Inventory Write-Downs for Used Car Dealers: A Practical Guide

An inventory write-down is the entry you make when a vehicle on your lot is worth less than what you have booked it at. You reduce the car’s carrying value to its current market value, and the difference hits your income statement as a loss in the current period, usually through cost of goods sold (COGS). For a dealer, the hard part is not the entry. It is knowing which cars need it, proving the number, and seeing the real cost of each unit before the loss surprises you.

This guide covers when to write down a vehicle, how to support the number, what the entry looks like, how taxes come into it, and how to build a routine so write-downs stop being a year-end scramble.

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TL;DR

Value each vehicle at the lower of its total cost or its market value. When market falls below cost, write the car down and book the difference to COGS in the current period.
Do it unit by unit, with evidence such as current wholesale or market data, not with blanket percentages or hunches.
Aging, damage and market drops are the usual triggers. A regular aged-unit review catches them early.
A write-down only works if the cost on the car is complete: purchase price, transport, recon and fees assigned to the VIN.
Have your CPA confirm your inventory method before you change anything. Switching methods can require filing IRS Form 3115.

What a write-down means on a dealer’s books
The rule: lower of cost or market
When to write a vehicle down
How to support the number
A worked example
The tax angle
Write-downs and your other numbers
Build a routine so it is not a year-end scramble
Our perspective: you cannot write down what you cannot see
Where Loturn fits
FAQ
Sources

What a write-down means on a dealer’s books

The general definition is simple: a write-down is an accounting adjustment that lowers the book value of an asset when its fair market value has fallen below its recorded value. For a used-vehicle dealer, the asset is each car, truck, RV, boat or trailer sitting in inventory.

Two terms get confused, so keep them apart:

Write-down: a partial reduction. The car is still on the lot and still carried at a lower value.
Write-off: the full removal of value, for example a unit that was stolen, destroyed or otherwise gone. Our stolen vehicle accounting playbook covers that scenario step by step.

A common question is whether this loss is an operating expense. For a dealer, inventory write-downs go against current margins rather than into some separate impairment bucket. Impairment is for things like real estate and equipment. The loss on a vehicle lands in COGS, so it reduces your gross profit on the books for the period.

The rule: lower of cost or market

The working standard for most dealers is lower of cost or market, usually shortened to LCM. One CPA firm that works with auto dealers describes LCM as valuing used cars and parts at the lower of original cost or current market value, which reflects how quickly used vehicles depreciate.

Their example is worth repeating because it is the whole concept in one line. A used car sits on the books at $15,000 and its market value drops to $12,000. The dealer writes off $3,000 to COGS so the inventory is properly valued.

The same source adds three practical points:

Market value is typically identified using industry valuation guides and live market data.
The adjustment is made item by item, not across the whole lot.
Anticipated or historical defect percentages are not a basis for adjusting value. The write-down needs evidence of an actual market decline or subnormal condition.

For federal tax purposes, the IRS explains in Publication 538 that businesses where merchandise is an income-producing factor must keep an inventory and generally use an accrual method for purchases and sales. If you are unsure which method applies to your lot, that is a conversation for your CPA, not a guess.

When to write a vehicle down

A write-down needs a trigger and a record of it. The most common triggers on an independent lot:

Aging inventory

Used vehicles lose value while they wait. Wholesale prices move, newer model years arrive, and a unit that was priced right at day 10 is overpriced at day 90. Industry-wide, Cox Automotive reported that used-vehicle inventory reached 2.26 million units with a 48-day supply as of October 6, 2025. When supply is deep, aged units are the first to lose ground against the market.

Many dealers set review thresholds at 60, 90 and 120 days. Triggered alerts help here: one comparison of dealership tools describes inventory aging automation as workflows that watch days in stock and notify managers at set thresholds. Whatever tool you use, the point is that a person looks at each aged unit and decides.

Market drops

Some segments reprice fast. If a model you hold deep in starts selling 15% lower at auction, every unit you own of that model deserves a fresh look, one VIN at a time.

Damage or subnormal condition

Hail, a failed inspection, a title problem found late, a flood history, a mechanical issue that recon cannot economically fix. If the condition lowers what the car will bring, document it with photos, estimates and dates.

What is not a trigger

A feeling that some cars on the lot will probably be worth less someday is not a trigger. The guidance above is clear that anticipated percentages do not support an adjustment. Write down what has declined, with evidence.

How to support the number

A write-down is only as good as the paper behind it, especially if an auditor, lender or the IRS asks. For each unit, keep:

The full cost basis on the date of the adjustment
The market value you used, with the source and the date you pulled it
Notes on condition if damage is the reason
Who approved the entry

Market evidence can come from wholesale guides, recent auction results, live retail market data, or an independent appraisal. Pick sources you can print or screenshot, and use the same ones consistently. Accountants who work with dealerships often point to this kind of pricing reference as the thing that makes the entry defensible.

If your cost basis is shaky, the whole exercise fails. A car carried at $15,000 when real cost, with transport and recon, is $16,800 will show the wrong loss. Our guides on per-VIN inventory costing and recon work-in-process accounting explain how to get cost onto the right vehicle before you ever compare it with market.

A worked example

Say you bought a 2021 crossover at auction for $14,200. Here is how the cost stack and the write-down might look. These numbers are illustrative.

Item	Amount
Purchase price	$14,200
Auction and buyer fees	$450
Transport	$350
Recon (tires, brakes, detail)	$1,300
Total carrying cost	$16,300

Ninety-five days later, comparable units are retailing lower and your wholesale exit value is $14,800. Under LCM you compare $16,300 against $14,800 and write down the $1,500 difference.

