The International Organisation of Securities Commissions, the umbrella body for the world's securities regulators, may demand that credit ratings agencies' involvement in the creation of complex debt securities they also rate is curbed as one of the chief changes to their business in the wake of the credit crisis.

IOSCO said in a statement yesterday that ratings agencies may be forced to adopt a new code of conduct that includes: prohibition of advice on the design of structured products which an agency also rates; "reasonable steps" to ensure "a credible rating" and disclosure of the assumptions underlying the individual ratings on structured finance transactions.