Inventory and Stock Data: When the Shelf and the Books Disagree

Why Stock Data Matters to the CFO

For most product businesses, inventory is one of the largest items on the balance sheet. It decides how much cash is free, how much can be promised to customers and what margin the income statement will show. Yet the figure finance reports is only as good as the stock records behind it, and those records change thousands of times a day through receipts, sales, returns, transfers and corrections.

When the records drift from reality, the cost does not appear as an inventory problem. It appears as missed sales, emergency purchases, discounts to clear surplus and write-offs at year end. The CFO sees the symptoms in four different places and rarely gets a single explanation.

Stock Counts That Do Not Match the Shelf

Record errors are far more common than most teams assume. In a well-known study published in Management Science, Nicole DeHoratius and Ananth Raman examined nearly 370,000 inventory records from 37 stores of one retailer and found 65% of them to be inaccurate. That retailer was not careless. Stock records drift because of everyday events: a receipt booked to the wrong item, a return put back on the wrong shelf, a damaged unit never written off.

The commercial effect is direct. If the system believes there is stock, nobody reorders, and the customer finds an empty shelf or a cancelled order. If the system believes there is none, the item is reordered while the old units sit unseen. Both mistakes cost money, and both are invisible in a report that only shows totals.

Out-of-Stocks and Overstocks: Two Sides of the Same Error

IHL Group, which has measured this for many years, estimates in its 2026 study that out-of-stocks and overstocks together cost retailers worldwide about 1.7 trillion dollars, around 6% of retail sales. Out-of-stocks are lost revenue. Overstocks are lost margin, because surplus goods are sold at a discount, written off or stored at a cost.

Distributors and manufacturers face the same pattern with different names. A distributor runs out of a fast mover while carrying months of a slow one. A manufacturer cannot ship a full order because one component is wrong in the system. The root cause is often the same: stock data that nobody trusts enough to act on.

Write-Offs and Valuation: Where Margin Disappears Quietly

Write-offs are the moment an error becomes a loss on paper. Expired, damaged or missing goods are removed from the books, often in one large adjustment at the end of a period. By then it is too late to ask why. The loss may have started months earlier with a wrong receipt, a return booked as sellable or a transfer that never arrived.

Valuation adds a second layer. If the cost on the item is out of date, the margin on every sale is wrong, even when the stock count is right. A product sold below its real cost looks profitable in the sales report and quietly reduces gross margin. Returns make this worse, and the National Retail Federation projected US retail returns at close to 17% of sales in 2024. Every returned unit has to come back into stock at the right value.

Slow Movers and Tied-Up Cash

Slow-moving stock is the most patient form of leakage. It does not fail an audit or stop a shipment. It simply sits, ages and eventually has to be discounted or written off. Meanwhile it ties up cash and warehouse space that could serve products customers actually want.

Inventory errors rarely stay in the warehouse. They usually begin in the product master data, with wrong units, duplicate items or outdated costs, and they surface in sales as revenue leakage.

What korppi Delivers

korppi reads your stock and sales exports side by side and shows where inventory errors are costing revenue or margin, with the invoice lines and stock movements behind each finding. You see the amount at risk, which items and locations it concerns and who owns the fix, instead of a single adjustment at year end.

The korppi Data Health Report gives you that picture once, with a value on every problem. korppi Revenue Intelligence keeps it current with every new export. Every figure is calculated from your own data, AI explains the results without inventing numbers, and a read-only export is enough. korppi never writes to your system.

Start With a Data Health Report

The fastest way to know what your stock data is costing you is to look at it with your sales next to it. Request a Data Health Report for your own data, or request a demo to see korppi first. See also e-commerce and marketplace data.

Frequently Asked Questions

Sources

1. Inventory Record Inaccuracy: An Empirical Analysis · Management Science (INFORMS), DeHoratius and Raman, 2008
2. The 2026 Inventory Distortion Study · IHL Group, 2026
3. 2024 Consumer Returns in the Retail Industry · National Retail Federation and Happy Returns, 2024