By most accounts 2012 was a great year for McGraw-Hill. It sold its education business for $2.5 billion. It teamed up in a new venture putting together the Dow Jones Industrial Average and the S&P 500 stock indices under the same ownership. And its stock price climbed to five year highs. Then in the past week the federal government sued McGraw-Hill. The lawsuit essentially claims the company defrauded taxpayer-backed mortgage companies by giving IOUs backed by trashy home mortgages a triple A rating. The Department of Justice has threatened to ask for $5 billion. That’s almost half the company’s public value.

On Tuesday, when McGraw-Hill reports its fourth quarter and full year 2012 results, no one will be impressed. The company had hoped to trumpet its restructuring last year, separating mature businesses like school textbook publishing from the faster growing and more appealing financial services businesses. It is a strategy that had worked. With interest rates at historic lows, companies have been rushing to issue bonds. In the third quarter, the volume of new corporate IOUs from U.S. companies jumped 72 percent from a year earlier. European companies selling bonds more than doubled. In order to sell those bonds to investors each needs a blessing from a credit ratings agency like McGraw-Hill’s Standard and Poor’s unit. This business brings in about three-quarter’s of the profits for McGraw-Hill.

But more than four years after the housing bust began, McGraw-Hill’s credit rating business is in the cross hairs of government prosecutors. Its reputation has been hurt and stock has plunged 25 percent. How the company will survive 2013 is what investors want to hear Tuesday.

Tom Hudson is anchor and managing editor of Nightly Business Report, produced by NBR Worldwide and distributed nationally by American Public Television.