One Stock Pool, More Than Amazon: How Sellers Can Use German Inventory Across FBA, FBM and B2B

A seller has 3,000 units of one SKU in a German warehouse. Amazon is showing about three weeks of cover at the fulfilment centres. The seller’s webshop takes a steady run of orders. A retail buyer has asked for 600 units on pallets by the end of the month.

Every one of those demands can be met from the same stock. None of them can be met from the same unit twice.

Holding inventory in Germany outside Amazon gives a seller several ways to sell it: FBA replenishment, merchant-fulfilled (FBM) orders on Amazon, orders from a webshop or other marketplaces, and B2B dispatch. But one physical stock pool is not one fulfilment workflow. Each route pulls on the same units with different timing, different packaging and different consequences when the count is wrong.

One warehouse address does not mean one stock position

“We have 3,000 units in Germany” describes a location. It isn’t yet an inventory plan.

In a working warehouse those units sit in several states at once. Some are received and put away. Some are labelled and boxed for an FBA shipment that hasn’t been collected. Some are allocated to open orders but not yet picked. Some are in returns inspection or quarantined as damaged. What’s left after all that is the number the sales channels need: stock that is sound, uncommitted and able to ship today.

In our example, 400 units might be in FBA cartons waiting for collection, 600 are reserved for the B2B order, 80 are in returns inspection and 50 are allocated to open webshop orders. The seller thinks in terms of 3,000. The channels can safely sell 1,870.

Overselling starts in the gap between those two figures. A channel that sees on-hand stock rather than available stock will keep accepting orders for units that already belong to someone else.

FBA replenishment and direct orders compete for the same unit

Holding buffer stock outside Amazon changes who controls replenishment. Instead of sending most of a container straight into Amazon’s network, the seller sends smaller, more frequent shipments from Germany and decides each time how much Amazon gets. Units still in Germany can go either way if a webshop campaign takes off or Amazon sales slow. Units already in an Amazon fulfilment centre are harder to redirect. Amazon’s Multi-Channel Fulfilment can ship orders from other sales channels out of FBA stock, which covers part of this, but the units stay in Amazon’s network and on Amazon’s terms. Getting them back out means a removal order.

That control isn’t free. Stock held outside Amazon costs storage and handling, and every replenishment shipment needs its own prep and transport. Hold too little and the buffer protects nothing. Hold too much and you’re paying for storage in two places while the forecast still has to be right. Sellers often watch Amazon’s storage fees closely and forget that the buffer has a cost too.

The harder problem appears when individual orders can consume the same units. Say available stock is down to 600 and the seller plans a 500-unit FBA shipment for Thursday. On Monday the webshop runs a promotion and sells 300, picked from the same location. Unless the system held back the 500, Thursday’s shipment is 300 units, and Amazon runs short two weeks later. Every order was legitimate. Nobody made a mistake at SKU level. What was missing was a rule for which channel gets the unit when two channels want it.

There are a few workable answers, and none is universal:

• Hard reservation. The FBA quantity is locked in the WMS when the shipment is planned, so direct channels can’t see those units.
• Protected floor. Direct channels sell down to a set level; below it, remaining stock is held for FBA.
• Priority by cost of stock-out. Whichever channel hurts most when it runs dry gets first claim.

A brand earning most of its revenue on Amazon should probably protect FBA first. A brand building its own webshop might accept a thinner Amazon buffer. What matters is deciding in advance rather than letting order sequence decide.

Cut-offs matter too. FBM orders carry the dispatch promise the seller has set on Amazon, and webshop customers expect something similar. FBA shipments are prepared in batches. If both draw on the same pick faces on the same afternoon, the warehouse needs to know which comes first when labour is tight, not only when stock is.

Labelling for Amazon changes where a unit can go next

Amazon needs a scannable barcode on every unit it receives. Depending on the seller’s barcode settings and eligibility, that’s the manufacturer barcode or an Amazon FNSKU label. Cartons have to meet Amazon’s weight, dimension and labelling rules, which have changed often enough recently that they’re worth checking in Seller Central before each peak rather than copying from last year’s SOP.

For a shared pool, the question is when to label. Label everything with FNSKUs on arrival and every unit is ready for Amazon, but it also carries an Amazon label into every other channel. On a webshop parcel that rarely matters; a retail buyer may not want it. Label per FBA shipment and the pool stays neutral, at the cost of an extra step each time stock goes to Amazon. At 200 units a month the difference barely registers. At 20,000 it becomes a staffing question.

