Buying is not yet consuming, and paying is not yet selling. Stock variation attaches to result the value of goods actually issued or consumed during the year. A false quantity, inconsistent unit or midstream cost-method change immediately distorts margin.
The value bridge
- Validated opening stock.
- Purchases and admissible entry costs.
- Returns and reductions reconciled.
- Physically counted closing stock.
- Consistent cost method.
- Issues, losses and adjustments evidenced.
- Current value and impairment controlled.
1. Understand trading mechanics
For merchandise, cost issued can be read simply as opening stock + net period purchases − closing stock. In the normalised CPC, purchases resold or consumed incorporate variation in the prescribed headings.
| Example | MAD |
|---|---|
| Opening stock | 80,000 |
| Net purchases | 300,000 |
| Closing stock | 95,000 |
| Cost of merchandise issued | 285,000 |
| Sales | 450,000 |
| Illustrative gross margin | 165,000 |
The example omits other entries, tax, costs and impairment. It shows why overvaluing closing stock by MAD 10,000 also overstates margin by 10,000.
2. Choose an accepted valuation method
The CGNC values identifiable goods individually. For interchangeable goods it accepts weighted average—after each receipt or over the storage period—and FIFO.
| Method | Practical effect |
|---|---|
| Individual cost | each object keeps its own cost |
| Average after receipt | new average after each intake |
| Period average | weighted average over storage duration |
| FIFO | oldest cost leaves; latest remains |
| LIFO/standard management cost | restatement required for CGNC statements |
A business may manage with another internal indicator, but statements return to an accepted, consistent method.
3. Separate quantity and value differences
Explain units first, then value. Otherwise a case/unit error hides inside a supposed cost problem.
- Freeze date and movements.
- Compare system and physical quantity by reference.
- Check units and conversions.
- Identify receipt, sale, transfer, return, damage and theft.
- Approve quantity adjustment.
- Apply cost under the method.
- Analyse current value and impairment separately.
Negative cost, negative quantity or impossible margin is an alert to investigate, not overwrite.
Never correct margin by editing stock
Closing stock comes from inventory and method. Adjusting value to reach a preferred percentage reverses the reasoning and weakens statements.
4. Control margin without believing the dashboard blindly
Reconcile purchases to suppliers, issues to sales and closing stock to count. Compare margin by family and rate changes, evidencing promotions, losses and mix.
- Margin falls: cost, discount, waste, unit or valuation?
- Stock rises: growth, overbuying, slowness or error?
- Stock falls: sale, stockout, damage or cut-off?
- Margin too high: overvalued close or missing purchase?
- Negative margin: price, cost, return or incoherent data?
Since 3.0, BelloPOS Pro values stock at weighted average cost and keeps a real movement ledger — every entry carries a reason — then posts the variation entry and reconciles against the physical count. Which costs are includable, and any impairment, still need your accountant before the close.
Mistakes to avoid
- Using selling price.
- Switching average and FIFO without justification.
- Mixing case and unit.
- Missing returns.
- Calling every difference damage.
- Mixing quantity and impairment.
Frequently asked questions
What is the simple issued-cost formula?
For trading: opening stock + net purchases − closing stock, before other necessary adjustments.
Which CGNC methods are accepted?
Individual cost for identifiable goods; weighted average or FIFO for interchangeable goods.
Can LIFO be used in statements?
The CGNC says methods such as LIFO used in management require restatement for financial statements.
Does higher closing stock increase margin?
All else equal it reduces purchases consumed; if false or overvalued, margin is false too.
Does BelloPOS calculate the entry?
Since 3.0, Pro values at weighted average cost and posts the variation entry from the movement ledger. Includable costs, impairment and the close itself stay with your accountant.
What to take away
Reliable variation follows this order: observed quantity, explained movements, accepted cost, controlled current value, then entry. Margin is the process outcome, never its target.
Sources
The figures and rules quoted above come from these pages, read on the date given in the article.
Link every difference to a movement
Track receipts, sales, transfers, returns and losses by reference before closing valuation.
Read next
Other practical guides on the same subject: