Used fleet vehicle values rose by 4.2% (£303) and were just above the same month in 2014, according to Manheim.
The figures show that the average de-fleeted vehicle was worth £7,461 in June, with an average age of 47 months – four months younger than the average vehicle sold in May, and three months below June 2014.
It says that while much of the increase in values can be attributed to younger stock, there are other factors. Mini MPV values, for example, are 4.8% (£231) up on figures from June 2014, despite the stock age profile being exactly the same, at 61 months.
Compared with May, average mileage for de-fleeted stock fell by 5.4% (3,313 miles) and it was also 1.4% (796 miles) down on the same month last year.
Average mileage of de-fleeted supermini and medium family cars was 12.6% (4,150 miles), and 3.5% (2,079 miles) down on June 2014, whereas average mileage for compact executive and executive models was up 7.4% (5,204 miles) and 5.2% (3,605 miles), respectively.
Valuation services manager at Manheim Daren Wiseman said: “The quality of de-fleeted stock remains high and vehicles in all segments are attracting selling prices to reflect that fact. Younger cars with lower mileage add even more appeal for buyers, who are keen to snap up the best stock.”