If last week’s price movement is any indicator, spikes in wholesale prices may finally be slowing down as Tuesday marks the IRS tax filing deadline.

Wholesale prices rose 6 percent in March on a monthly basis and 4 percent from the same period last year, averaging $10,429, according to ADESA Analytical Services’ data. But rates might just be getting back to normal.

Though the auction market is still holding strong overall, this past week marked the lowest level of price increases in the past four weeks, according to Black Book’s Ricky Beggs, who reported that 62 percent of rate changes were increases.

This is very much in line with what Black Book has heard from the lanes, including comment like “good but not as strong as last month” from the Texas market to go along with “steady again” out of Illinois and the “still high” all the way from Washington state, the Black Book editorial director reported in his latest “Beggs on the Used Car Market” video report.

Beggs said though tax season is over, there are two factors “holding the strength of the values up.”

First, dealers are reporting retail inventory is currently low.

Secondly, Beggs said, “The other primary factor might be now that winter weather has finally left us, dealers are anticipating an uptick in traffic within the used market, and they must have some additional inventory.”

Taking a look at the numbers, the average price for cars increased for the third consecutive week, rising $9.

This past week, seven of the 10 car segments saw prices rise, with the upper midsize cars leading the pack (up $74).

On the other hand, the prestige level cars, with a drop of $149, saw one of the biggest decreases this past week.

Trucks continue to show strong price retention with a $31 increase.

And Beggs noted, “This is the first time I can recall that all 14 truck segments were increasing week-over-week.”

Some of the strongest segments were the full-size pickups with a increase of $50, the compact SUVs with a spike of $80, and the minivan wagon segment, which rose by $45.  

“When looking at year ago periods for both the cars and the trucks I am not the least bit surprised to see how much stronger we are today than a year ago where the trucks finished at +$5 and the cars only had four positive changing segments, and overall were at -$14, as these past four to five weeks this year have been amazingly strong,” Beggs said.

These increases among the truck segments is continuing a trend seen through much of 2013 and the beginning of the new year.

In the latest edition of Kontos Kommentary, Tom Kontos said pickups and SUVs experienced particularly strong year-over-year price increases this past month, with the average segment increase for trucks in March coming in at 11.2 percent.

Kontos also touched on a few contributing factors to wholesale price strength in March.

“Off-rental units, which were in greater abundance last March, were a driving factor in this March’s results.  Delayed off-rental supply translated into higher off-rental prices, which in turn contributed to higher overall average wholesale used vehicle prices,” he said. “On top of that, retail used vehicle sales rebounded strongly in March, after being depressed by severe weather in January and February.  The resulting strong demand also contributed to higher overall prices.”

That same severe weather might also help to push prices down in the near future.

“To the extent off-rental volume was hindered by winter conditions and a late Easter, this volume should be forthcoming soon and, along with expected off-lease volume growth, will put downward pressure on prices as seen in previous months,” Kontos concluded.