When the Supplier Owns the Shelf: A VMI Story Worth Learning From
A regional building-products distributor we will call Northline came out of the worst of the 2020 disruptions tired of stockouts. Two SKUs that contractors bought every week kept hitting zero while three slow movers tied up cash. Early in 2021, with freight still unreliable and the buying team stretched thin by remote work, Northline decided to try vendor-managed inventory (VMI) with its largest fastener supplier. The idea was simple: let the supplier watch the shelves and replenish them. The execution was anything but simple, and the lessons are worth borrowing.
VMI is an arrangement where the supplier, not the buyer, decides when and how much to ship, using shared data on stock levels and demand. Done well, it cuts stockouts and reduces the buyer's planning burden. Done carelessly, it transfers control to a party whose incentives are not perfectly aligned with yours. Northline learned both halves of that sentence.
What went right early
The first ninety days looked like a success. The supplier had a wider view of demand across many customers, so it forecast Northline's fast movers better than Northline's own spreadsheet ever had. Replenishment became steady. The buying team stopped firefighting and spent its time on sourcing harder-to-find materials. On paper, service levels on the covered SKUs rose from the low 80s to the high 90s within a quarter.
Shared, near-real-time stock data removed the guesswork from reorder timing.
The supplier absorbed the forecasting work, freeing scarce buyer capacity during a stretched, hybrid-work period.
Smaller, more frequent shipments smoothed the warehouse's receiving workload.
Where it nearly broke
The trouble started when a backorder hit the supplier's plant. Because the contract set a target stock level but no penalty for missing it, the supplier quietly prioritised its larger accounts. Northline's shelves drifted down, and nobody on Northline's side noticed quickly because they had stopped watching those SKUs. The arrangement had removed the work but also removed the visibility. A second problem surfaced at quarter end: the supplier pushed extra stock to hit its own sales targets, and Northline's carrying cost crept up on items it did not need yet.
The fixes that saved it
Write the service level into the contract. Northline added a measurable fill-rate target with a review trigger, so a missed level prompted a conversation instead of silence.
Keep a dashboard the buyer still reads. Handing off the work does not mean handing off attention. A weekly exception report flagged any SKU trending toward zero.
Cap the inventory the supplier can push. Maximum stock levels and an agreed reorder logic stopped quarter-end dumping.
Agree on who owns the data and the demand signal. Both sides worked from the same point-of-sale and on-hand feed, refreshed daily, so neither could claim a different picture.
Pilot on a narrow slice first. Starting with one supplier and a dozen SKUs made the failures cheap and the lessons clear before scaling.
The deeper lesson is that VMI is a partnership, not a hand-off. It works when both parties share accurate data, when the contract aligns incentives, and when the buyer keeps enough oversight to catch drift early. In a recovery period where demand was still jumpy and supply still fragile, the discipline of clear terms mattered more than the technology. Northline kept VMI, but it kept its eyes open too.
If you are weighing a VMI arrangement or want supplier contracts that align incentives and protect service levels, XNM's procurement, sourcing & contract management can help you structure it so the partnership holds up under pressure.