The ongoing debate over the need for a government guarantee to sustain the benefits of the to-be-announced MBS market moved this week to the Senate Housing, Banking and Urban Development Committee, where researchers covered both sides of the issue for a group of lawmakers who aren’t likely to act on their counsel any time soon. “Proponents of privatization ignore that the jumbo market does benefit from a government guarantee indirectly in multiple ways,” said Adam Levitin, professor of law at Georgetown University. “The jumbo market has long aped the standards set by the [government-sponsored enterprises] in the conforming market, including...