WASHINGTON (TheStreet) -- The Justice Department is investigating whether Standard & Poor's improperly rated dozens of mortgage securities in the years leading up to the financial crisis, The New York Times reported.The investigation into Standard & Poor's, a unit of McGraw-Hill ( MHP), began before the company cut the triple-A credit rating of the U.S. this month, the newspaper said. It cited two people interviewed by the government and another briefed on such interviews. The Justice Department has been asking about instances in which S&P's analysts wanted to award lower ratings on mortgage bonds but may have been overruled by other S.& P. business managers, the Times reported. The Times said it's unclear if the Justice Department investigation involves the other two ratings agencies, Moody's ( MCO) and Fitch, or only S&P. Ed Sweeney, a spokesman for S&P, told the Times in an e-mail: "S&P has received several requests from different government agencies over the last few years. We continue to cooperate with these requests. We do not prevent such agencies from speaking with current or former employees." The Times noted that despite the public scrutiny and outcry over the ratings agencies' failures during the financial crisis, many investors still rely on ratings from the three main agencies for their purchases of sovereign and corporate debt, and other complex financial products. Companies and some countries -- but not the U.S. -- pay the agencies to receive a rating. For decades, the government issued rules that banks, mutual funds and others could rely on a AAA stamp for investing decisions, bolstering the agencies' power. A successful case or settlement against S&P could accelerate the shift away from the traditional ratings system, the Times said. -- Written by Joseph Woelfel >To contact the writer of this article, click here: Joseph Woelfel >To submit a news tip, send an email to: firstname.lastname@example.org.