3805622 - Invoice reversal or credit memo blocked with 'Moving Average Price would become negative' after wrong currency posting — SAP S/4HANA Cloud Public Edition

• A supplier invoice was posted using the wrong currency, which inflated material value and the moving average price (MAP).
• Attempting to cancel the supplier invoice shows error: “Moving Average Price would become negative.”
• Posting a credit memo to adjust the invoice triggers the same error.
• Error code: M8783.

• SAP S/4HANA Cloud Public Edition
• Fiori UI for Invoice Verification (Public Cloud)

1. Open the Cancel Supplier Invoice Document app.
2. Enter the invoice document number and fiscal year.
3. Set Reversal reason to 01 (Wrong posting) and choose a posting date.
4. Post the reversal and observe the error “Moving Average Price would become negative” (M8783).

• The supplier invoice was posted in the wrong currency, which overvalued the inventory and increased the MAP.
• Subsequent issues/consumption at the inflated cost moved part of that overvalue to expense, reducing remaining stock value.
• Reversal or credit memo would reduce stock value by more than what remains, leading to a negative MAP check (M8783), which cannot be overridden.
• The currency on a posted invoice cannot be edited.

1. Gather current values:
2. Read current MAP, stock quantity, and stock value for the material/plant in Manage Material Valuations (F2680) or Material Documents Overview (F1077).
3. From the invoice’s journal entry (Manage Supplier Invoices), note the amount posted to the inventory G/L (Stock_amount).
4. Determine the correct invoice value that should have been posted in the correct currency (Correct_value).
5. Confirm open posting periods and whether Material Ledger actual costing is active.
6. Determine if reversal will be blocked:
7. If current stock value (Value_now) ≥ Stock_amount, the cancellation should post without additional steps.
8. If Value_now < Stock_amount, compute Shortfall = Stock_amount − Value_now, and add a small buffer.
9. Unblock the reversal (if Shortfall exists):
10. In Manage Material Valuations (F2680), post a Debit/Credit Material to add Shortfall (+ buffer) to the material value in the current open period.
11. Cancel the incorrect invoice in Manage Supplier Invoices using a posting date in the current open period.
12. Post a new supplier invoice in the correct currency and correct value against the same purchase order in the current open period.
13. Align MAP to the correct level:
14. Recheck current stock value and quantity (F2680).
15. Calculate the correct unit cost (Correct_MAP).
16. If needed, post an additional Debit/Credit Material so that stock value/quantity equals Correct_MAP.
17. Verify:
18. Confirm MAP and stock value are correct in Manage Material Valuations.
19. Confirm the incorrect-currency invoice is cancelled and the corrected invoice is posted.
20. Confirm the vendor balance is corrected.
21. Operational guidance:
22. Test the full sequence in a non-production tenant.
23. Coordinate and obtain sign-off from Finance/Controlling.
24. Execute when no goods movements occur for the material; complete calculations and postings on the same day.

• refer to: 3755199 - Moving average price for material would be negative - Message no. M8783
• refer to: 3790977 - Moving Average Price Negative (M8783) During Invoice Posting Despite Price Change — Wrong Price Unit On Purchase Order
• refer to: Negative Stocks at Moving Average Price
• refer to: Manage Material Valuations
• refer to: Change Material Prices
• refer to: Material Documents Overview

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