Stock Reservation: Don't Sell What's Already Promised
Short answer: Stock reservation locks available inventory against a confirmed order so the same unit can't be promised to a second customer. Without it, your available quantity and your sellable quantity are the same number — which is wrong the moment the first order is confirmed but not yet shipped.
The Problem with "Available Stock"
Most basic inventory systems show one number: on-hand quantity. If you have 50 units on hand and no orders in progress, that's correct. The moment you have 10 units committed to a confirmed order awaiting packing, your true available-to-promise quantity is 40 — not 50.
If your sales team or marketplace listings still show 50, the next order for 45 units appears to go through cleanly. Then two fulfilment jobs compete for the same stock.
For trading companies handling multiple customers and channels, this isn't an edge case. It happens weekly at moderate order volumes.
How Stock Reservation Works
A reservation system adds a committed layer to stock tracking:
| Stock Category | Description |
|---|---|
| On-hand | Physical units in the warehouse |
| Reserved | Committed to confirmed orders, not yet shipped |
| Available to Promise | On-hand minus reserved |
| On order | Expected inbound stock from suppliers |
| Projected available | Available to promise plus on order |
Sales and marketplace systems should quote from available-to-promise, not on-hand. The reservation is created when a sales order is confirmed and released when the delivery order is dispatched.
Where Reservations Break Down
Reservation logic sounds simple — and it is, when implemented properly. The breakdowns come from gaps in the process:
Manual sales orders that bypass the system. A phone order noted on paper doesn't create a reservation. The item gets picked for that order, but the system doesn't know it was committed until stock vanishes.
Marketplace oversell. Shopee and Lazada accept orders independently of your ERP. Unless your inventory warehouse system pushes live available-to-promise quantities to the marketplace platforms and updates them in near real-time, the platforms sell from on-hand.
Partial shipments. An order for 20 units shipped as 15 first and 5 later needs the reservation to partially release. Systems that only do full-release create phantom reservations that block stock that's actually available.
Reservation in Multi-Location Warehouses
When stock is spread across multiple locations or bins, reservation needs to specify where the committed stock sits — not just that it's committed. This matters for pick routing: a reservation against a location that's being replenished creates a fulfilment hold that a simple quantity check wouldn't catch.
What a Proper Implementation Looks Like
A stock reservation module connects to:
- Sales order confirmation (creates reservation)
- Inventory movement (validates reservation against physical location)
- Dispatch / delivery order creation (releases reservation)
- Returns (restores available stock on acceptance)
The whole loop needs to be automated. Manual reservation management — spreadsheets, manual stock holds — fails at the exact moment it's most needed: when volume spikes and the warehouse is busy.
FAQ
Can AutoCount handle stock reservations natively?
AutoCount tracks committed quantities through sales orders and delivery orders in its standard flow. For more granular control — by warehouse location, by channel, with real-time updates to marketplace listings — custom integration is usually required.
What's the difference between a reservation and a stock hold?
A reservation is tied to a specific sales order and is released automatically when that order ships or cancels. A stock hold is a manual block — useful for quality holds or reserved-for-promotion stock — and requires manual release. Both are needed; they serve different purposes.
How does stock reservation interact with backorders?
A reservation can't be created for stock that doesn't exist. Backorder logic allows an order to be accepted when stock will arrive — based on projected available quantity from open purchase orders. These are separate features that need to work together.
Book a System Audit