WASHINGTON — The three main credit-rating agencies failed to rein in conflicts of interest in giving high ratings to risky securities backed by subprime mortgages, federal regulators said Tuesday.

The results of the year-long review by the Securities and Exchange Commission illuminate the role of Wall Street's credit-rating industry in the turmoil that has gripped the financial markets in recent months.

The three agencies that dominate the industry — Standard & Poor's, Moody's Investors Service and Fitch Ratings — have been widely criticized for failing to identify risks in investments tied to high-risk subprime mortgages.

Among the conflicts of interest cited in the SEC report were the practice of companies that issue the securities paying the rating agencies for their work.

The SEC last month proposed new rules designed to stem conflicts of interest and expand disclosure for credit rating agencies.