Guide to Accounts Payable Fraud – With Prevention Strategies

Accounts Payable (AP) departments, responsible for processing millions in payments for mid to large-scale businesses, are uniquely susceptible to fraud. Unlike typical consumer scams, accounts payable fraud schemes are often intricate, often involving a combination of internal collaboration, external manipulation, and system vulnerabilities. 

It may involve employees colluding with vendors, cybercriminals impersonating suppliers, or duplicate invoices slipping through during high-volume processing. The fallout is severe: mounting financial losses, compliance penalties that expose companies to legal risks, and a decline in vendor and employee trust. If not addressed, such fraud can lead to significant financial losses, penalties for non-compliance, and a decline in organizational trust.

This guide will detail the mechanics and various forms of AP fraud, along with crucial detection and prevention strategies that finance leaders should prioritize.

Key Takeaways:

• AP Fraud as a Critical Risk
• Definition of AP Fraud
• How AP Fraud Works
• Why AP is Vulnerable
• Types of Fraud Schemes
• Red Flags to Monitor/ Common Fraud Examples
• Consequences of AP Fraud
• Detection Measures
• Prevention Strategies
• Role of Automation
• Final Message/ Scry AI’s Collatio Solution

What is accounts payable fraud?

Accounts payable (AP) fraud is the theft or misdirection of a company’s funds by exploiting weaknesses in the payment process. It targets the AP function, the team, and systems that set up vendors, process invoices, and disburse payments, and can be perpetrated by insiders (employees), outsiders (vendors or cybercriminals), or through collusion between them.

This type of fraud capitalizes on weaknesses in invoice verification, vendor onboarding, and payment authorization procedures. Unlike accidental errors, AP fraud is characterized by deliberate deceit aimed at circumventing financial controls.

Accounts Payable (AP) fraud works by exploiting vulnerabilities in the payment cycle, from invoice submission to final disbursement. Fraudsters, whether insiders, outsiders, or both in collusion, manipulate weak controls, poor oversight, or manual processes to siphon funds.

According to the Association of Certified Fraud Examiners (ACFE) 2024 Report to the Nations, organizations lose an estimated 5% of annual revenue to fraud, with billing and payment fraud schemes being among the most common in financial functions. For mid-to-large enterprises, this translates to millions of dollars in annual losses.

How does accounts payable fraud happen?

Accounts payable fraud works in multiple ways. A few of which are:

1. Creating or manipulating vendor records

• Fraudsters may set up fake vendors, creating vendor fraud in the system, or alter legitimate vendor details to reroute payments.
• In insider cases, employees can add “ghost vendors” and approve invoices under their control.

2. Submitting false or inflated invoices

• Invoice fraud: Invoices are fabricated for goods or services that were never delivered.
• Real invoices are inflated with altered quantities or prices.
• Duplicate invoices are submitted to trick the system into paying twice.

3. Exploiting approval and payment gaps

• Weak segregation of duties allows the same employee to create, approve, and process invoices.
• Fraudsters may time payments during high-volume cycles to avoid scrutiny.

4. Payment diversion

• Payments are redirected to fraudulent accounts by tampering with bank details or through check fraud.
• Social engineering or phishing is often used to impersonate vendors and request changes in payment instructions.

5. Collusion between insiders and vendors

• Employees and vendors cooperate to overbill, split illicit profits, or conceal fraudulent payments within bulk transactions.

Why are AP departments at high risk?

The AP function deals with high transaction volumes, multiple stakeholders, and diverse vendor relationships. This complexity makes it an attractive target for fraud in accounts payable. Factors that increase risk include:

• Reliance on manual processes and spreadsheets
• Lack of segregation of duties within finance teams
• Pressure to meet payment deadlines without thorough verification
• Increasingly sophisticated cyberattacks targeting payment data

A 2023 PwC Global Economic Crime and Fraud Survey found that 46% of organizations experienced fraud in the past 24 months, with payment fraud ranking among the top five most disruptive types. Over $42 billion in global losses were reported across industries (PwC Global Fraud Survey 2023).

Types of accounts payable fraud

Accounts Payable fraud takes multiple forms, but it can broadly be divided into internal and external schemes. Internal fraud is often the hardest to detect, as it originates from trusted employees who already have access to AP workflows.

Internal accounts payable fraud

Internal fraud originates from employees or insiders with access to AP workflows. These kind of internal fraud involves:

• Billing Schemes: Employees create fake invoices or shell vendors to route payments to themselves.
• Check Fraud: Fraudsters intercept or alter checks before they are cleared.
• Kickback Schemes: Employees collude with vendors to approve inflated invoices in exchange for personal rewards.
• Expense Reimbursement Fraud: Staff submit false or inflated reimbursement claims for personal gain.

