What is replenishment in retail?

In retail, replenishment is how a retailer restocks its stores and distribution centres. A rule, such as a reorder point or a scheduled review against a forecast, sets the quantity, and a purchase order goes to the supplier. Each retailer sets its own process, including whether goods are delivered to a distribution centre or to stores.

What are the main types of replenishment?

The main approaches are a reorder point, where stock falling to a set level triggers an order; a scheduled review against a forecast; minimum and maximum stock levels; a pull signal such as a kanban; and vendor-managed inventory, where the supplier decides the order size. Most end in a purchase order; vendor-managed inventory differs.

What does a supplier receive from a retailer's replenishment system?

A purchase order, sent as an EDI message or by email, listing the products, quantities, delivery location and a due date set from the agreed lead time. Some retailers also share forecasts and stock data through a portal, by email or in standard messages. A forecast is a plan. The purchase order is the order.

← All articlesEDI

What is stock replenishment? How UK retailers reorder from suppliers

Stock replenishment explained from the UK supplier's side: the rules retailers use to decide what to reorder, how the purchase order reaches you, and the documents you send back.

Transalis9 November 2026

Replenishment looks different from each end. The retailer sees a stock level and a rule. The supplier sees an order with a due date. TechTarget's SearchERP defines replenishment as "the controlled and regular movement of inventory from an upstream point on the supply chain to a downstream location that requires sufficient stock to cover demand." When a retailer reorders from you, you are that upstream point, and the purchase order is how its decision reaches you.

Key takeaways

Stock replenishment is the controlled, regular movement of stock to the store or warehouse that needs it, so there is enough to cover demand.
In the UK retailer manuals quoted here, the retailer decides what to reorder and when with a rule, such as a reorder point, a scheduled review against a forecast or minimum and maximum levels. Under vendor-managed inventory, the supplier decides.
The retailer raises a purchase order, sent as an EDI message or by email, with a due date set from the lead time agreed with the supplier.
The supplier answers with an order response where the retailer asks for one, a despatch advice (ASN) before the goods arrive, and an invoice.
A forecast shared by a retailer is a plan, not an order: suppliers plan with the forecast and ship against the purchase order.

Short answer

Stock replenishment is the controlled, regular movement of stock to the store or warehouse that needs it, so there is enough to cover demand. In the UK retailer manuals quoted on this page, the retailer decides what to reorder and when, unless the supplier manages the stock under vendor-managed inventory. The retailer raises a purchase order, sent as an EDI message or by email, with a due date set from the lead time agreed with the supplier. The supplier answers with an order response where the retailer asks for one, a despatch advice (ASN) and an invoice.

How does stock replenishment work, from shelf to supplier and back?

In six steps. This is our summary from the supplier's side. Each retailer sets its own process, so the detail varies.

The retailer reads its sales and stock. Its replenishment rule works from these figures.
A rule sets the order. A reorder point or a scheduled review against a forecast are two examples.
The retailer raises a purchase order. It arrives as an EDI message or by email, and its due date comes from the lead time agreed with you.
You respond to the order. Where the retailer asks for one, an order response confirms the order or proposes changes.
You pick the order and send the despatch advice. The ASN goes before the goods arrive, so the retailer can prepare to receive them.
The retailer receives the delivery, and your invoice follows. The goods go to a distribution centre or a store, as the order says.

Steps 1 and 2 happen inside the retailer's systems, though some retailers share their sales, stock and forecast data with suppliers (see the section on forecasts and stock data below). From step 3, documents pass between the two businesses, and that is where EDI does its work.

How do retailers decide what to reorder and when?

With a replenishment rule. Here are five approaches, and what each one looks like from the supplier's side.

Method	What triggers the order	What the supplier sees
Reorder point	Stock falls to a set level, normally the forecast usage over the replenishment lead time plus safety stock	A purchase order when the level is reached
Scheduled review against a forecast	The retailer's system plans orders from its forecast on a regular cycle	A forecast or order plan first, then purchase orders
Minimum and maximum levels	Planned minimum and maximum stock levels for each product	Purchase orders; the levels themselves can travel in an inventory report (INVRPT)
Pull signal (kanban)	A signal that authorises withdrawal or production in a pull system	An order when the signal is raised
Vendor-managed inventory	The supplier, as decision-maker, sets the order size	The supplier makes the replenishment decision itself

The reorder point is the simplest to picture. Wikipedia describes it as "the level of inventory which triggers an action to replenish that particular inventory", and adds: "It is normally calculated as the forecast usage during the replenishment lead time plus safety stock." Where a retailer reorders this way, the lead time agreed with you is part of that calculation.

