Several prominent voices sound the alarm on subprime auto lending, sparking new concerns about the fragility of credit-worthiness in America.

In a new study, Transunion announced that “Payment Shock” is possible should the Federal Reserve raise interest rates, and thus the cost of borrowing, for Americans. The credit monitoring company calculated the impact of a 0.25% interest-rate hike in December. Transunion concludes that 92 million “credit active” consumer may face a payment increase. However, roughly 10%, or 9.3 million borrowers, may be unable to absorb the cost of payment increases due to a rate hike. The firm says that roughly 4.85% of all subprime auto loans are at least 60 days late as of August 2016. By comparison, that rate sat at 4.14% in August 2015. Transunion says this is the highest level of delinquency since January 2010.

Angelo Young at Salon projects that the subprime lending business in the auto industry could soon collapse. According to Young’s analysis, auto loans comprise $1.1 trillion of household debt in the U.S. During the second quarter of 2016, Americans added another $32 billion in auto loan debt, according to the Federal Reserve Bank of St. Louis. Young says that economists are very concerned about Americans driving around in vehicles that are “underwater” on their loans. This means that the vehicle is worth less than the cost of their total outstanding loans. S&P Global Ratings says that roughly one out of every five subprime borrowers are currently late by 60 days or more on their payments.

Meanwhile, the delinquency rate of all subprime loans that have been repackaged into marketable bonds between 2010 and 2015 has hit their highest rate of delinquency since the mid-1990s

Moody’s Global Credit Research team released a report on Oct. 20, raising concerns about the stability of smaller subprime auto lenders. The rating agency says that larger organizations that have more diverse clientele outside of subprime can absorb financial problems. (See also: Subprime Auto Loans: What Borrowers Should Know.)

Smaller units can face greater losses due to weaker market conditions, higher risks and credit crunches.

"Smaller firms often depend heavily on asset-backed securities (ABS) financing, which may not be available in adverse market conditions," said Moody's analyst, Peter McNally, in a statement. "In addition, auto ABS funding is for relatively short terms, which concentrates debt maturities, raising the risk that a large portion of funding could mature in a difficult refinancing environment."

The ongoing concerns about the subprime market have drawn attention to lenders like Nicholas Financial Inc. (NICK). The stock fell by 1.48% on Thursday as investors weigh the stability of the market. NICK stock is off 14.08% on the year and is off 26.39% from its 52-week high. (See also: Subprime Auto Delinquency Rates on the Rise.)

Investors in the stock should continue to monitor delinquency rates as a proxy for the stability of the greater subprime auto market. Increased delinquency rates may signal a new subprime bubble set to burst. (See also: Auto Loans the Next Subprime: Jamie Dimon.)

Want to learn how to invest?

Get a free 10 week email series that will teach you how to start investing.

Delivered twice a week, straight to your inbox.