Invoice fraud costs businesses billions annually, yet many companies focus exclusively on external cyber threats while overlooking traditional invoice manipulation schemes. Understanding common fraud patterns helps credit professionals identify and prevent these costly attacks.
The FBI’s IC3 2024 annual fraud report showed that Business Email Compromise (BEC) accounted for $2.77 billion in reported losses from over 21K complaints filed.
Fake Invoice Schemes
How It Works: Fraudsters send invoices for goods or services never ordered or delivered. They often impersonate legitimate suppliers or create convincing fake company identities.
Red Flags:
- Invoices for services slightly outside your typical needs (cleaning, maintenance, consulting)
- Urgent payment requests or threats of service disruption
- Requests to update payment information or banking details
- Generic descriptions like “services rendered” without specifics
- Round numbers without itemization
Prevention: Verify all invoices against purchase orders. Never pay an invoice without confirming someone authorized the purchase.
Invoice Interception
How It Works: Fraudsters intercept legitimate invoices (through compromised email accounts or mail theft), alter payment details, and send them to your AP department with fraudulent banking information.
Red Flags:
- Supplier suddenly requests payment method changes via email
- Banking details differ from established records
- Email addresses that are slightly different from legitimate supplier addresses
- Unusual urgency around payment instructions
Prevention: Always confirm banking detail changes through secondary communication channels—call the supplier’s known phone number, don’t reply to suspicious emails.
Business Email Compromise (BEC)
How It Works: Attackers compromise executive email accounts and instruct AP or credit teams to make urgent payments to fraudulent accounts, often claiming confidential acquisitions or emergency vendor payments.
Red Flags:
- Executive requests bypassing normal approval processes
- Unusual urgency or confidentiality demands
- Requests for wire transfers rather than standard payment methods
- Communication patterns inconsistent with the executive’s normal style
Prevention: Implement verbal confirmation requirements for unusual payment requests, especially wire transfers. No email request alone should authorize payments outside standard procedures.
Duplicate Invoice Fraud
How It Works: Fraudsters submit legitimate invoices a second time, hoping AP departments will pay twice. Sometimes they alter invoice numbers slightly to avoid detection.
Red Flags:
- Same vendor, similar amounts, close timing
- Invoice numbers that differ by only one digit from previously paid invoices
- Multiple invoices for identical amounts from the same supplier
Prevention: Robust invoice matching systems that flag potential duplicates. Maintain clear records of paid invoices.
Overbilling Schemes
How It Works: Suppliers inflate quantities, prices, or services on invoices, hoping no one verifies against actual delivery or contract terms.
Red Flags:
- Invoices exceeding contracted rates
- Quantities that seem excessive for the project or period
- Services billed but not authorized or performed
Prevention: Three-way matching, purchase order, receiving documentation, and invoice must all align before payment. Regular contract compliance audits.
Shell Company Fraud
How It Works: Internal employees or collusive vendors create fake companies, submit fraudulent invoices, and direct payments to accounts they control.
Red Flags:
- New vendors with limited business history
- Vendor addresses matching employee addresses
- No web presence or minimal online footprint
- Services difficult to verify (consulting, professional services)
Prevention: Vendor verification processes including business registration checks, tax ID verification, and reference validation before establishing vendor relationships.
Protection Strategies
Segregation of Duties: The person approving invoices shouldn’t also process payments. The person entering vendor information shouldn’t approve vendors.
Vendor Master File Controls: Restrict who can add or modify vendor records. Require approval for banking detail changes. Regularly audit vendor master files for duplicates or suspicious entries.
Payment Verification: Implement confirmation processes for large or unusual payments. Require dual authorization above certain thresholds.
Employee Training: Most fraud succeeds because busy staff don’t recognize warning signs. Regular training on current fraud schemes improves detection.
Technology Tools: Many accounting systems now include fraud detection features, duplicate invoice detection, payment pattern analysis, and vendor validation checks. Enable and monitor these tools.
What To Do If You Suspect Fraud
Document everything: Preserve the suspicious invoice, all communication, and any evidence immediately.
Don’t confront the suspected party directly: This gives fraudsters opportunity to destroy evidence or escalate the scheme.
Notify appropriate parties: Internal audit, legal counsel, law enforcement if warranted. External fraud should be reported to your vendor immediately.
Review controls: Understand how the fraud occurred and what control failures enabled it. Prevention of future incidents depends on addressing root causes.
The Reality
Invoice fraud succeeds because it exploits trust, process gaps, and human error. No company is too small or too sophisticated to be targeted. Fraudsters constantly evolve tactics, so vigilance must be continuous.
The best defense combines strong processes, appropriate system controls, employee awareness, and healthy skepticism. When something seems unusual, invoice format differs, payment instructions change, urgency feels manufactured, pause and verify.
Prevention costs far less than recovery. Implementing proper controls and training might seem burdensome, but the alternative, discovering significant fraud after the fact, is exponentially more costly and damaging.
Invoice fraud prevention is just one aspect of risk management in credit control. For more fraud detection strategies and risk mitigation guidance, follow our Fraud Friday series or explore Chapter 4 of The Head of Credit & Collections Handbook (out soon) for comprehensive coverage of credit risk assessment and protection.
