Invoice fraud: What it is and how to protect your business

Invoice fraud involves submitting false or manipulated invoices to extract payments for goods or services that were never provided, or overcharging for those that were. From inflated charges to fake vendors, fraudsters are using increasingly sophisticated methods to exploit gaps in your accounts payable (AP) process for financial gain.

Incidents of attempted or actual invoice fraud increased by 10% year over year, from 14% in 2023 to 24% in 2024, according to a report from the AFP.

What is invoice fraud?

Invoice fraud occurs when someone deliberately creates false or manipulated invoices to extract unauthorized payments from your business. These tactics are designed to exploit weaknesses in your accounts payable processes, vendor management systems, or internal controls.

This differs from other financial fraud in its method and target. While credit card fraud involves stolen payment information, invoice fraud specifically attacks your payment workflow.

Fraudsters may impersonate trusted vendors, alter invoice details, or create entirely fake vendor accounts. In some cases, internal employees collaborate with them or overlook key details, making the fraud harder to catch. Without strong verification processes, these invoices can pass through your systems unnoticed.

How invoice fraud works

Invoice scams follow a methodical process that starts long before a fake invoice ever lands in your inbox. Attackers research your business, impersonate a trusted party, submit a fraudulent invoice, and quickly extract the funds before anyone notices.

Here's how a typical attack unfolds:

• Research phase: Fraudsters identify target companies and gather intelligence on vendors, billing cycles, and key finance personnel using public sources like LinkedIn, press releases, and company websites
• Impersonation: They create fake invoices from scratch or intercept and alter real ones, often using look-alike email domains or compromised vendor email accounts
• Submission: Attackers time their attacks strategically, often submitting fraudulent invoices during busy periods, at year-end, or when key finance staff are on vacation
• Extraction: Once payment is processed, funds move quickly through multiple accounts, making recovery nearly impossible

Understanding this lifecycle helps you spot interventions at each stage—from limiting public-facing vendor information to building verification steps that catch suspicious invoices before payment goes out.

Common types of invoice fraud

Invoice fraud takes many forms, and some are easier to detect than others. Recognizing how these tactics work in practice is the first step to preventing them.

Fake vendor invoices

Fraudsters send invoices for goods or services that were never ordered or received. These fake invoices are designed to look authentic enough to pass standard AP checks, often using real company logos and formatting copied from legitimate bills.

Invoice phishing and email scams

Attackers send invoice phishing emails that appear to come from known vendors, tricking employees into clicking links or downloading attachments. These email scams often contain malicious links that install malware or lead to fake portals designed to capture payment credentials.

Duplicate invoice fraud

Also known as double-payment fraud, this scheme involves submitting the same legitimate invoice multiple times. Fraudsters bank on automated systems or busy AP teams approving the duplicate without noticing it has already been paid.

Overbilling and inflated invoices

A legitimate vendor (or someone impersonating one) inflates prices, adds unauthorized charges, or bills for more items than were delivered. The padded amounts are often small enough to fly under the radar and avoid triggering manual review thresholds.

Vendor payment redirection

Also known as mandate fraud or supplier swap scams, this is one of the most common types of invoice fraud. Fraudsters pose as existing, trusted vendors and request an update to bank account details, diverting all future payments to an account they control.

Business email compromise (BEC)

In a BEC attack, attackers breach a legitimate vendor's email account to intercept real invoices. Before forwarding the invoice to you for payment, they alter the bank account details so the payment is redirected to them.

Internal employee fraud

Invoice fraud isn't always external. Dishonest employees can create fictitious vendors, submit fake invoices for personal gain, or approve fraudulent payments—sometimes colluding with external parties to bypass internal controls.

Consequences of invoice fraud

The damage from invoice fraud extends far beyond the initial payment. A single successful attack can ripple through your finances, operations, and reputation for months.

• Direct financial loss: Funds sent to fraudsters are rarely recoverable, directly hitting your bottom line
• Operational disruption: Your team spends valuable hours investigating the fraud, working with banks, and remediating issues instead of focusing on core finance work
• Damaged vendor relationships: When legitimate vendors don't get paid on time, it can strain or sever critical business relationships
• Compliance and audit issues: A successful fraud incident signals failed internal controls, which may trigger regulatory scrutiny, fines, and more intensive audits
• Reputational harm: Falling victim to fraud can erode trust among customers, investors, and other stakeholders

These consequences make a strong case for investing in prevention now rather than paying the cost of recovery later.

Warning signs of invoice fraud

Preventing invoice fraud requires identifying suspicious patterns before payment approval. These red flags serve as early warning signs that something may be off with an invoice:

• Unfamiliar vendors: Invoices from vendors with no prior history, or sudden changes to contact or payment information, should be verified
• Mismatched details: If invoice amounts, line items, or dates don't match the corresponding PO or delivery confirmation, that's a sign something may be off
• Duplicate submissions: Watch for repeated invoice numbers or amounts submitted close together. This could signal accidental or intentional duplication.
• Urgent or unusual payment terms: Requests for same-day payment or large discounts for immediate processing can be used to bypass scrutiny
• Missing documentation: A lack of supporting POs, receipts, or internal approvals should always trigger further review
• Formatting inconsistencies: Fraudulent invoices may use generic templates, lack branding, or have incorrect company details

Train your team to recognize these warning signs and establish clear protocols for flagging suspicious invoices. A culture of healthy skepticism can be the strongest defense against fraud attempts.

