WASHINGTON — Top executives at two credit rating agencies defended themselves Friday against charges that, to retain market share, they knowingly issued inflated ratings on mortgage-backed securities before the financial crisis and put off making needed changes in their standards.

Officials from Moody's Investors Service and Standard and Poor's Inc. tried to rebut a congressional report released Thursday by arguing that they had been public about flaws in the mortgage market and had made changes to better adjust to risk.

Subscribe Now

Access to authoritative analysis and perspective and our data-driven report series.

14-Day Free Trial

No credit card required. Complete access to articles, breaking news and industry data.