Inventory analysis: distinguish stock building from demand
Inventory analysis should combine stock levels, turnover, composition and write-down policy. Rising inventory can support growth, protect supply or signal unsold goods. The balance alone does not distinguish these explanations; compare it with the goods’ economic purpose and later movement.
Match inventory with its cost denominator
For a simple goods business, inventory days can be approximated as average inventory divided by cost of goods sold, multiplied by days in the period. Revenue is usually a different denominator because it includes gross profit. State whether average inventory uses two endpoints or a more representative series.
IAS 2 measures inventory at the lower of cost and net realizable value. Its overview also describes cost assignment and recognition as expense when the related revenue is recognized. Read the issuer’s framework and policy before comparing companies using different methods.
Hypothetical example: stock builds faster than sales
Assume cost of goods sold is 360 for a 360-day analytical year, with inventory increasing from 60 to 100. The endpoint average is 80, producing 80 inventory days. Assume the prior comparable measure was 60 days.
| Component | Opening | Closing | Possible interpretation to test |
|---|---|---|---|
| Raw materials | 20 | 25 | Buffer for supply disruption |
| Work in progress | 15 | 20 | Production bottleneck or growth |
| Finished goods | 25 | 55 | Demand shortfall or planned launch stock |
| Total | 60 | 100 | Needs composition and later-sales evidence |
These invented figures show why the total is insufficient. Finished goods account for most of the increase. That supports asking about sell-through, returns and markdowns; it does not prove the goods are obsolete. A new-product launch could also explain the pattern.
Link stock to subsequent evidence
Create a record for the product group, age, purpose of the build, expected release date, subsequent sales and write-downs. Compare management’s stated plan with the later inventory movement. If stock stays high after the planned season, revisit the explanation rather than extending it automatically.
Verify whether acquisitions or currency translation added inventory without current-period operating purchases. Check whether inventory write-downs reduce the balance and affect cost of sales; lower closing inventory after a charge is not the same as healthy customer sales. Also inspect commitments to purchase stock that are not yet included in the balance.
Common errors include using one year-end snapshot for a highly seasonal business, comparing retailers and manufacturers without considering work in progress, and treating low inventory as universally good. A stockout can reduce future sales and service quality even as turnover appears efficient.
This analysis is less useful for businesses with little physical inventory and can be misleading for commodities with large price changes. Separate physical volume, unit cost and product mix when disclosed. Where the necessary detail is absent, preserve competing explanations and do not manufacture an obsolescence estimate.
A further check on the example
Recompute inventory days using a comparable seasonal average when available. If the 100 closing stock follows a large year-end delivery, the two-point average of 80 may overstate typical stock; a pre-season peak can create the opposite problem. Keep the simple calculation as a disclosed approximation and compare it with composition and later movement. A more detailed denominator does not repair a mismatched inventory population, so first verify that both numerator and cost of sales cover the same products and entities.
FAQ
Does higher inventory days mean demand is weakening?
Not necessarily. Planned supply protection or a launch can increase days. The explanation should be tested against composition and later sales.
Can a write-down make inventory quality look better?
It can reduce the carrying amount without selling goods. Track write-downs and physical movement separately when available, and avoid interpreting the lower balance in isolation.