Setup Step 15 — OBYC — FI Account Determination

MANDATORY Layer 3 · MM↔FI bridge ⏱️ ~30 min OBYC

🎯 Why this setting exists

OBYC is the shared heart of MM and FI. Every goods movement in MM has to land as a balanced FI document, but the user posting a goods receipt never types a G/L account — so SAP needs a rulebook that turns the movement into the right accounts automatically. That rulebook is OBYC. It maps a three-part key — transaction key × valuation class × chart of accounts — to the exact G/L account to debit or credit.

MM supplies two ingredients at posting time: the material's valuation class (from its Accounting view) and the movement type (which SAP translates into a transaction key like BSX or GBB). OBYC supplies the third: the G/L. Get this wrong and goods movements either post to the wrong account or fail outright — there is no MM transaction that touches stock value without passing through OBYC.

💡 Easy example

OBYC is the automatic rulebook that fires every time stock moves. When 50 t of iron (valuation class 3000) is received at Karachi with movement type 101, nobody writes a journal entry — OBYC reads the rule and says:

Debit G/L 300000 — Inventory (raw materials) BSX
Credit G/L 191100 — GR/IR clearing WRX

The stock goes up on the balance sheet, and a "we've received it but not yet been invoiced" liability is parked in GR/IR — all with zero human typing. Later, when the supplier's invoice arrives (MIRO), GR/IR is cleared against the vendor. That is the whole magic of MM↔FI integration, and OBYC is where it is wired.

🔗 How this connects to everything else

OBYC sits at the exact seam between Logistics and Finance, so almost everything either feeds into it or fires through it. Here's the web — worth knowing cold, because most "GR won't post" tickets trace back to a missing OBYC row.

⬆️ Depends on (must exist first)

Step 5 — Valuation Level & Step 6 — Valuation Grouping Code: the VGC (e.g. VPK1, VAE1) lets one OBYC rule serve many plants, or splits them when their accounts differ.
Step 1 — Chart of accounts + G/Ls: the target accounts (300000, 191100, …) must already exist in the chart, or OBYC has nothing valid to point at.
The material's valuation class (on its Accounting view) — e.g. 3000 for raw, 7920 for finished — which selects the right OBYC row.

⬇️ Enables (what this unlocks)

Every goods-movement posting. The GR in Scenario 1 (Inventory / GR-IR via BSX + WRX).
Consumption in Scenario 3 (movement 201 to cost center, 261 to order — via GBB).
Returns, scrapping, stock transfers and inter-company STO — all post through OBYC keys.
Invoice price differences at MIRO (via PRD).

🧩 Who owns it & why MM cares

MMFI The shared MM↔FI heart. MM supplies the valuation class + movement type; OBYC maps (transaction key × valuation class × chart) → the exact G/L. Get this wrong and goods movements either post to the wrong account or fail outright. Usually configured together by the MM and FI consultants — neither owns it alone.

🔮 Links to other modules (now & later)

FI The target G/Ls live in FI's chart of accounts; FI owns the account itself, MM owns the mapping to it.
CO Consumption (GBB-VBR) flows to a cost center or order, so the expense lands in Controlling, not just FI.
SD Goods issue for a delivery (GBB-VAX) books COGS — the MM side of an SD sale.

🔧 Configuration — fields & steps

OBYC · SPRO → MM → Valuation and Account Assignment → Account Determination → Account Determination Without Wizard → Configure Automatic Postings

⚙️ IDES is usually pre-configured — but VERIFY

A fresh IDES system normally ships with OBYC populated for chart INT. Your job here is to verify the keys below resolve to a valid G/L for your valuation grouping codes (VPK1, and VAE1 if you activated VGC) and your valuation classes (3000 raw, 7920 finished). The first goods receipt you attempt will fail loudly if any row is missing.

How the three-part key works

At posting time SAP builds the account-determination key from up to four things. Not every key uses all four — BSX/WRX are simple, GBB adds a "general modification":

Chart of accounts — e.g. INT (so the same config can differ per chart).
Transaction key — what kind of posting it is (BSX = inventory, WRX = GR/IR, GBB = offsetting, PRD = price diff).
Valuation grouping code — e.g. VPK1 / VAE1 (groups plants that share accounts; needs VGC active).
Valuation class (+ for GBB, a general modification like VBR/VAX/BSA) — e.g. 3000, 7920.

