RFC Officials Optimistic as Primary Mortgage Market Heads Toward Sharp Downturn Many mortgage industry forecasters are predicting a huge downturn in new loan production over the next year, as the historic rush to refinance fades to more normal levels, and securitization volume is likely to shrink significantly. But officials at GMAC Residential Funding Corp., the second largest conduit issuer of non-agency MBS in 2003, are optimistic about their firm’s prospects in what could be a