A scheduled review starts from a forecast. Marks & Spencer's ambient food logistics handbook (April 2019) says its forecast and ordering system "generates supplier orders, as well as a weekly forward forecast and order plan." For long-life ambient products and beers, wines and spirits, "M&S provides Suppliers with 16 week forecasts of expected demand, these are sent on a weekly basis via email." The supplier sees the plan first and the order later.

Minimum and maximum levels are stock levels that trading partners can exchange. GS1's EANCOM inventory report says its quantities "can indicate model or target stock, minimum stock, maximum stock and reordering point stock levels." The message carries the levels.

A pull signal works from use. The Lean Enterprise Institute's Lean Lexicon describes a kanban as a signalling device that authorises the production or withdrawal of items in a pull system. When the signal is raised, the order follows.

What is vendor-managed inventory?

Vendor-managed inventory (VMI) moves the reorder decision to the supplier. Under VMI, in Wikipedia's words, "the vendor is the decision-maker who determines the order size". The same entry notes that "there is no standard definition of VMI", and that usage varies between companies.

The UK retailer manuals quoted on this page describe a different split. The retailer shares a forecast and raises the purchase order itself.

How does a replenishment order reach the supplier?

As a purchase order. The Transalis purchase order guide puts it plainly: "A purchase order is the customer's instruction to supply: which products, how many, where to deliver and when, under the customer's own PO number."

The channel is the retailer's choice. M&S's ambient handbook says "Finalised Purchase Orders (POs) are transmitted to suppliers via EDI", while the Wickes supplier manual (January 2022) says "The Purchase Order (PO) will then be raised by either EDI or email." On your side, the channel changes the work: "An EDI order arrives as data your systems can read, while an emailed PDF order has to be opened, read and keyed in by hand."

In EDI, the order's name depends on the standard: an EANCOM message (ORDERS), a TRADACOMS file (Order File) or an X12 transaction set (850). In its EANCOM guidance, GS1 recommends one order per delivery: "The recommended business practice is that one Purchase Order is placed for one delivery in one location at one time." A standing agreement can work differently, through "blanket orders followed at a later date by a series of call-offs".

The delivery point can change the rules. The Wickes manual has separate sections for delivering to its distribution centres and to its stores, each with its own booking process and delivery performance measures.

Once the order is inside your business, it becomes your sales order. As that guide explains, "GS1's EANCOM standard has no sales order message: the customer's ORDERS message becomes the sales order once it is inside the supplier's system." From there, the pick and despatch run in your own systems, such as an ERP and a warehouse management system.

What does the supplier send back?

An order response where asked, then a despatch advice and an invoice. The retail EDI requirements guide covers which documents a UK retailer asks for once you win the contract.

The order response. On a replenishment order, it can tell the retailer early that a line will arrive short or not at all. Not every retailer asks for one, and your customer's spec sets the rule. GS1's order response message (ORDRSP) can be "an acknowledgement of receipt and understanding of data content of the Purchase Order, a confirmation of acceptance of the Purchase Order, a proposal of amendment to the Purchase Order, a notification of non-acceptance for all or part of the Purchase Order."

The despatch advice (ASN). The Transalis ASN guide defines it: "An Advance Shipping Notice (ASN) is an EDI message sent when goods leave the supplier, listing what is coming, how it is packed and when it will arrive." GS1 is firm on timing: "The Despatch Advice message should always be sent before goods are physically delivered or returned."

The invoice. GS1 links it to the despatch advice: one purpose of the despatch advice is to "enable the control between despatched goods with the following invoice."

Some retailers also send a receiving advice back, saying what arrived and what was accepted against the order.

How do forecasts and stock data reach suppliers?

Alongside the orders. GS1 groups its standard messages for this data as reporting and planning messages, "used to supply the trading partner with relevant information or future requirements."

Delivery schedule (DELFOR). From buyer to supplier, for "short term delivery instructions and/or medium to long term product/service forecast for planning purposes".
Sales data report (SLSRPT) and sales forecast (SLSFCT). Sales, or forecast sales, by location, period, product, price and quantity. GS1 sets a limit on both: "the message should never be used to replace business transactions such as Purchase Orders, Delivery Schedules or Inventory Reports."
Inventory report (INVRPT). Stock held, and planned or target stock levels.

The Transalis guide to EDI transactions lists the delivery schedule, the inventory report and the sales data report, with what each does and its EANCOM and X12 names. It marks the TRADACOMS name for all three as not confirmed.

