The architects of the ambitious bipartisan housing-finance reform bill in the Senate have put considerable emphasis on preserving access to the new secondary-mortgage market for smaller lenders. They may not have it right yet. According to Fannie Mae and Freddie Mac, the so-called small lender mutual envisioned by Sens. Tim Johnson, D-SD, and Mike Crapo, R-ID, would face significant challenges in a new mortgage-finance world where large institutions could vertically integrate ...