With their values down 10.5 percent, entry-level cars have shown the most depreciation of any segment since the beginning of May, according to Black Book. And last week, that downhill movement only continued.

So, given how the supply of off-lease and rental cars is ramping up at auctions — which could potentially drive these prices down further — these soft entry-level car prices are worth monitoring, Black Book says.

Entry-level car values were off 0.93 percent ($61) last week, the company noted, meaning this segment was the biggest decliner among the 24 that Black Book tracks.

“The entry-level car segment continues to drop lower even after experiencing the most depreciation in the last four months,” Anil Goyal, vice president of automotive valuation and analytics, said in Black Book’s latest Used Car Market Insights report.

“It will be interesting to see trends on late-model vehicles as more off-lease and rental cars are beginning to show up at auctions,” he added.

For instance, take this comment Black Book personnel gathered from a Texas man in the lanes last week: “More and more rental cars are showing up in this area. We should see what impact this has over the next few weeks.”