Some retailers share this data through a portal or by email instead. The Wickes manual describes i-Supply, its supplier system, as "a one stop shop for our suppliers to access data", covering sales, current stock by product and location, and a demand forecast. Ocado's supplier manual (September 2024) lists its portal as the place where suppliers "Review delivery forecasts and order schedules" and "Give Ocado advance warning of PO shortages".

A forecast is a plan. The Travis Perkins supplier manual (October 2021) is explicit about its own: "we give our forecasts in good faith, but without any liability or obligation on the part of the Travis Perkins Group or any of our businesses." Plan with the forecast. Ship against the order.

The data can also run the other way. NHS Supply Chain, a UK public-sector buyer, says in its operational supplier requirements (version 4.1, 2025): "Inbound profiles are set up on our systems based on demand history supplied by the awarded supplier."

Where do lead time and OTIF fit?

Lead time sets when a replenishment order is due. OTIF records whether it arrived on time and in full.

The Transalis lead time guide defines it: "Lead time is the time from receiving a customer's order to delivering the goods." It also explains who holds it: "The supplier supplies or agrees its lead time, and the buyer holds it on its own system and puts a due date on each order from it." Travis Perkins's on-time measure works this way: "The expected due date is generated from our agreed lead times held in POS". M&S gives a reason to keep lead times short: "Shorter lead times aid agile forecasting and support greater customer availability."

The OTIF guide defines the score: "OTIF, short for on time in full, is the share of a customer's orders delivered on the due date or inside the booked slot and in the quantity ordered." The due date you are measured against starts with the lead time you agreed.

How Transalis connects suppliers to retailers' orders

In the retailer manuals quoted here, the replenishment rule belongs to your customer; vendor-managed inventory is the exception. The order traffic that follows it is where Transalis works. Transalis is a managed outcomes provider for B2B integration, EDI and eInvoicing, and its EDI page describes three ways in:

Web EDI: "A managed web portal to receive orders, send invoices and manage compliance in a browser."
Integrated EDI: "EDI wired directly into your ERP, accounting or warehouse system."
Enterprise EDI: "A scalable, enterprise-grade platform for high transaction volumes across thousands of trading partners, countries and systems."

The web EDI guide draws the line between the first two: "With web EDI a person reads each order and keys each invoice, while integrated EDI connects an ERP, accounting or warehouse system so documents flow without rekeying."

Transalis also sends order responses and receiving advice messages for its customers.

Book a 30-minute call with a Transalis retail supply chain specialist to walk through EDI between your systems and your retail customers.

Frequently asked questions

What is stock replenishment?: Stock replenishment is the controlled, regular movement of stock to the store or warehouse that needs it, so there is enough to cover demand. In the UK retailer manuals quoted here, the retailer decides what to reorder and when and raises a purchase order. Under vendor-managed inventory, the supplier decides.
What is replenishment in retail?: In retail, replenishment is how a retailer restocks its stores and distribution centres. A rule, such as a reorder point or a scheduled review against a forecast, sets the quantity, and a purchase order goes to the supplier. Each retailer sets its own process, including whether goods are delivered to a distribution centre or to stores.
What are the main types of replenishment?: The main approaches are a reorder point, where stock falling to a set level triggers an order; a scheduled review against a forecast; minimum and maximum stock levels; a pull signal such as a kanban; and vendor-managed inventory, where the supplier decides the order size. Most end in a purchase order; vendor-managed inventory differs.
What is a reorder point?: A reorder point is the stock level that triggers a replenishment order. Wikipedia says it is normally calculated as the forecast usage during the replenishment lead time plus safety stock. Where a retailer reorders this way, the lead time agreed with the supplier is part of that calculation, alongside the forecast usage and the safety stock.
What does a supplier receive from a retailer's replenishment system?: A purchase order, sent as an EDI message or by email, listing the products, quantities, delivery location and a due date set from the agreed lead time. Some retailers also share forecasts and stock data through a portal, by email or in standard messages. A forecast is a plan. The purchase order is the order.
What is vendor-managed inventory?: Vendor-managed inventory (VMI) moves the reorder decision from the retailer to the supplier. Wikipedia describes the vendor as the decision-maker who determines the order size, and notes there is no standard definition of VMI, so usage varies between companies. A retailer raising its own orders against a shared forecast is a different model.

Want this working in your business?

We will look at how you trade today, and show you what moving to Transalis involves, while your business keeps trading.