VMI vs Consignment Inventory: Key Differences, Ownership, Replenishment & Examples

Vendor-Managed Inventory (VMI) and consignment inventory are often discussed together, but they solve different supply-chain questions. VMI is mainly about who manages replenishment, while consignment is mainly about who owns the inventory. They can exist separately or be combined.

VMI vs Consignment Inventory at a Glance

What Is Vendor-Managed Inventory?

In a VMI arrangement, the supplier receives agreed inventory and demand information from the customer and takes responsibility for planning replenishment within defined rules. Instead of waiting for a traditional purchase order each time stock falls, the supplier monitors agreed signals such as on-hand quantity, demand, forecasts, minimum/maximum levels or days of supply.

SAP describes VMI as a collaborative replenishment process in which the vendor uses customer inventory and demand information to determine replenishment requirements. Importantly, SAP supports both consigned and non-consigned VMI. This is why VMI should not automatically be treated as a stock-ownership model.

Typical VMI Flow

1. Buyer and supplier agree which items are included.
2. Buyer shares inventory, consumption and/or forecast information.
3. Target stock, minimum/maximum levels, service expectations and lead-time rules are agreed.
4. Supplier calculates replenishment requirements.
5. Supplier creates or proposes replenishment shipments.
6. Both parties monitor service, stock and exceptions.

What Is Consignment Inventory?

Under a consignment arrangement, goods are physically located at the customer’s site but remain owned by the supplier until an agreed ownership event occurs — commonly withdrawal or consumption. SAP’s current S/4HANA documentation describes vendor consignment in exactly this way: the supplier remains the legal owner until material is withdrawn from consignment stock, at which point a liability arises.

Consignment therefore focuses primarily on ownership, valuation and payment timing. It does not automatically mean the supplier is responsible for replenishment planning.

Why the Two Models Are Commonly Confused

The models are often deployed together. A supplier may own stock sitting at the customer site and manage replenishment. This is consigned VMI. In another VMI arrangement, the buyer may take ownership at receipt while the supplier still determines replenishment. That is non-consigned VMI.

A useful professional rule is:

• VMI = replenishment responsibility.
• Consignment = ownership timing.

Practical Example: MRO Spare Parts

Assume a manufacturing plant consumes bearings regularly. The supplier holds 150 bearings inside the customer’s storeroom. The agreed minimum is 50 and maximum is 150.

If the supplier receives daily stock balances and automatically replenishes the location when the quantity falls toward the minimum, that is VMI. If the bearings remain the supplier’s property until the plant issues them to maintenance, that is consignment. If both conditions apply, it is consigned VMI.

Commercial and Contract Controls

A VMI or consignment programme should not rely on informal assumptions. Agreements should clarify:

• Which SKUs and locations are included.
• When legal title and risk transfer.
• Replenishment rules, minimum/maximum levels and service targets.
• Forecast and data-sharing frequency.
• Lead times and emergency replenishment.
• How consumption is recorded and reconciled.
• Who bears loss, damage, obsolescence and shrinkage risk.
• Stock-count frequency and discrepancy treatment.
• Pricing and invoicing trigger.
• Returns, slow-moving stock and programme termination.

Useful KPIs

• Stock availability / service level
• Stockout rate
• Inventory turns
• Days of supply
• Forecast accuracy where forecasts drive replenishment
• Supplier replenishment adherence
• Emergency order frequency
• Excess and obsolete inventory
• Inventory-record accuracy
• Consignment reconciliation differences

When VMI Works Best

VMI is strongest where demand is reasonably repeatable, data is reliable, the supplier has sufficient planning capability, and both parties are willing to share information. SAP notes that VMI is particularly suited to repeatedly requested standardized products and situations where the supplier benefits from better visibility of actual customer requirements.

When Consignment Works Best

Consignment can be useful for high-value spares, uncertain consumption, critical materials or items where immediate local availability is important but the buyer wants to defer ownership until use. The model should still be assessed against supplier financing cost, accounting treatment, shelf life, obsolescence and physical control requirements.

VMI vs Consignment: Which Should You Choose?

Choose based on the problem you are trying to solve. If replenishment workload and availability are the main issues, evaluate VMI. If buyer cash tied up in stock is the main issue, evaluate consignment. If both problems matter and the supplier has the capability to manage stock, a consigned VMI arrangement may be appropriate.

Common Interview Question

Question: What is the difference between VMI and consignment inventory?

Strong answer: VMI determines who manages replenishment; consignment determines when ownership transfers. A VMI programme may be consigned or non-consigned, and consignment stock does not necessarily have to be vendor managed.

Related SCMANA Guides

• Cycle Stock vs Safety Stock
• ABC, VED and Pareto Inventory Classification
• Vendor-Managed Inventory in Practice

References

• SAP — Supplier-Managed Inventory
• SAP — Consignment

Accounting, tax and legal treatment can vary by jurisdiction and contract. Confirm the commercial and accounting treatment appropriate to your organisation.