The average price of used LCVs sold at auction increased to £9,375 in May, the third-highest level on record for online sales, according to BCA.
The auction firm said this was a £346 (3.8%) increase compared with April.
It said values continued to beat market expectations by a significant margin, with prices averaging over 107% above guide prices during the month.
Conversion rates are also said to have remained strong, with particular demand for younger, retail-quality vehicles.
BCA UK COO Stuart Pearson said: “During 2021 we have seen used LCV values accelerate significantly, as the rise in online shopping continues to drive demand from the home delivery, courier and final mile sectors.
“Looking ahead, with ongoing supply pressures in the new van market, we expect that demand in the wholesale arena will typically continue to outstrip supply and values will remain extremely robust.
“Whether this continues to reach the dizzy heights that we’ve seen over the last 18 months is hard to predict, but after everything that we’ve seen happen in the market, nothing should come as a surprise.”