External accounts payable fraud

External threats exploit system loopholes and vendor relationships. These kind of external fraud involves:

• Business Email Compromise (BEC): Fraudsters impersonate vendors or executives via email to redirect payments.
• ACH and Wire Transfer Fraud: Cybercriminals intercept banking details to divert large sums.
• Duplicate or Multiple Invoice Submission: Vendors resubmit the same invoice, hoping duplicates go unnoticed.
• Ghost Vendors and Incomplete Goods/Services Invoices: Fraudsters create fake suppliers or bill for undelivered goods.
• Overbilling and Vendor Collusion: Vendors inflate charges or collude with insiders to approve inflated payments.

Red flags of AP fraud to watch for

Detecting potential fraud requires vigilance and awareness of accounts payable risk indicators that indicate irregularities in vendor payments or invoice processing. Some of the most common red flags include:

• Unusual Vendor Activity: Sudden creation of new vendors, duplicate vendor names, or vendors with incomplete information.
• Invoice Anomalies: Duplicate invoices, round-dollar amounts, inflated charges, or invoices that don’t match purchase orders.
• Vendor Master Data Changes: Frequent or unexplained changes in vendor bank details, contact information, or addresses.
• Bypassing Standard Approvals: Payments were pushed through without proper review, or invoices were consistently approved by the same individual.
• Payment Irregularities: Multiple payments just under approval thresholds, payments made outside normal cycles, or to offshore accounts.
• Employee-Vendor Relationships: Employees with close ties to vendors or unexplained conflicts of interest.
• System Access Red Flags: Staff with excessive privileges, such as the ability to create vendors and approve payments simultaneously.

Takeaway: Recognizing these red flags is the first step toward building stronger defenses. Organizations that actively monitor these signals are better positioned to prevent losses before they escalate.

Common AP fraud schemes in practice

Accounts payable fraud schemes rarely appear in isolation. Fraudsters often use creative tactics to disguise illegitimate payments as routine transactions, making detection difficult. Here’s how an organization can detect fraud:

Pass-through schemes

Employees set up shell companies to bill their employer for fictitious goods or services.

Example: An AP clerk creates a vendor account for a fake “supply company” and issues monthly invoices for office equipment that never arrives.

Disguised purchase schemes

Fraudulent expenses are masked as legitimate operating costs, blending into daily financial flows.

Example: A manager charges personal travel expenses to the company but codes them under “client meetings” to avoid scrutiny.

Vendor collusion and bribery

External vendors and employees work together to inflate contracts, approve fictitious services, or hide kickbacks.

Example: A vendor bills $150,000 for IT services worth only $100,000, splitting the extra $50,000 with the approving employee.

Duplicate invoicing

Fraudsters submit the same invoice multiple times to trigger repeated payments.

Example: A vendor sends two identical invoices with slight changes in invoice numbers, tricking AP into paying both.

Check tampering

Physical or digital checks are intercepted, altered, or forged before being cleared.

Example: An employee steals an issued check, changes the payee name, and deposits it into their personal account.

The cost and consequences of AP fraud for enterprises

Few financial risks are as damaging as Accounts Payable fraud. Beyond the immediate loss of funds, it undermines trust with vendors and employees, disrupts business continuity, and leaves enterprises exposed to long-term regulatory and reputational risks. Its impact extends far beyond financial write-offs, creating lasting vulnerabilities across the organization.

• Financial Losses and Write-Offs: Fraudulent invoices, duplicate payments, and diverted funds can cost enterprises millions annually. In many cases, these losses remain undetected for months, compounding the damage.
• Compliance and Regulatory Risks: Violations of SOX, AML, or other regulatory requirements due to inadequate internal controls. Fraudulent transactions may violate tax laws, anti-bribery regulations, and internal audit requirements. Failure to detect and report them can lead to regulatory fines and litigation.
• Reputational Damage in the Market: Loss of vendor trust and weakened corporate credibility. Discovery of internal or vendor-related fraud can undermine stakeholder trust, harm investor confidence, and damage the company’s public image.
• Internal Productivity and Trust Issues: Employee morale suffers when fraud is exposed internally, especially if it involves senior staff.
• Increased Audit and Insurance Costs: Enterprises hit by AP fraud often face higher audit scrutiny and rising insurance premiums, adding long-term financial strain.

How to Detect Accounts Payable Fraud

Managing accounts payable risk requires detecting AP fraud through proactive controls and continuous oversight. Enterprises that build multiple checkpoints across vendor, invoice, and payment workflows are far more likely to uncover fraud before it escalates.

• Fraud Risk Assessments: Conduct regular assessments to identify high-risk areas.
  Scenario: An enterprise identifies that manual invoice processing without dual approvals is its highest-risk area, prompting tighter review controls.

• Vendor Data Validation and Due Diligence: Cross-check vendor details against public databases and watchlists.
  Scenario: A background check reveals that a newly added vendor shares the same bank account as an existing employee, an immediate red flag.

• Invoice Matching and the Four-Eyes Principle: Match invoices with purchase orders and receiving reports, with dual approval checks.
  Scenario: A $25,000 invoice is flagged because it doesn’t have a matching purchase order, preventing payment before validation.

