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MarginLab Insights
Insight 05 · Inventory and liquidity
The working-capital signal

How Inventory Growth Can Quietly Destroy Cash Flow

Inventory growth can absorb cash without appearing as an equivalent expense in the current profit result. A growing store may be earning money on what it sells while spending even more on what it has not sold.

The business question

How much of the reported profit remains available after the next inventory commitment?

Economic signal€66,000 profit; €54,000 cash consumption
Illustrative analysis
01
Opening inventory€60,000 at cost
02
Closing inventory€180,000 after three months
03
Cumulative operating profit€66,000
04
Opening cash€50,000 becomes a €4,000 funding gap
Decision implicationReconcile profit to inventory cash requirements before increasing purchase orders.
SeriesMarginLab Insights
FocusInventory and liquidity
EvidenceConstructed scenarios
PreparedSeptember 2026
Methodology: All figures are illustrative, not customer results or empirical benchmarks. Amounts exclude VAT/sales tax. The illustration assumes cash collection and payment within each month, no change in payables or receivables, and no depreciation, tax, debt, capital expenditure or owner distributions.
01 · Accounting versus cash

Purchasing inventory and consuming it are different events.

Product cost enters the modeled profit result as the units are sold. The cash payment may happen earlier. The difference accumulates on the balance sheet as unsold stock.

Inventory movement at costClosing inventory = opening inventory + purchases − COGS

This model has no write-downs, losses or other inventory adjustments.

IAS 2 describes recognition of inventory cost as an expense when the related inventory is sold and addresses write-downs where necessary. See the IFRS inventory standard summary. The scenario below isolates purchase timing rather than prescribing accounting treatment for a particular merchant.

02 · Evidence

Three profitable months consume the opening cash buffer.

Purchases grow faster than the cost of inventory sold. Each month reports a stronger profit while an even larger amount is tied up in inventory.

Three-month inventory and cash bridge; euros
MeasureMonth 1Month 2Month 3
Opening inventory60,00090,000130,000
Purchases paid70,00085,000100,000
COGS already in profit(40,000)(45,000)(50,000)
Closing inventory90,000130,000180,000
Inventory increase30,00040,00050,000
Operating profit20,00022,00024,000
Cash change: profit less inventory increase(10,000)(18,000)(26,000)
Closing cash / funding gap40,00022,000(4,000)
The negative closing balance is a funding requirement, not an assumption that the store can spend unavailable cash. The operating plan needs financing, smaller purchases or another cash source before that point.
03 · Mechanism

Do not subtract the entire purchase order from profit.

Profit already includes €135,000 of COGS over the three months. Deducting all €255,000 of purchases from profit would count the sold inventory cost twice.

Cumulative cash reconciliation€66,000 profit − €120,000 inventory increase = −€54,000

Opening cash €50,000 − €54,000 = a €4,000 funding requirement.

Finding 1

Expense recognition

The €135,000 cost of sold products is already reflected in the €66,000 profit total.

Finding 2

Additional cash commitment

Purchases exceed that recognized cost by €120,000. This is the incremental inventory investment consuming cash.

04 · Diagnostic pattern

Inventory quality determines whether the cash comes back.

A larger stock balance can reflect useful safety stock, a supplier minimum or slow-moving variants. These have different recovery prospects even if their accounting cost is identical.

Finding 1

Demand-backed stock

Units tied to credible near-term demand may turn back into cash quickly. Compare coverage with replenishment lead time and variability.

Finding 2

Assortment fragmentation

Many individually small variant positions can tie up substantial cash. Aggregate growth can hide sizes or colors with little sell-through.

Finding 3

Aging exposure

Old stock may require markdowns or incur storage charges. Cost on the balance sheet is not a guarantee of recoverable cash.

Do not impose a single inventory-days threshold across all SKUs. A long-lead seasonal item and a locally replenished evergreen product have different operating requirements.

05 · Decision model

Purchase capacity should be derived from liquidity.

In Month 3, opening cash is €22,000 and operating profit is €24,000. To preserve a €20,000 closing cash buffer under the stated assumptions, inventory may increase by at most €26,000.

Cash-constrained Month 3 purchases€50,000 COGS + €26,000 inventory increase = €76,000 purchases

Reducing the planned €100,000 purchase by €24,000 lifts the modeled closing cash from −€4,000 to €20,000.

This is a funding limit, not proof that €76,000 of inventory supports demand. The purchasing team must test service levels and supplier commitments before applying the cap.

06 · Investigation

Map each cash commitment to a replenishment reason.

The useful question is not whether inventory is increasing. It is whether the increase is justified by demand, service protection or purchasing economics and whether the cash plan can support it.

  1. Build a dated cash calendar

    Include deposits, balances, freight, settlement dates and existing purchase commitments. A monthly total can conceal an earlier weekly shortfall.

  2. Separate stock requirements

    Distinguish base demand, safety stock, minimum-order excess and speculative buying. Identify which component is negotiable.

  3. Stress-test sell-through

    Model slower unit sales and longer holding periods. A margin-preserving purchase can still create an unacceptable liquidity gap.

  4. Revisit supplier terms

    Staged deliveries or payment timing can reduce peak funding needs. They do not eliminate the risk of unsellable inventory.

07 · Monitoring

Monitor purchases against consumption and available cash.

A rolling cash forecast should sit beside the profit report. Inventory increases belong in both the operational plan and the financing discussion.

Signals worth investigating together
SignalEconomic question
Purchases persistently exceed COGSIs the extra stock tied to credible demand?
Inventory rises faster than salesAre coverage and variant fragmentation increasing?
Positive profit; falling cashWhich working-capital balances explain the difference?
Supplier discount requires a larger orderDo savings exceed holding, markdown and liquidity costs?

Use the inventory profitability framework to connect assortment economics with the stock balance. Review commitments already placed as well as units physically in the warehouse.

Decision implication

Profitability does not fund unlimited inventory growth.

The store earns €66,000 in the illustration, but a €120,000 inventory expansion consumes all of that profit and €54,000 of cash. The problem becomes visible early when purchases, COGS and cash are reconciled.

PI
The operating rule

Approve inventory growth only when its demand rationale and dated funding plan are both credible.

Continue the analysis

Translate the profit plan into a cash plan

Model inventory investment and other working-capital movements alongside operating cash generation.

Decision checkpointWhich purchase commitment creates the first cash shortfall?

Find the date before negotiating the remedy. A profitable quarter can still contain a week the business cannot fund.

Evidence standardIllustrative economics · explicit assumptions