ability to rapidly reduce the short-term debt that was assumed in conjunction with the $1.9bn acquisition of Kroll this summer.
The future problems arising from Spitzer's investigation into placement service agreements are uncertain, said S&P.
S&P credit analyst Steven Ader said keeping the ratings on CreditWatch was a result of “the ongoing uncertainties of the situation, including the potential for further negative developments with respect to the bid-rigging allegations and possible adverse effects such developments might have on Marsh's competitive position, earnings, or cash flow."
S&P added that unless criminal charges were brought against MMC it believed the company would be able to withstand Spitzer's investigations due to the operational profile of the company.
