Inventory Due Diligence in Manufacturing: Quality, Obsolescence and Working Capital

Inventory due diligence in manufacturing must establish more than the ledger balance. Investors need to know whether stock exists, belongs to the target, meets specification, can be converted or sold, and is required at the level assumed in the deal. Weak inventory can overstate working capital, hide margin leakage and consume cash after closing. The analysis should connect physical and commercial evidence to reserves, sustainable earnings, the working-capital peg and integration actions.

Map every inventory population

Start with the trial balance, inventory subledger, stock-location list and accounting policies. Reconcile raw materials, packaging, consumables, work-in-progress, finished goods, maintenance spares, scrap and goods in transit. Identify stock at subcontractors, third-party warehouses, consignment locations and customer premises. Separately flag customer-owned materials and tooling that are physically present but not owned by the target.

The perimeter matters. A clean count at the main warehouse can miss high-risk WIP on the floor, slow-moving stock at remote sites or unrecorded scrap. Reconcile quantities and values by entity and location, including blocked, quarantine and quality-hold codes.

Observe the count and test cut-off

A well-designed observation tests management's count process rather than replacing it. Review instructions, segregation, tag control, unit-of-measure conversions and treatment of moving goods. Select samples from records to floor for existence and from floor to records for completeness. Include high-value items, random items, zero or negative balances, sealed containers and similar-looking grades.

Capture condition as well as quantity: rust, moisture, damaged packaging, mixed lots, expired shelf life, poor identification or uncontrolled storage can affect usability. Investigate repeated recounts and unexplained adjustments.

Test cut-off using dispatch, goods-receipt and production records immediately before and after the count or reporting date. Goods in transit require shipping terms and title evidence. For subcontracted inventory, obtain third-party confirmation where appropriate and reconcile material sent, processed, returned, consumed and scrapped.

Challenge ownership and availability

Inspect purchase documents, supplier terms, consignment agreements, customer contracts, warehouse receipts and financing arrangements. Stock may be physically controlled but subject to retention of title, lender security, customs restrictions or customer ownership. Legal advisers should determine rights, encumbrances and transferability for the transaction.

Also ask whether inventory is genuinely available for ordinary use. Quality holds, regulatory release, customer-specific approvals, export restrictions and unresolved inspection can turn book stock into unavailable cash. Reserved production stock may be necessary for an order but unusable elsewhere if that order is cancelled.

Test WIP stage and conversion cost

Work-in-progress is particularly judgemental. Trace selected batches through route cards, machine or labour records, material issues, quality status and subsequent completion. Confirm the percentage of completion with physical and process evidence, not a broad month-end convention. A batch waiting for a scarce process, failed test or customer approval may need more cost and time than the system suggests.

Review standard cost components and overhead absorption. Under-utilisation can create variances or inappropriate absorption depending on the accounting framework. Determine whether rework, abnormal scrap and idle costs are treated consistently. Accounting specialists should assess compliance with the reporting framework; diligence should focus on the economic cash and margin implications.

Analyse ageing by risk, not one calendar rule

A simple no-movement report is useful but incomplete. Some strategic spares move rarely and remain essential; fast-moving material can still be obsolete after an engineering change. Segment stock by:

• last receipt, issue, production and sale dates;
• shelf life, batch and storage requirement;
• current bill-of-material usage and approved-product status;
• customer, platform or drawing dependency;
• open orders, forecast demand and minimum order quantities;
• subsequent consumption, sale, return or disposal.

Interview engineering, quality, sales, procurement and maintenance—not only finance. Review product discontinuations, specification changes, customer exits, alternative materials and excess purchases made to secure discounts or manage shortages.

Test net realisable value and disposal assumptions

For finished goods, compare cost with expected selling price less the costs needed to complete and sell, applying the relevant accounting framework. Challenge expected prices using recent invoices, post-period sales, returns and customer-specific concessions. For raw material and WIP, consider whether the finished product is profitable and whether conversion is technically and commercially feasible.

Scrap quotations should reflect grade, contamination, handling and disposal cost. Hazardous or regulated material may create a disposal liability rather than recovery. Tax, environmental and accounting advisers should review transaction-specific treatment.

Do not assume the recorded reserve captures all economic risk. Management's policy may use broad ageing bands, exclude WIP or rely on an optimistic demand forecast. Conversely, a fully reserved critical spare can have substantial operating utility. Prepare an item-level or risk-bucket bridge between book provision and diligence estimate.

Connect inventory to earnings and cash

Inventory findings can reveal operating issues beyond the balance sheet. Excess finished goods may indicate channel weakness; rising WIP may signal a bottleneck; raw-material variance may indicate yield loss; spare shortages may increase downtime. Reconcile inventory movements with production, cost of sales, purchase volumes, gross margin and cash flow.

For the working-capital mechanism, agree definitions carefully. Address provisions, write-offs, consignment stock, goods in transit, customer advances and intercompany items consistently with the locked-box or completion-accounts structure. Analyse normal inventory by month, season, product mix and service strategy rather than selecting an arbitrary average.

A buyer should not pay for unusable stock through working capital and then fund its disposal after closing. Depending on evidence and legal advice, responses may include specific reserves, excluded items, a tailored peg, seller disposal, indemnity or escrow. Avoid double counting the same item in enterprise-value adjustments and completion accounts.

Make the findings operational

Post-close actions may include quarantine discipline, cycle counting, master-data clean-up, engineering disposition, supplier returns, liquidation controls and revised planning parameters. Assign accountable owners and protect customer service while inventory is reduced. The due diligence and business advisory services page provides related context.

Conclusion

Reliable inventory diligence follows stock from physical existence to economic use. It proves quantity and rights, tests quality and conversion, challenges demand and then reflects the result once—and only once—in earnings, working capital, liabilities and the deal.