"New originations will be down, and nonprime borrowers will start to re-emerge," said Tim Martin of TransUnion, which reported a 23 percent drop in borrowers' making late payments in the third quarter versus a year earlier.
Since the recession began in 2008, the percentage of nonprime borrowers—or those with a Vantage Score lower than 700, according to Martin—has fallen from 12 percent of all originations to below 6 percent. That share is ticking up slightly.
"The origination volumes are starting to lower, so [banks say] let's start easing up a little bit, take a little bit more risk and help some folks get some mortgages done," Martin said.
(Read more: Strong jobs report is downer for housing)
After tightening in August and September, credit eased slightly in October, according to a monthly report from the Mortgage Bankers Association.
"Some investors reduced minimum credit scores on certain products," the report said. "At the same time, other investors reduced the availability of cash-out refinances and limited other programs to primary residences in programs which previously allowed for second and investor homes. The net impact was a slight increase in the index for the month."
That slight easing may again be just for the most creditworthy borrowers. Options for those with smaller down payments and lower scores are still limited.
D.R. Horton, the nation's largest home builder, said the share of buyers using low-down-payment loans from the Federal Housing Administration is dropping, as the agency has raised its insurance premiums.
The entry-level builder, which reported fiscal fourth-quarter earnings Tuesday, said the share of first-time buyers dropped to 43 percent from 53 percent year over year. The average FICO score for a D.R. Horton buyer is 723—high by historical standards.