Buying Twice the Inventory for a 10% Supplier Discount
The supplier offers a €2 unit saving if the merchant doubles its order. The discount is attractive on the purchase invoice, but it commits €16,000 more cash immediately and doubles initial stock coverage.
Will the additional inventory earn back its purchase, holding and risk costs before the cash is needed elsewhere?
A unit saving does not mean a smaller cash outflow.
At 250 units of demand per month, the normal 1,000-unit purchase lasts four months. If demand persists, the merchant can buy another 1,000 units at Month 4. The bulk offer buys both tranches immediately.
| Measure | Staged purchase | Bulk offer |
|---|---|---|
| Initial units | 1,000 | 2,000 |
| Initial unit cost | €20 | €18 |
| Initial cash payment | €20,000 | €36,000 |
| Month 4 replenishment | 1,000 units / €20,000 | None |
| Total units bought | 2,000 | 2,000 |
| Total purchase cost | €40,000 | €36,000 |
The comparison assumes the normal €20 price remains available, replenishment arrives when needed and demand is sufficient for 2,000 units. The staged option preserves the ability to reconsider the second purchase.
The €4,000 purchase saving is not the final benefit.
During the first four months, the bulk option carries 1,000 extra units compared with staged buying. At €0.20 storage per additional unit per month, the incremental storage cost is €800.
After the staged replenishment at Month 4, remaining quantities match under the full-demand scenario.
This simple benchmark prices the extra cash commitment until the staged payment date. It is not an additional accounting expense unless a real financing charge is incurred.
The €4,000 saving therefore becomes €3,200 after explicit storage, or €2,560 after the stated capital opportunity cost. Do not deduct both this benchmark and an actual financing charge for the same funding cost.
The offer works if normal demand and timing hold.
Assume each normally sold unit produces €40 of net receipts after all non-inventory variable selling costs. This could be a €50 realized price less €10 of selling and fulfillment burden.
| Measure | Staged | Bulk |
|---|---|---|
| Net receipts before inventory cost | €80,000 | €80,000 |
| Inventory purchase cost | (€40,000) | (€36,000) |
| Incremental storage versus staged | €0 | (€800) |
| Contribution on comparison basis | €40,000 | €43,200 |
| Capital opportunity cost | €0 | (€640) |
| Economic result after capital benchmark | €40,000 | €42,560 |
The option to avoid the second purchase has value.
Now assume only 1,000 units sell normally over eight months. The staged buyer does not reorder. The bulk buyer clears its 1,000 surplus units at €10 net receipts each after all clearance selling costs.
| Measure | Staged | Bulk |
|---|---|---|
| Normal-sale net receipts: 1,000 × €40 | 40,000 | 40,000 |
| Surplus clearance net receipts | 0 | 10,000 |
| Initial inventory cost | (20,000) | (36,000) |
| Incremental storage: 1,000 × 8 × €0.20 | 0 | (1,600) |
| Contribution on comparison basis | 20,000 | 12,400 |
| Capital benchmark: €16,000 × 12% × 8/12 | 0 | (1,280) |
| Economic result | 20,000 | 11,120 |
The bulk offer is €8,880 worse after storage and the capital benchmark. The clearance value replaces normal-price proceeds; it is not an additional markdown expense deducted from those proceeds a second time.
The surplus must recover more than €18 per unit.
In the slow-demand scenario, the bulk purchase requires €16,000 more upfront than the staged purchase, plus €1,600 storage and €1,280 of modeled capital cost.
At €10 net clearance receipts, the surplus falls €8.88 per unit short. If it becomes dead stock with no recovery, the economic disadvantage is €18,880.
A positive expected economic result does not remove the liquidity constraint. Financing changes the cash plan and may change the economic result; it must be modeled explicitly.
Accept the discount only when both gates clear.
The full-demand illustration favors the offer by €2,560. The slow-demand illustration reverses the decision. The merchant needs evidence about sell-through and a funded purchase calendar, not just a better unit cost.
- Validate demand by SKU and variant
Use actual depletion and committed demand. Do not infer eight months of sell-through from a short promotional spike.
- Price the downside
Estimate net clearance recovery, storage duration and the chance of unsellable stock. Keep disposal and selling costs inside the net recovery assumption.
- Verify the replenishment alternative
Confirm supplier lead times, future price and availability. A staged comparison is only credible if the second order can actually arrive when needed.
- Check cash before signing
Include existing commitments and minimum liquidity. Negotiate terms or quantity if the initial payment breaches the operating reserve.
The stock planning framework and inventory turnover calculator help connect purchase quantity to expected depletion. They do not replace SKU-level demand evidence.
The 10% discount is worth €2,560 only in the favorable demand case.
With full normal-price sell-through, savings exceed incremental storage and the stated capital benchmark. With only half the units sold normally and €10 net clearance recovery, the same offer is €8,880 worse than staged buying.
A cheaper unit can create a more expensive decision.
The offer saves €4,000 on 2,000 units but commits €16,000 more cash at the start.
Slow-demand surplus needs €18.88 net recovery per unit.
That hurdle includes incremental storage and the capital benchmark. The assumed €10 clearance recovery does not clear it.
Connect the purchase order to working capital
Model the initial commitment and inventory holding period before treating supplier savings as available profit.