The entry in plain terms:

Account	Debit	Credit
Cost of goods sold (inventory write-down)	$1,500
Used vehicle inventory		$1,500

The car now sits at $14,800. If you later sell it for $15,900, your recorded gross is $1,100 on that unit, because the loss was already taken. The write-down did not create the economic loss. It moved its recognition to the period when the market actually declined.

A few cautions on this example. Whether you compare against wholesale or retail-based value depends on your accounting policy and your CPA’s advice, so settle that once and apply it consistently. And some dealers keep a separate write-down contra account rather than crediting inventory directly. Either way, the reduction should be traceable by VIN.

The tax angle

Writing inventory down to market when it has clearly declined can reduce taxable income in the period it is recognized. Tax professionals who serve dealers frame LCM as a tax planning tool as much as an accounting rule, because it brings the loss forward and can ease cash flow when the market tightens.

Two cautions:

Method changes need paperwork. Moving to LCM from another inventory method typically requires filing IRS Form 3115, per the same source. Do not switch quietly in the middle of a year.
Evidence beats optimism. Adjustments without proof of market decline invite questions. Keep the file.

This is the point where your CPA earns their fee. Ask them which inventory method your dealership uses, whether LCM applies to your entity, and how they want write-downs documented at year end. For a broader view of how method choice changes profit, this overview of inventory accounting methods is a useful companion to that conversation.

Write-downs and your other numbers

A write-down touches more than one report:

Gross profit: the loss hits COGS, so monthly gross drops when you book it, not when the car sells.
Floorplan: a car written down is often one that has been financed for a long time. Interest has been stacking on top of the original cost. See how to analyze floorplan utilization per VIN to spot those units sooner.
Borrowing base and lender reporting: lenders look at inventory value. A clean, documented write-down is better than a surprise.
Sales forecasting: if aged units keep needing write-downs, your buying or pricing is off. Treat repeated write-downs as data.

And remember that a write-down is a bookkeeping reflection of a recon, pricing or buying problem. The fix is upstream. If your inventory system ties each posting to the vehicle, the same record that supports the write-down also shows where the money leaked. For example, a deal posting checklist helps keep gross consistent after the sale, so you can compare what you expected with what you booked.

Build a routine so it is not a year-end scramble

Here is a monthly process that fits a small lot without a controller.

Run an aging report for every unit by days in stock and total cost.
Flag units past your threshold, such as 90 days, plus any with a known market drop or damage.
Pull market evidence for each flagged VIN and save it with the date.
Compare cost to market and calculate the difference unit by unit.
Post the entry for units where market is below cost, with a note on why.
Decide the action. Reprice, wholesale, move to another lot, or hold with a reason.
Reconcile. Make sure the inventory subledger ties to the general ledger after the entries.

Physical verification matters too. A write-down on a car you cannot find is a different problem. A mobile inventory audit confirms what is on the lot, in what condition, before you book anything.

Common mistakes

Writing down by percentage across the whole lot
Leaving recon and transport off the cost, so the write-down is understated or overstated
Booking the loss only when the car sells
No saved market evidence
Changing methods without your CPA and without Form 3115 when it is required
Mixing up stolen or missing units with ordinary write-downs

Our perspective: you cannot write down what you cannot see

We built Loturn for independent used-vehicle dealers because we kept hearing the same frustration: costs scattered across spreadsheets, text messages, receipts and a general accounting package that sees the lot as one big number. Write-downs expose that problem. To decide whether a car needs a write-down, you need its true cost today, and most dealers cannot say what that is without an hour of digging.

Our view is that write-downs should be a routine, small adjustment, not a painful event. That happens when every cost lands on the vehicle as it is incurred: the purchase price, the transport, each recon invoice, floorplan interest. When that is true, an aged-unit review takes minutes. You see cost, you see days in stock, you compare with the market, and you post the entry against the right VIN.

We also think dealers should see profit before the sale, not after. A car carrying $16,300 of cost that the market will pay $14,800 for is a known loss on day 95. It is better to know that on day 60 and act. Seeing profit per car, live, is the reason our accounting is native double-entry with an automotive chart of accounts rather than a bolt-on to generic software.

Your CPA decides method and tax treatment. Our job is to make sure the data they work from is complete and tied to each VIN.

— Eric Dosset

Where Loturn fits

If you track costs in several places and write-downs feel like guesswork, Loturn puts per-car cost, inventory, accounting, CRM and reporting in one platform. Plans are flat monthly pricing: Flipper at $99 per month, Dealer at $349 per month and Multi-Lot at $699 per month, with free data import and onboarding support. See the plans and pricing to find the size that matches your lot.

FAQ

Is a loss on inventory write-down an operating expense?

For a dealer it is generally recorded in cost of goods sold, so it reduces gross profit in the period you recognize it. It is not treated like a separate impairment of equipment or real estate. Ask your CPA how your financial statements should present it.

How do I write off obsolete inventory?

First separate the two cases. If a vehicle has lost value but is still sellable, write it down to market. If it is gone entirely, such as stolen or destroyed, write off the full carrying cost and follow the insurance or claim process. Document the reason and the date in both cases.

Can I write down all my aged cars by a set percentage?

No, that is not a sound basis. Guidance for dealers says LCM adjustments are made item by item and require evidence of market decline or subnormal condition, not anticipated or historical percentages. Review each VIN against current market data.

Do I need IRS approval to use lower of cost or market?

Changing an accounting method typically requires filing IRS Form 3115, according to dealer tax advisers. Whether you need it depends on your current method and entity. Talk to your CPA before making the switch.

How often should I review for write-downs?

Monthly is a good rhythm for most independent lots, with a year-end review before your books close. Units past your aging threshold, and any model whose market has moved sharply, should be checked as soon as you see the change.