A B2B order is not a large B2C order

B2B stock usually moves in cartons or on pallets, not as picked single units. The buyer may specify carton quantities, pallet height, labels, delivery slots or paperwork. A webshop order takes one unit from an open carton. A wholesale order often wants full, unopened cartons, so the warehouse has to know how many full case-packs it holds, not just how many units.

This is usually where the workflow breaks. If single-unit orders have been picked from many cartons, the pool can hold well over 600 units and still only 35 full cartons of 12. The 600-unit order needs 50. It can’t ship as ordered without repacking, which takes time and packaging the buyer may not accept.

B2B orders also take a large share of the pool in one go. Our 600 units are a fifth of total stock. Reserve them the day the order is confirmed, not the day it’s picked, or other channels will sell into it in between.

Packaging obligations split along similar lines. Since 12 August 2026, German packaging rules sit in the VerpackDG, which replaced the Packaging Act (VerpackG). Packaging that typically ends up with private households is treated differently from transport packaging that stays in commercial supply chains. A seller shipping both from one warehouse should check that its registration and system participation (Systembeteiligung) cover both.

Tax is a separate question. Selling the same goods to a business customer, to a consumer through Amazon and to a consumer through your own shop can have different VAT consequences, depending on things like where the seller is established, who the buyer is and whether a marketplace facilitates the sale. From the warehouse, we can tell you which route each unit took and what documents went with it. What that means for VAT is a question for a tax adviser, and it’s better asked before the channel mix is set than after.

When inventory moves backwards

Webshop returns come back to the German warehouse. Amazon inventory can too, through removal orders that ship units from Amazon’s fulfilment centres to an address the seller chooses.

Neither is saleable on arrival. Each unit must be received against an expected quantity, inspected and graded. It might be resaleable as new, need repackaging, need its FNSKU label covered or replaced, be sellable only as B-stock, or be written off. Removed FBA units often arrive in mixed cartons with an Amazon label on every item. That’s convenient if they’re going back to Amazon and a problem if they’re meant for a B2B order.

Then someone must decide which pool a graded unit rejoins. That’s a commercial decision, not a warehouse one. The warehouse can report 80 units in grade A condition. It shouldn’t be the one choosing between FBA, the webshop and a discount channel. When nobody owns that call, returns sit in a quarantine location and stock that looks unavailable is really waiting for a rule.

Removal itself is a trade-off. Amazon’s removal fee plus inbound handling and re-prep can exceed the value of cheap units, and disposal or liquidation may make more sense. For higher-value stock, pulling slow movers back into the German pool can be a sensible way to redeploy them. We’ve described how Amazon returns and removals are inspected and routed in a German warehouse.

What a shared pool costs to run

Shared stock lowers the risk of having units in the wrong place. It raises the number of rules that must be right.

Every channel added means another integration to keep in sync, another order profile, another set of cut-offs and another path for exceptions. If one channel’s stock feed updates every 15 minutes and another’s every hour, there’s a window in which both can sell the last units. The WMS must support reservations by channel, and someone must own the allocation rules and revisit them when demand shifts.

For some sellers that isn’t worth it. With low volume, with Amazon as nearly all of revenue, or with large and predictable B2B orders, dedicated stock can be the safer choice: a fixed B2B allocation kept apart from what feeds FBA, with no dynamic reallocation between them. Splitting by channel gives up some flexibility and gains predictability. Early on, that’s often the better trade.

A shared pool pays off when demand across channels is uncertain, and the seller has the data and discipline to run the rules. It works badly when it’s used to avoid forecasting rather than support it.

Questions to answer before the stock arrives

When FBA replenishment and a direct order both want the last units, which one wins, and is that written into the system or left to whoever picks first? How quickly can a unit planned for one channel move to another, and what does the move cost? What figure does each sales channel see: on-hand stock, or stock available after reservations? When returned or removed units are graded, who decides where they go? And how much buffer protects the next FBA shipment from a good week somewhere else?

With those answers in place, one German stock pool can serve several channels and stay reliable. Without them, the seller has one warehouse and several channels selling the same units.

Infographics by Małgorzata Matczak.