Every year-end brings the same scene: the auditor pulls an inventory listing, sorts it by last movement date, and asks why items that have been inactive for three years are still on the balance sheet at purchase cost. The CFO then improvises a provision, often as a rough estimate and often in the last week of the close, and the result moves by several points.
This is not an accounting problem. It is a configuration and process-discipline problem. A well-configured ERP detects slow-moving stock all year long, proposes a provision consistent with a written method, posts the write-down and the reversal automatically, and keeps a trail of every decision. This guide is written for CFOs and financial controllers at mid-sized manufacturing and distribution companies. It covers the rule, the detection, the configuration and the sell-through.
Why Slow-Moving Stock Is a Year-End Risk
Stock that no longer turns is an asset whose recoverable value is uncertain. Three risks compound.
An earnings risk. A late write-down concentrates in a single period losses that built up over several. The closing result takes a sudden hit that management never flagged to the bank or the shareholders.
An audit risk. Inventory is a classic area of auditor attention: valuation, existence, completeness of the write-down. A provision without a documented method, or a method applied differently from one year to the next, leads to proposed adjustments and sometimes to qualified opinions.
A planning risk. Inventory inflated by dead stock distorts coverage, working-capital ratios and purchasing decisions. The ERP keeps calculating requirements for items nobody will ever sell.
What they have in common: all of it is visible in the ERP data months before the close. You only have to use it.
The Accounting Rules: Cost Versus Net Realisable Value
The Principle: The Lower of the Two
Under IFRS, IAS 2 Inventories requires inventory to be measured at the lower of cost and net realisable value (NRV). NRV is the estimated selling price in the ordinary course of business, less the estimated costs of completion and the estimated costs necessary to make the sale. US GAAP (ASC 330) applies the same lower-of-cost-and-NRV test to inventory valued under FIFO or average cost.
National frameworks follow the same logic. In France, for example, the entity must assess at each closing date whether there is any indication of impairment, within the framework set by the French Commercial Code (article L123-18) and the ANC chart-of-accounts regulation.
The logic is identical everywhere: if what you can reasonably recover from an item is lower than what it cost, you recognise the difference. This guide does not invent any threshold: neither IAS 2 nor national chart-of-accounts rules prescribe a percentage by age. It is up to the company to define and justify its own method.
Book Write-Down Versus Tax Deduction
This is the distinction many ERPs do not handle natively. The accounting write-down answers the true-and-fair-view requirement. Tax deductibility follows its own rules, which vary by country. In France, for instance, the administrative guidance on inventory write-downs (BOI-BIC-PDSTK-20-20-10-20) states that stock is valued at cost or at market value if lower, and that the loss in value must in principle be established from actual evidence.
The practical consequence: a flat provision calculated by category and age may be accepted if it approximates reality closely enough, but tax authorities generally reject uniform percentages applied without regard to product characteristics. A company holding detailed ERP data is poorly placed to argue for a rough approximation.
Keep two levels in your configuration: the book provision, and, if it differs from the tax deduction, the off-ledger adjustment to be carried to the tax return. Check the local rules with your tax adviser.
Write-Down Methods: Age, Turnover, Item-by-Item
Three approaches coexist, and most companies combine them.
- By age: a rate that increases with the time elapsed since the last movement or last issue. Simple to automate and easy to explain, but blind to items that legitimately sleep (safety parts, seasonal goods).
- By turnover or coverage: stock is compared with foreseeable consumption. An item whose coverage exceeds a defined horizon is partially written down on the excess portion. Finer, but dependent on the quality of the consumption history.
- Item by item (individual analysis): for high-value stock, NRV is estimated reference by reference (buy-back price, scrap price, revised list price). This is the most defensible method, reserved for the costliest references.
In practice: an automatic rule for the bulk, an individual review for the top quartile by value, and a list of justified exceptions (long-life spare parts; see our guide to MRO spare parts management).
Detecting Slow-Moving Stock in the ERP
Before provisioning, you need a reliable snapshot. Three indicators, available in practically every ERP, are enough.
The last movement date. Per item and per warehouse, the last issue date (sale, consumption) tells you more than the last receipt date. An item received yesterday that has not been issued for two years is dormant.
Stock ageing. A report by bucket (0-90 days, 90-180, 180-365, over one year), in quantity and in value. In an ERP that manages cost layers (FIFO), ageing is that of the layer. Under average cost, it is derived from receipt dates.
Days of coverage. Available stock divided by average daily consumption. Beyond a horizon you define for your business, the excess is a write-down candidate.
Two prerequisites determine reliability: a clean physical inventory (a wrong quantity gives a wrong provision; see our guide to initial inventory and cycle counting) and consumption data free of artificial movements. An inter-warehouse transfer must not reset the age to zero, which some configurations do by default.
Configuring the Provision
The Rate Matrix
The matrix crosses an age or coverage rule with a write-down rate, possibly by item family. Here is an example structure, purely illustrative: the rates must be calibrated on your actual realisation history, not copied.
| Age since last issue | Provision rate (to calibrate) | Justification to keep |
|---|---|---|
| Under 12 months | 0% | Normal turnover |
| 12 to 24 months | rate A | Observed discount history over this period |
| 24 to 36 months | rate B | Observed buy-back or clearance value |
| Over 36 months | rate C, up to 100% | Sale unlikely, scrap value |
What matters is not the number but traceability: where does rate A come from? An answer such as “average of the discounts granted over the last three financial years” stands up in front of an auditor and a tax inspector. “It’s what we’ve always done” does not.
