Prices for vehicles from fleet lease consignors increased 6.6% in March and are 4.9% higher than a year ago driven in part by a strong spring selling season that boosted the values significantly from February levels, according to KAR Auction Services.

Former fleet vehicles performed the best among the three streams of vehicles sold at auctions and other wholesale channels in March and bested vehicle values from manufacturers or dealers. Average wholesale prices from used vehicles from manufacturers increased 1.6% from February and 9.2% from a year ago. Dealer cars, including off-lease vehicles and trade-ins, were up 3.5% for the month and 0.8% from a year ago.

"This analysis indicates that wholesale values for off-lease units are holding up well despite the overall softening market trend," said Tom Kontos, KAR's chief economist.

March represented a boost from February, where auctions saw more modest gains.

In February, former fleet vehicles fell 1% in value in February and were up 0.4% for the year. Manufacturer vehicles were up 0.6% from January and 8.7% for the year. Dealer vehicle prices fell 2.1% for the month and down 1.6% for the year.

Related: Fleet Consignor Prices Rise 4.1% in January