Automakers and dealers entered March with an estimated 4,127,100 unsold cars and light trucks on hand, a 78-day supply.
It is the highest days' supply for this time of year since 2009, according to the Automotive News Data Center, but was still down from the 88-day supply of unsold stock on hand that automakers and dealers had at the beginning of February.
Days' supply is calculated based on the previous month's selling rate, and thus takes into account not only volume but also outside factors such as inclement weather that affect sales. For comparison, the industry's 101-day supply at the start of March 2009 was only 2,900,600 vehicles because demand was much lower than today.
On a volume basis, inventories are at their highest level since July 2017, when the industry had an estimated 4,196,800 units on hand. Inventories have increased by about 93,000 vehicles from this point a year ago, when automakers had a 74-day supply, and are up 111,600 units from the start of February.
Vehicle stocks topped 4 million units to start March in both 2017 and 2018 as well. In both of those years, they stayed above that level for at least the following two months.
In terms of mix, automakers and dealers reported 1,137,500 unsold cars on hand, a 72-day supply, and 2,989,600 light trucks, an 81-day supply. The 28 percent mix of unsold cars in inventory is below the sales mix for cars in February, which was 30 percent.