Call it the mortgage-meltdown creep.

Countrywide Financial Corp. helped trigger a Wall Street sell-off Tuesday when it said that a growing number of customers once considered to be good credit risks were having trouble making their mortgage payments, the Los Angeles Times reports.

Until recently, such problems had been almost exclusively limited to the so-called sub-prime market, for borrowers with flawed credit records and high-cost mortgages.

But Countrywide, the nation’s biggest home loan company, reported Tuesday that it was seeing more of its good-credit “prime” borrowers do the same.

“The spillover into prime, I don’t think, is something that should shock anybody,” Angelo Mozilo, Countrywide’s chief executive, said in a three-hour conference call with investors and analysts to report second-quarter earnings.

The Calabasas-based company said payments were at least 30 days late at the end of the second quarter on 3.4% of prime first mortgages, up from 2.1% a year earlier.

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