The New York Fed warns that surging delinquency rates for subprime auto loans are a "significant concern" about the actual health of the car industry.

"The worsening in the delinquency rate of subprime auto loans is pronounced, with a notable increase during the past few years," the New York Fed said in a blog post, in which iy analyzes trends in borrowing by American households each quarter.

While saying that most auto loans were "still performing well," the Fed said 6 million people were at least 90 days late on repaying their car loans.

The swelling delinquencies come at a time when unemployment is low and borrowers typically should be able to make their payments, the New York Times explains.

“That such serious trouble is emerging in a relatively good economy suggests that lenders have been loosening their standards and letting borrowers take on more debt than they can afford,” the Times said.

“Economists fear that if the economy dips into another recession, the already large number of Americans on the verge of losing their cars to repossession — about six million — will swell to record levels,” the Times reported.

In the third quarter, 2 percent of subprime auto loan balances became at least 90 days delinquent, up from 1.6 percent in the third quarter of 2014. In the depths of the recession, in the second quarter of 2009, that rate peaked at 2.4 percent.

The rise in auto lending, particularly the subprime sector, has raised alarms among some regulators in Washington, such as Comptroller of the Currency Thomas Curry and Richard Cordray, head of the Consumer Financial Protection Bureau, the Wall Street Journal reported.

“Lenders, of course, know that subprime borrowers are more likely to become delinquent and charge higher interest rates on those loans. The mistake during the financial crisis was that while lenders expected higher defaults among subprime loans, they failed to anticipate just how high it would rise,” the Journal explained.

“Subprime auto loans have many differences with the subprime housing loans that helped fuel the financial crisis. Cars can be quickly repossessed while home foreclosures can linger for years. Foreclosures can drag down the value of neighboring homes, a type of contagion, whereas the value of one’s car doesn’t change if a neighbor’s car is repossessed. And few people buy cars on credit, hoping to quickly turn around and flip them for a profit,” WSJ.com reported.

Hefty discounts during a robust Black Friday weekend helped boost November U.S. auto sales between 4 percent and 5 percent, automakers reported on Thursday, which could catapult results this year above a record high in 2015.

Industry analysts worried that the record discounts, also called incentives, were both artificially inflating demand and extending the auto sales boom ongoing since the 2008-09 economic crisis, Reuters reported.

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