It will take some time for rating agencies to re-establish their credibility. Second, investors have discovered that there are considerable costs of accumulating independent information on non-standardized products in order to perform, at a minimum, risk-based analysis to check the opinions of credit-rating agencies. This is a case where markets themselves should be able to establish standards to minimize information costs.
In the interim, the central bank or a regulatory body may help to reduce the costs of information. The Bank of Canada has adopted high disclosure standards for ABCP that it will accept as collateral in its Standing Liquidity Facility. This may encourage market participants to raise their own standards. Whether they do in the end will be their decision.