Last month, the average interest rate on a new-vehicle loan reached its highest level since the third quarter of 2009, as federal rate increases made last year trickled down to vehicle finance, Edmunds said last week.

In February, the average interest rate on a new-vehicle loan was 5.2 percent. The last time the rate was that high was in the third quarter of 2009, when it was 5.6 percent. In February 2017, it was 4.9 percent, Edmunds said.

The federal benchmark interest rate reached 1.5 percent in December after three Federal Reserve rate hikes last year of 0.25 percentage point each. The Federal Reserve is expected to increase rates three times in 2018.

"We're starting to see a trickle-down effect from the rate increases happening at the federal level," Jessica Caldwell, executive director of industry analysis, said in a statement.

In between

A decline in the number of auto loans with a 2 to 3 percent interest rate and an increase in loans with a 4 to 7 percent rate drove the overall rise, Edmunds said.

"You get the folks who have really good credit that get some sort of interest rate subsidy from the automaker and the folks that are in between," Caldwell told Automotive News. "Those are the ones that are being affected."

The "in-between" borrowers have historically been in the 3 percent interest range, but now many of them are likely in the 4 to 5 percent range, she said.

In February, the percentage of auto loans with interest rates above 7 percent increased 1 percentage point vs. a year earlier to 19 percent. Borrowers with an interest rate of 10 percent or higher are likely subprime, but there are borrowers with interest rates above 7 percent that are not necessarily subprime, Caldwell said.

Borrowers with interest rates of 0 to 2 percent tend to fall into the prime tier. The percentage of loans with an interest rate of 0 to 2 percent rose 1 percentage point to 22 percent in February, according to Edmunds.

Record leasing

Higher interest rates and an influx of lease returns lifted lease penetration to an all-time high of 33.5 percent last month, according to Edmunds.

Leasing has hovered around 29 percent in recent quarters, so the penetration increase was unexpected, Caldwell said. "A lot of folks had expected leasing to flatten out in 2018, kind of like what we saw in 2017," she said.

"As average transaction prices and interest rates rise, we're likely going to see more consumers explore the option of leasing," she said in the statement. "In some cases this is a result of consumers simply seeking a way to cut down monthly payments, but for many others, this the only option available when they discover that they can no longer afford the costs of a new vehicle."

February is typically a high leasing month, Caldwell said. She doubts that leasing will stay as high as 33.5 percent, but as interest rates continue to increase and more consumers look to leasing to offset the monthly payment, lease penetration will stay within the 30 percent range.