Example resolution: chart INT × key BSX × VGC VPK1 × val. class 3000 → G/L 300000.

The transaction keys to verify

Transaction Key	Used for	Dr / Cr behaviour	Driven by	Example G/L
BSX	Inventory posting	Dr at GR (stock value up)	Valuation class	300000 raw, 200200 FG
WRX	GR/IR clearing account	Cr at GR; Dr at MIRO (clears)	(usually one G/L)	191100
GBB	Offsetting entry for goods movements — needs a general modification (below)	Dr or Cr depending on movement	Gen. mod. + valuation class	see GBB rows
PRD	Price differences (std-price materials, MIRO variances)	Dr or Cr the variance	Valuation class	231000
KBS	Account-assigned PO (cost center / order posted directly)	per movement	—	(G/L specified on the PO line)

🔑 GBB general modifications (VBR, VAX, BSA …) — the offsetting account

GBB ("offsetting entry for inventory posting") covers many different movements, so it is split by a general modification code. The same GBB key resolves to a different G/L depending on the modification + valuation class:

GBB modification	Used for	Example G/L
VBR	Consumption to a cost center / internal use (e.g. movement 201, 261 — production issue)	400000
VAX	COGS — goods issue for a delivery (sales, no account assignment)	500000
BSA	Initial stock entry / stock balancing (e.g. movement 561 — load opening stock)	399999

So a production issue (261) hits GBB-VBR → 400000; a delivery goods-issue hits GBB-VAX → 500000; loading opening stock hits GBB-BSA → 399999. All under the one GBB key.

Action — verify (and fix) each key

Run OBYC.
For each transaction key above, double-click it → confirm entries exist for your VGC VPK1 (and VAE1 if you activated VGC; or a blank VGC if you did not).
For BSX / WRX / GBB: also confirm a row exists per valuation class — 3000 (raw) and 7920 (finished).
For GBB: confirm the needed general modifications (VBR, VAX, BSA) each resolve to a G/L.
If any row is missing, add a new entry pointing to a valid G/L from your chart of accounts, then Save.

🚨 Issues & fixes

❌ The classic GR failure (straight from Scenario 1)

When you attempt the first goods receipt and the inventory account isn't mapped, SAP stops the posting with:

Account determination for entry INT BSX ___ ___ valuation class 3000 not possible

Meaning: in chart INT, the BSX (inventory) key has no G/L for valuation class 3000 — so SAP doesn't know which account to debit and refuses to post.

Fix: OBYC → double-click BSX → add the row for valuation class 3000 → enter the inventory G/L (e.g. 300000) → Save. Re-run the GR; it now posts Dr 300000 / Cr 191100.

Error	Cause	Fix
"… entry INT WRX … not possible"	GR/IR clearing key (WRX) not mapped	OBYC → WRX → assign G/L `191100`.
"… GBB VBR … valuation class … not possible" on a 201/261 issue	Consumption modification missing	OBYC → GBB → add VBR row for that valuation class → consumption G/L (`400000`).
Postings land in the wrong account	Right key, wrong G/L for that valuation class / VGC	Correct the G/L on that specific row in OBYC; check you edited the correct VGC.

This and other account-determination errors are catalogued in the Troubleshooting Center.

✅ Verification

In OBYC, BSX resolves to an inventory G/L for both valuation class 3000 and 7920 under your VGC.
WRX resolves to GR/IR 191100; GBB-VBR to a consumption G/L; PRD to a price-difference G/L.
A test goods receipt (movement 101) posts Dr Inventory / Cr GR-IR with no account-determination error — the live proof from Scenario 1.
A test consumption (movement 201/261) posts to the cost center / order via GBB-VBR — see Scenario 3.

✅ Step 15 complete — OBYC verified for all keys

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Step 14: Customer / Vendor for Inter-Co STO

Step 16: SD Setup for Inter-Company STO