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Average inventory

Average inventory represents the typical quantity or value held over a period on the chosen calculation basis. In a simple constant-demand, instantaneous-replenishment model, average cycle stock is half the order quantity; add buffer stock where maintained. Averaging opening and closing balances is a different approximation and can be misleading with seasonal movements. Match the measure to the purpose, such as holding-cost calculation or a financial ratio.

Worked example

Order size 1,000 and constant buffer 200 give model average inventory 500 + 200 = 700 units.

Common mistake

Do not use Q/2 blindly when inventory is gradually replenished, demand is irregular or the model’s assumptions do not hold.

Where it appears in your exams

QualificationExamRelationshipPeriod
ACCA MA Direct September 2026–June 2027
FIA FMA Direct September 2026–June 2027