AP Fraud Playbook: How to Identify and Mitigate Risks in Your Accounts Payable Process
AP fraud often hides in plain sight. If your team struggles to spot invoice fraud red flags or tighten vendor master controls, you’re not alone, and there’s a way forward. This playbook breaks down practical steps to spot risks, strengthen your payment approval workflow, and build fraud prevention into your daily routine.
Reality check: In the 2025 AFP Payments Fraud and Control Survey, 79% of organizations reported attempted or actual payments fraud in 2024, and only 22% recovered 75% or more of the funds lost. (Source: AFP press release)
Let’s get your controls working smarter, not harder.
Identifying AP Fraud Risks
Understanding the risks in accounts payable is crucial to protecting your organization. Recognizing common fraud schemes is the first step toward a stronger defense.
Common Fraud Schemes and Red Flags
Many fraud schemes can target your accounts payable process. Fake invoices, altered payment details, and duplicate payments are a few examples. Unusual vendor requests for changes in payment details or last-minute invoice submissions can signal fraud. Be especially cautious with vendors you’ve never heard of, and verify vendor details using independent sources.
High-signal red flags experienced AP teams watch for:
- Invoice amounts that repeatedly land just under an approval threshold.
- Round-dollar invoices (for example, $5,000 or $10,000) with vague descriptions.
- Vendor address is a P.O. box only, a residential address, or matches an employee address.
- A sudden spike in payments to one vendor without a matching increase in POs, receipts, or volume.
- Bank account or remit-to changes paired with urgency (“pay today” or “we’ll stop service”).
- Sequential invoice numbers with gaps, duplicates, or “too perfect” patterns.
- Multiple vendor records sharing the same bank account, email domain, phone, or tax ID.
- Unusual timing (late night approvals, weekend changes, or rush payments right before month-end).
Business Email Compromise (BEC): The Payment Change Trap
One of the most common real-world fraud scenarios is an email that looks like it came from a vendor, your CFO, or a senior leader asking for a bank change or a rush payment. The message is often calm, plausible, and urgent.
Example (what it can look like):
“Hi AP Team, we updated our banking details. Please send today’s payment to the new account below. We’re trying to avoid a service interruption.”
Controls that stop BEC cold:
- Out-of-band verification for any bank change or high-risk payment (call a known number on file, use a vendor portal, or a documented ticket).
- Dual approval for vendor master changes, separate from invoice approval.
- Payment holds for banking changes until verification is completed and documented.
- Clear escalation path: AP should feel supported when they slow down a “rush” request.
Vendor Onboarding Best Practices
Proper vendor onboarding is essential in preventing fraud. Start by verifying each vendor’s information thoroughly. Use a checklist to ensure every required document is reviewed. Cross-check vendor addresses and banking details with official records, and require dual approval for any changes to vendor information.
Practical vendor onboarding checklist (one-page version):
- Validate legal name, tax ID, and address against authoritative sources (not only what the vendor emails you).
- Verify banking changes out-of-band (call a known phone number on file, not a number from the request).
- Require role-based approvals for new vendor setup and for vendor maintenance (separate from invoice entry).
- Block “free email” domains for banking changes unless reviewed (for example, Gmail or Yahoo) when policy allows.
- Log every change to vendor master data and review a weekly change report.
Invoice Fraud Red Flags
Invoice fraud can go unnoticed if not properly managed. Look out for invoices that lack detail or contain vague descriptions. Comparing invoices to purchase orders and delivery receipts can help verify authenticity. Also, watch for duplicates that can lead to double payments, especially when vendors submit “revised” invoices.
Quick invoice checks that catch real-world fraud:
- Same invoice number, same amount, or same remit-to across multiple submissions.
- Mismatch between vendor name and remit-to entity (or slight name changes that look intentional).
- Service invoices without dates, scope, rate detail, or an internal requester.
- First-time vendor invoices that bypass the normal PO process.
- Invoices that reference a PO you cannot find in your system.
Strengthening AP Controls
Once you know the risks, it’s time to fortify your controls. This section covers key practices to bolster your AP defenses.
Segregation of Duties Importance
Segregation of duties is a cornerstone of strong internal controls. It ensures no single person handles all aspects of a transaction. This division reduces the risk of fraud and errors. For example, the person authorizing payments should not be the person processing them. Regularly review your workflows to confirm duties are appropriately divided, and document any necessary exceptions.
Three-Way Match and Positive Pay
The three-way match compares the invoice, purchase order, and receiving report before payment. It helps prevent paying for goods not received and exposes pricing and quantity mismatches. Positive Pay is a bank service for check payments where your issued-check file is matched against checks presented for payment. Many banks also offer Payee Positive Pay, which helps confirm the payee name. If your organization relies on ACH or wires, ask your bank what verification and fraud-control options they offer for electronic payments.
Vendor Master Controls and Duplicate Detection
Maintaining accurate vendor master data is crucial. It helps prevent duplicate payments and unauthorized changes. Regular audits of vendor information can identify inconsistencies. Use automated checks to detect duplicates and flag unusual edits (like bank changes, address changes, or email changes). A clean vendor master reduces fraud risk and improves AP efficiency.
Leveraging Technology and Training
Technology and training are powerful allies in the fight against fraud. They equip your team with tools and habits that reduce risk every week, not just after something goes wrong.
AI Fraud Detection in AP
Artificial Intelligence (AI) can strengthen fraud detection, but it works best as an added layer on top of strong core controls (segregation of duties, approvals, and three-way match). In practice, AI tools help by finding patterns humans miss at scale.
Where AI and automation usually add value first:
- Duplicate detection beyond invoice number (same amount, same date range, similar descriptions, or same bank account across vendors).
- Anomaly alerts (unusual payment timing, sudden vendor spend spikes, new payees, unusual approver behavior).
- Vendor master monitoring (bank changes, address changes, email changes, and “near-duplicate” vendor records).
- Exception routing (sending high-risk invoices to a higher approval tier or a second reviewer).
Phishing Drills and Culture Building
Phishing scams are a common entry point for fraud. Regular phishing drills can train your team to recognize and avoid these threats. Culture matters just as much: encourage quick escalation, reward caution, and treat “slow down and verify” as good performance.
Continuous Monitoring and KPIs
Continuous monitoring of transactions is essential. Set key performance indicators (KPIs) that reflect both control coverage and control quality. Review them regularly to spot drift before a fraud event forces a reset.
Simple KPI dashboard ideas that AP leaders actually use:
- % of spend and invoices processed with three-way match (where applicable).
- Vendor master change volume per week (and % with dual approval and documented verification).
- Duplicate payment rate (confirmed duplicates per 1,000 invoices).
- Rush payments as a % of total payments (and how often the rush bypassed standard workflow).
- Exception queue aging (how long high-risk items sit before review).
60-Second AP Fraud Self-Assessment
Answer these quickly. If you have two or more “no” answers, your fraud risk is likely higher than you think.
- Do we require out-of-band verification for all vendor bank changes?
- Is vendor master maintenance separated from invoice entry and payment release?
- Can we produce a weekly vendor change report, and does someone review it?
- Do we have strong duplicate detection beyond invoice number only?
- Do “rush” payments still follow a documented workflow with approvals and evidence?
The AP fraud landscape is challenging, but with the right strategies, you can protect your organization from potential losses. Proactive controls, consistent monitoring, and a culture that supports verification can prevent expensive mistakes.
Want a quick AP fraud controls review?
If you want a second set of eyes on your AP workflow (vendor changes, approvals, duplicate detection, and payment controls), book a short call and I’ll help you map the biggest risks and the fastest fixes.
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Robert Ruhno
Executive Director APPG
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