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    Cost Structure Analysis · Interview Question

    A manufacturing company's COGS increased from 55% to 65% of revenue over 3 years. What are the likely drivers?

    How to answer

    A 10pp increase in COGS/revenue is massive. Investigate: (1) Input cost inflation — raw materials, energy, or labor costs rose (check commodity indices), (2) Volume decline — if revenue dropped, fixed manufacturing overhead is spread over fewer units, raising per-unit COGS, (3) Product mix shift — selling more low-margin products, (4) Supply chain disruption — emergency sourcing, expedited shipping, (5) Manufacturing inefficiency — lower yields, higher scrap rates, (6) Pricing pressure — revenue denominator shrank due to discounting while costs held steady. Quantify each: e.g., if raw materials are 40% of COGS and rose 15%, that explains 6pp of the 10pp increase.

    Key idea: Decompose COGS into components and check what drove each one

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