Subcontracting vs external processing in S/4HANA: tell them apart by their postings

Both of these mean “someone outside does part of the work.” They are configured differently, they post differently, and picking the wrong one gives you a cost structure you cannot analyse later. The fastest way to keep them straight is not the definition — it is the accounting entry each one produces.

What follows are the actual postings from two products made side by side in the same S/4HANA client: kimchi dumplings made by a subcontractor, and shrimp dumplings made in-house with one outsourced operation.

Subcontracting: the vendor makes the product

We buy the semi-finished product as work. We supply the raw materials, the subcontractor shapes them, and a single goods receipt settles the entire arrangement. That one document fires several OBYC account-determination keys at once:

Posting at the subcontract goods receipt Amount OBYC key
Dr 5080 raw material consumed — supplied to subcontractor 4,200 GBB · VBO
Cr 1050 raw materials 4,200− BSX
Dr 5170 subcontract fee 4,000 FRL
Cr 9050 GR/IR — semi-finished 4,000− WRX
Dr 1080 semi-finished stock 8,200 BSX
Cr 5050 factory output — subcontract 8,200− BSV

Read the arithmetic and the model becomes obvious: 8,200 = 4,200 materials + 4,000 fee. The semi-finished product is worth exactly what we put into it. Operating expenses net to zero — the output credit cancels the input debits — because nothing was consumed by us; value simply changed shape.

The two keys to remember here are VBO (consumption of stock provided to a vendor — a special stock, still ours, sitting at their site) and BSV (change in stock from subcontracting). No production order is involved anywhere. The purchase order is the controlling object.

External processing: we make the product, one step is outsourced

Here the shrimp dumplings stay an ordinary production order. One routing operation is flagged for external processing, so releasing the order automatically generates a purchase requisition, and the receipt of that purchase order becomes an actual cost of the order. Three postings, in sequence:

Step Posting Note
External operation received Dr 5170 fee 4,000
Cr 9070 GR/IR — No Material 4,000−
a purchase order with no material gets its own clearing account
Raw materials issued (261) Dr 5060 6,700
Cr 1050 6,700−
ordinary VBR consumption — nothing was supplied to a vendor
Semi-finished received (101) Dr 1080 10,700
Cr 5040 10,700−
ordinary AUF output; order closes at variance 0 (6,700 + 4,000)

Notice what is missing compared with subcontracting: there is no supplied-components posting, because nothing left our plant as vendor-held stock. And notice what changed: the clearing account is 9070 (No Material) rather than 9050, and the receipt credits 5040 / AUF — the in-house path — because the order made the product, not the vendor.

The three ways to make the same thing

  In-house Subcontracting External processing
Who makes it our work center the vendor, entirely us — one operation outsourced
Controlling object production order purchase order production order
Components leg 261 → GBB-VBR supplied stock → GBB-VBO 261 → GBB-VBR
Conversion leg activity allocation vendor fee → FRL vendor fee → FRL
Receipt credit GBB-AUF BSV GBB-AUF
GR/IR account — (no vendor) 9050 (stock class) 9070 (No Material)
Variance handling full close machinery price difference at invoice full — the fee is ordinary order cost

The OBYC keys are the fingerprint: VBR/AUF vs VBO/BSV vs VBR/AUF + FRL.

Why the distinction is worth caring about

The same kilogram of pork, consumed two different ways, lands on two different expense accounts — 5060 when we use it ourselves, 5080 when a subcontractor uses it on our behalf. That is not bureaucracy. It means that a year later somebody can ask “how much of our material cost went through outside partners?” and the chart of accounts can answer, without a single spreadsheet.

Choosing the wrong model quietly destroys that. If you model true subcontracting as external processing, you get a production order that never produced anything, and supplied material that looks like own consumption. Everything still balances — that is the trap. The books will be correct and the analysis will be useless.

A short decision rule that holds up in practice:

  • Does the vendor deliver a material you keep in stock, made from components you sent them? Subcontracting.
  • Does the vendor perform a step in the middle of your own routing, and the thing comes back to your line? External processing.
  • Is there no material at all — just a service? Neither; that is a plain service purchase order, and it will find its way to a cost center, not a product.
FROM THE SAME PROJECT

These postings come from one small company built from an empty S/4HANA client and driven through a complete business month — then extended with subcontracting, external processing, and a custom movement type. Written up as two books: a business novel for people meeting SAP for the first time, and a technical build record with the full OBYC matrix, every document number, and the tables behind each step.

See both books

Account numbers shown are from this build's chart of accounts; the OBYC keys (GBB/VBR/VBO/AUF, BSX, BSV, WRX, FRL) are standard and will be the same in your system. Which G/L account each key resolves to depends on your valuation class configuration.

New: a free 16-page sample of the novel — the prologue, Chapter 1 and the scene where 6,700 won of raw material disappears from the balance sheet. No email required.

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