• Continuous Auditing and Monitoring: Leverage audit logs and anomaly detection tools to track suspicious activity.
  Scenario: Automated monitoring detects a vendor consistently billing round-dollar amounts just below the approval threshold, triggering an investigation.

• Whistleblowing & Reporting Mechanisms: Create safe, confidential channels for employees to report suspected fraud.
  Scenario: An anonymous employee tip reveals that a colleague has been colluding with a vendor to approve inflated invoices.

Accounts payable fraud prevention strategies

Preventing AP fraud requires building safeguards across people, processes, and technology. A layered approach ensures that fraud attempts are stopped at multiple checkpoints before they cause financial damage.

Designing strong internal controls

Enforce segregation of duties, multi-level approvals, and restricted system access.

• Problem: In a mid-sized enterprise, the same employee could create vendors, approve invoices, and process payments, making fraud easy to conceal.
• Solution: Roles are separated so one person enters invoices, another approves them, and a third processes payments, ensuring no single employee has unchecked authority.

Regular employee training and awareness programs

Keep staff updated on evolving fraud tactics and corporate policies.

• Problem: An AP clerk falls victim to a phishing email that impersonates a vendor, leading to a redirected $50,000 payment.
• Solution: Ongoing fraud awareness workshops teach employees how to spot phishing attempts, verify vendor requests, and report anomalies.

Policy enforcement and governance structures

Clearly define approval thresholds, payment terms, and accountability measures.

• Problem: Vendors consistently send invoices just under $10,000 because it bypasses management approval.
• Solution: A governance policy enforces random spot checks and staggered approval thresholds to prevent circumvention.

Automated AP workflows and approval chains

Digitize workflows to reduce manual intervention and errors.

• Problem: Paper-based invoices pile up, and duplicate payments slip through due to delayed manual reviews.
• Solution: Automated AP software routes invoices through pre-set approval chains, flags duplicates, and ensures audit-ready payment records.

Data analytics and AI for anomaly detection

Use predictive analytics and machine learning to identify suspicious trends in real time.

• Problem: A vendor repeatedly bills round-dollar invoices under $5,000 across multiple months, evading detection.
• Solution: AI-driven anomaly detection highlights unusual patterns, alerting finance teams before payments are processed.

Role of accounts payable automation in fraud prevention

AP automation plays a pivotal role in reducing fraud by eliminating manual vulnerabilities and embedding intelligent controls directly into the payment cycle. By digitizing workflows, organizations gain transparency, consistency, and proactive defense against fraudulent activity.

A 2022 Gartner report highlights that enterprises implementing AI-driven AP automation reduced fraud exposure by up to 70%, thanks to real-time anomaly detection, automated vendor verification, and intelligent invoice matching (Gartner Finance Research).

1. Automated invoice matching

• How it prevents fraud: Invoices are automatically cross-checked with purchase orders and receipts, blocking false or duplicate submissions.
• Case in point: A fraudulent invoice without a corresponding PO is instantly flagged before payment processing.

2. Segregation of duties by default

• How it prevents fraud: Automated systems enforce role-based access, ensuring no single employee can create, approve, and process invoices alone.
• Case in point: An AP clerk entering vendor data cannot approve payments, closing a common loophole.

3. Real-time anomaly detection

• How it prevents fraud: AI and analytics spot unusual billing patterns, such as inflated amounts or repeat invoices.
• Case in point: The system alerts finance leaders when a vendor suddenly submits multiple invoices just under approval thresholds.

4. Vendor validation & master data controls

• How it prevents fraud: Automation tools continuously verify vendor details against databases and watchlists, reducing fake vendor risk.
• Case in point: A new vendor setup is blocked because the tax ID matches an existing employee on file.
  

5. End-to-end audit trails

• How it prevents fraud: Every action, vendor creation, invoice approval, and payment is logged for full accountability.
• Case in point: Investigators can trace back approvals on a disputed invoice, identifying the exact user who pushed it through.
  

Conclusion: Building a fraud-resilient AP department

In a high-volume, high-risk AP environment, automation is more than efficiency; it is a defense against fraud in accounts payable. Combining strong internal controls with automated workflows ensures that red flags are not overlooked and fraudulent activities are intercepted early. By embedding AI-driven anomaly detection, real-time alerts, and transparent audit trails, enterprises can safeguard their finances along with their reputation and compliance posture. The strategic path forward is clear: a fraud-resilient AP department must be automated, intelligent, and vigilant.

How Scry AI’s Collatio Can Help

Scry AI’s Collatio AP Automation solution is built to safeguard enterprises from fraud by combining advanced 6-way invoice matching, contextual AI-driven anomaly detection, and vendor verification into one seamless platform. By embedding intelligence into every AP step, Collatio helps finance leaders reduce fraud risk, ensure compliance, and process invoices with confidence.

Experience AI-driven fraud prevention in action-Request a Collatio demo.