Most analysts are confident that private mortgage insurance companies will not see their ratings downgraded due to increased competition from the FHA as well as new capital requirements for private MIs proposed by the Federal Housing Finance Agency. But Zacks Investment Research, a research firm that ranks and rates investment products for investors, went against the grain and downgraded MGIC Investment Corp. by two notches due exactly to those reasons. While private MIs have been gaining market share in the last couple of years, Mortgage Guaranty Insurance Corp. and its business competitors will find...