Ways money left without anyone knowing why.

A vendor’s bank details change by one or two digits over several invoices, each small enough to escape notice.

A near-duplicate vendor record (one character off the name) is created to receive a redirected payment.

Bank details are altered outside business hours, when no one is reviewing change requests.

An invoice references a purchase order that does not exist in the system.

The same invoice is submitted again with a trivially modified number (-A, -REV, extra zero).

Amounts land on exact round thousands far more often than genuine billing would produce.

Invoices priced just under an approval threshold to avoid a second signature.

One large purchase broken into several smaller invoices to stay below review limits.

A dormant or terminated vendor suddenly issues invoices again.

Remittance emails arrive from a domain one character off the real vendor’s.

Urgent “pay today for a discount” framing designed to bypass verification.

A spoofed executive request to wire funds urgently and confidentially.

A vendor’s tax ID quietly changes while the display name stays the same.

An amount’s currency is changed (USD→EUR) to inflate the paid value.

A small recurring charge for a service no one can identify, riding under scrutiny.

Invoiced quantity exceeds the PO by a small margin on every line.

An invoice dated into a prior, already-closed period to dodge current review.

Suspicious invoices clustered in weekend/holiday runs with reduced oversight.

A one-off “remit to a different account this time” note attached to a legitimate invoice.

The same invoice paid once in the ERP and again via a one-off manual payment.

Two vendor records for the same entity, one routing to a fraudulent account.

Unit price creeps above contract on invoices that otherwise look routine.

Payment for goods/services with no receipt confirming delivery.

An old approval reused to authorize a new, different invoice.

An automated system fabricates a plausible-looking PO reference that was never issued.

An invoice number reused across periods to mask a repeat payment.

A compromised real vendor mailbox sends genuine-looking invoices with new bank details.

Cent-level over-billing across thousands of lines, invisible per invoice.

A charge for an item not in any approved catalog or contract.

A spike of low-scrutiny invoices pushed through during period-close pressure.