Write-Down and Reversal Accounts
In most charts of accounts, an inventory write-down is recognised as an operating expense, against an inventory allowance (contra-asset) account, with a reversal when the cause disappears (sale, sell-through, NRV recovery). In the French chart of accounts, for instance, the allowance sits in class 39. Check the accounts with your accountant: the ERP point of attention is that the write-down and the reversal are separate, symmetrical entries, never a net balance.
Automating the Close
The target pattern is the same whatever the ERP:
- A provision run executed at the closing date, item by item, according to the matrix.
- A control report detailing items, quantities, cost, rate and provision.
- An accounting entry generated automatically, reversed or released in the following period.
- A list of manual adjustments, traced with author, date and reason.
What the main ERPs offer, without claiming to be exhaustive and with an invitation to check your version:
- SAP S/4HANA: lowest-value valuation provides mechanisms to revalue inventory based on criteria such as turnover or age, with postings generated. Configuration requires joint work between finance and logistics.
- Odoo: to our knowledge, there is no native module for inventory obsolescence provisions. The usual approach: a valuation and ageing report, then a provision entry generated by a module or a manual journal reversed the next period.
- Sage X3: ageing and coverage data are usable; the posted provision goes through an end-of-period process configured with the partner.
- Dynamics 365 Business Central: inventory and turnover reports are usable, with the provision most often posted through a general journal, with or without an extension.
The finding is consistent: the calculation is cheap, the difficulty is making it repeatable. For the underlying valuation mechanics (FIFO, weighted average, standard cost), see our inventory valuation article: the write-down applies on top of the value produced by the chosen method; it does not replace it.
From Provisioning to Sell-Through
A provision is not a solution, it is a finding. The real gain is to sell the stock through, which removes both the risk and the carrying cost. Four exits, each with its own entries.
Reclassification. The item moves to second grade or clearance status, with a revised price. The ERP must handle a quality code or a dedicated warehouse so that NRV is readable.
Discounting or bulk sale. Selling below cost makes the corresponding provision reversal appear: the negative margin is neutralised by the release. Reporting that shows both avoids the false impression of a loss-making business.
Donation. Under French VAT guidance (BOI-TVA-DED-60-30), for example, no VAT adjustment is needed for the donation of unsold goods to recognised public-interest bodies, provided the recipient issues a certificate with a detailed inventory (date, nature, quantity). The ERP must therefore be able to produce that donation inventory. Other countries have their own donation and VAT or sales-tax rules.
Scrapping. The same guidance indicates that destroying goods that have become unusable or unsaleable, recorded in the books, does not in principle trigger a VAT adjustment, provided the destruction can be evidenced (a destruction certificate, for example). Keep the document in the ERP, attached to the issue movement. For special cases (regulated sectors, destruction of products under warranty), have the treatment validated by your tax adviser.
Dashboard: 5 KPIs
Five monthly indicators, drawn from the same data as the provision:
- Slow-moving stock as a % of total value: value of items with no issue for more than N months, over total stock. N is your threshold, set by family.
- Average coverage in days, and the share of stock whose coverage exceeds the set horizon.
- Write-down rate: cumulative provision divided by gross stock value. Its trajectory matters more than its level.
- Slow-moving sell-through rate: value of slow-moving stock issued during the month (sale, donation, scrap) over opening slow-moving stock.
- Realisation gap: actual selling price of cleared items compared with the NRV used. It measures the quality of your matrix.
If KPI 5 is systematically positive (you sell better than expected), your rates are too prudent. If it is negative, you are under-provisioning.
Common Mistakes and Countermeasures
1. Provisioning only at year-end. Countermeasure: run the calculation monthly in simulation mode, and post only at closing or quarterly.
2. A matrix without justification. Countermeasure: document the origin of each rate and review it every year against the discounts actually observed.
3. Forgetting the reversal. Items sold through leave an orphan provision. Countermeasure: recalculate the provision item by item, so the reversal falls out naturally.
4. Ageing distorted by transfers and stock counts. Countermeasure: configure the movement types that preserve the original date, and exclude inventory adjustments from the last-issue calculation.
5. Not separating book from tax. Countermeasure: document any difference and handle it as an off-ledger adjustment, with a reconciliation table kept in the ERP or in the closing file.
Pre-Close Checklist
- The year-end physical count is reconciled with ERP stock, with differences valued and posted.
- The ageing and last-issue report is extracted at the closing date and archived.
- The rate matrix is approved by the finance department and unchanged, or the change is justified.
- High-value stock has had an individual NRV review.
- The provision is calculated, and the detail report is reconciled with the accounting entry.
- The year’s reversals are analysed and explained.
- Manual adjustments are traced (author, date, reason, supporting document).
- Slow-moving stock exits (donation, scrap) have their tax supporting documents.
- The book/tax difference is identified and carried forward.
- The five KPIs are shared with the auditor together with the method.
To build this control into your year-end calendar, see our ERP year-end close checklist for the CFO, then download our ERP evaluation grid to check whether your current ERP covers these closing needs. To scope a provision configuration project with your integrator, contact DigitsLane.
