Mortgage-bond issuers and investors moved to quell questions about whether banks properly assigned loans made during the securitization boom, arguing that such transfers are valid even if the loan’s owner isn’t identified in certain records. The American Securitization Forum, a trade group for the securitization industry, is set to release on Tuesday a 28-page defense of widely used practices for bundling mortgages into securities. The securitization process and foreclosure-documentation practices are likely to face criticism from lawmakers at a Senate Banking Committee hearing Tuesday. A separate report from the Congressional Oversight Panel, also being released Tuesday, raises questions about whether improper document transfers could create additional liabilities for the biggest U.S. banks. The consequences could be “severe,” the report said, “if documentation problems prove to be pervasive and, more importantly, throw into doubt the ownership of not only foreclosed properties but also pooled mortgages.”