Tighter controls on mortgage lending take effect this year, and the prospect has stoked fears of a drastic reduction in credit as banks adjust to the new reality. While some estimates predict the Consumer Financial Protection Bureau's new "qualified mortgage" (QM) rule ultimately could wipe out half of the home-loan market, this doomsday outlook is unlikely in the short term. Although it is still too early to tell, some observers say underwriting could actually loosen under QM. Clarity surrounding the new guidelines -- which ban many risky mortgage products and require lenders to ascertain borrowers' ability to repay -- could encourage lenders to assume more risk and relax their standards, they suggest. Moreover, credit criteria is already so tight that the market may not react much to the new rules. Sterne Agee analyst Jay McCanless notes that mortgage underwriters have been adhering to standards that are even tighter than those required by the CFPB. "As of November," he explains, "the average debt-to-income ratio for completed conforming mortgages was 41 percent versus the 43 percent mandated by" QM. Analysts also say the replacement of Federal Housing Finance Agency acting director Edward DeMarco with Rep. Mel Watt (D-N.C.) could have a positive impact on credit availability, as Watt is likely to kill DeMarco proposals that would have hiked fees and reduced the size of conforming loans, among others.