Simultaneous second mortgages are becoming an increasingly important part of the subprime mortgage market. But a new investment bank report suggests that spotty disclosure practices by issuers have made the so-called piggyback loans a potentially risky bet for investors. “Given the important implications of piggyback performance, we believe investors should ask for information on piggybacks on all deals and employ the ‘trust but verify’ concept when looking at deals where no piggyback seconds are reported,…