How it is computed
For every unit in stock, count the days since it arrived. Count the units at or past the line. Divide by the total units in stock. The share is the headline; the list of VINs behind it is what the desk works on Monday.
Why it matters
Every day a unit sits costs money that never appears on the deal: floorplan interest, the price drops it took to finally move, and the fresh unit the store could not buy because this one was holding the capital.
Aging is where gross discipline turns into a loss. A store that holds price on a sixty-day car may be right; a store that holds price on a hundred-and-twenty-day car has usually already lost the gross it was protecting.
How operators read it
- Read the count, not the average age. An average of forty days can hide ten cars at a hundred and fifty, and those ten are the problem.
- Separate recon time from lot time. A unit that spent three weeks in the shop before it was ever on the line is aging for a reason the desk did not cause, and the fix belongs in the shop.
- Ask what each aged unit is telling you about the buy. A lot that keeps producing aged units of one kind has a buying pattern, not a pricing problem.
Questions people ask
Is ninety days the right line?
It is the common one, and the one most pay plans and floorplan terms are built around. The right line for a store is the age past which the store's own history shows the gross is gone. Many operators also watch a sixty-day warning line so the ninety-day line is never a surprise.
Does new inventory age the same way?
It costs money the same way, but new-car aging is shaped by allocation and the manufacturer's programs, so it is read differently. The ninety-day share is a used-lot discipline first.
How A.D.A.M. reads it
A.D.A.M. counts units at ninety or more days by lane and by store and reports the share of the lot that is past the line, with the units behind it. He reads it beside the numbers it trades against, names what the gap is worth, and leaves the decision where it belongs. What an AI advisor should do, and refuse to do.