Used vehicles at both ends of the GVW spectrum are making up the largest share of transactions through three quarters of 2015, and Class 3 trucks logged the highest growth trajectory, according to an IHS Automotive report.

A strong third quarter of used commercial vehicle transactions took the yearly total to 579,000 units for a 4% gain over the same period in 2014. Year-to-date transactions were 10.9% lower than the record level achieved during the first nine months of 2011.

Used sales reached 200,000 transactions in the quarter, which represents a 10.7% increase from July to September of 2014. Used vehicle transactions represented 51.4% of total commercial vehicle transactions in the quarter, which was the fourth best quarter on record.

"With the continued high level of new commercial vehicle registrations to fleets operating 500+ plus units, the trade backs provided by these large fleets provide a ready source of used commercial vehicles that are highly desirable to small and mid-size fleets," said Gary Meteer, director of commercial vehicle solutions for IHS Automotive.

"The main challenge continues to be the location where the used trucks are available and the ability of small- to mid-size businesses to find the configuration that fits their needs to either replace older equipment or add equipment to their fleet."

Large fleets with at least 500 units accounted for 36% of new commercial vehicle registrations during the first nine months of 2015. These same large fleets accounted for about 17% of the commercial vehicles registered to operate on highways at the end of September.

"Each large fleet has a planned life cycle for their new equipment and when the life cycle has been met, the vehicle is transitioned to the used market; thereby providing a steady flow of good used equipment for the small and mid-size fleet," said Meteer.

Year-over-year increases in the quarter were best for used Class 3 vehicles, up 16.1%, followed by Class 6 and Class 8 vehicles, up 16% and 10.5% respectively. Used transactions of Class 8 vehicles were just over 70,000 units and they represented 35.1% of total used transactions, followed by Class 3 vehicles with 66,000 units and 33.1 percent share.

Year-to-date data shows the strongest growth in Class 3, which increased 11.2% to 187,000 and made up 32.3% of sales. Class 8 made up 36.4% of sales, and has slipped 1.1% in 2015. Class 4 had the most notable decline of 4.2% to 54,000 for the year. Class 5 was the smallest niche at 32,000 units transacted.