Invoice red flags checklist

Review every invoice against this checklist before processing payment:

Vendor information

• Vendor not in approved supplier database
• Contact information doesn't match records
• Generic email domain (e.g., Gmail) instead of a company domain
• Phone numbers that don't connect or go straight to voicemail

Invoice details

• Missing PO reference
• Vague product or service descriptions
• Incorrect tax calculations or missing tax ID
• Invoice number doesn't follow the vendor's usual format

Payment instructions

• Bank account changes without verification
• Payment to a foreign account when the vendor is domestic
• Requests for cryptocurrency or gift cards
• Instructions differ from the master vendor file

Timing and amounts

• Invoice dated before the PO
• Services billed before completion
• Amounts don't match contracts or quotes
• Rush payment demands without a valid reason

Impact by industry or company size

Understanding the specific fraud vulnerabilities within your industry is essential when developing effective prevention strategies:

By recognizing the common schemes targeting your sector, you can implement targeted controls or automated invoice processing software that address the highest-risk areas before fraudsters have an opportunity to exploit them.

How to prevent invoice fraud

Preventing invoice fraud requires a combination of strong internal controls for AP, automation, and team awareness.

Let's walk through how to protect your business using a practical example. Say you receive an invoice from your regular office supply vendor for $2,450 worth of printer toner cartridges.

1. Verify vendor details

Before processing payment, check that the vendor information matches your records. In this example, you notice that while the logo and company name look right, the invoice lists a different bank account number than previous invoices from that vendor. That's an immediate red flag.

2. Implement segregation of duties

Invoice approval should never come from a single person. Segregation of duties is a core internal control: the person entering the invoice should never be the same person approving payment.

For the $2,450 toner cartridge invoice, have one team member confirm the order was placed, another verify receipt of goods, and a third approve the payment amount against the original purchase order.

3. Call to confirm changes

When you spot the different bank account on the vendor's invoice, don't email the address on the invoice. Call the established vendor contact using the phone number from your records—not the one on the suspicious invoice. Your point of contact confirms they haven't changed their banking details. You've just caught a fraudulent invoice.

4. Match against purchase orders

Use 2-way matching to check whether the invoice for $2,450 of toner cartridges corresponds to an actual PO. If records show you only ordered $1,200 worth of supplies, or no recent order at all, something's wrong.

5. Train your team

Make sure everyone handling invoices knows what to look for. Show them the fraudulent vendor's invoice as a training example, pointing out the subtle differences from legitimate ones.

6. Establish payment thresholds

Set up different approval levels based on invoice amounts. For invoices over $2,000, require additional verification steps or senior management approval.

7. Use virtual cards with spending controls

Virtual cards add a powerful layer of security by limiting exposure. You can set transaction limits, restrict payments to specific merchants, and create single-use cards for one-time purchases. Payments made with virtual cards are also easier to trace and dispute than wire transfers, giving you more recourse if something goes wrong.

8. Employ technology

Use accounting software that flags unusual transactions and provides invoice audit trails. Smart systems would note that $2,450 for toner is significantly higher than typical office supply orders and flag it for review.

By following these steps, you'll create a solid defense against invoice fraud without sacrificing efficiency. A few extra minutes of verification can save thousands of dollars and countless headaches down the road.

Best practices for AP and finance teams

Your AP team is on the front lines of fraud prevention. Equip them with the right training and processes to identify and stop fraud attempts.

Train your team continuously

Conduct quarterly training sessions covering current fraud trends, real-world examples, and your company's specific procedures. Scammers are always evolving their tactics, so ongoing education is key.

Review and update processes regularly

Fraud tactics change, so your defenses need to adapt. Assess your controls annually, test their effectiveness, and adjust based on new threats or identified weaknesses.

Establish clear communication protocols

Create strict rules for handling vendor information:

• Verify any payment changes through a callback to a known, pre-verified phone number
• Never accept payment modifications via email alone
• Use a standardized form for payment updates that requires multiple signatures and verification steps

Create an invoice approval workflow

Build an effective approval process that follows these invoicing best practices:

1. Invoice receipt and entry: Direct invoices to a designated email address and enter them into an AP system, which validates the vendor against an approved list
2. Initial review: The AP clerk matches the invoice to a PO, verifies goods or services were received, and checks for duplicates
3. Approval routing: The invoice is routed to the appropriate department manager for approval based on the amount
4. Final verification: The AP manager confirms payment details match the vendor's file and reviews for any red flags
5. Payment processing: The payment is processed, with secondary approval for high-value transactions. All documentation is archived.

How invoice fraud detection software works

Strong processes are essential, but manual reviews can't catch everything. Invoice fraud detection software adds a critical layer of security that complements your internal controls rather than replacing them.

Automated three-way matching

Software automatically matches invoices to their corresponding purchase orders and receiving documents. Any mismatches in quantities, prices, or item numbers get flagged for human review before payment is made.

AI-powered anomaly detection

Modern fraud detection tools use machine learning to identify unusual patterns a human might miss—sudden changes in a vendor's bank details, atypical invoice amounts, or duplicate invoice numbers. The system gets smarter over time as it learns your company's unique payment patterns.

Real-time fraud alerts

The best software provides instant notifications when suspicious activity is detected. These real-time alerts let you investigate and stop a fraudulent payment before funds leave your account—critical for preventing financial loss.

What to do if you detect invoice fraud

If you discover invoice fraud, act fast to minimize financial impact and strengthen your defenses. Time is the single biggest factor in whether you can recover funds.

• Stop payment immediately: If a suspicious invoice is still pending, place a hold on the payment until verification is complete
• Notify your bank or payment provider: They may be able to reverse or freeze transactions if caught early
• Alert internal teams: Include finance, legal, compliance, and IT to coordinate the investigation and response
• Preserve documentation: Collect all related invoices, emails, approvals, and transaction records to support internal or external investigations
• Report the incident: File a report with the FBI's Internet Crime Complaint Center (IC3) and notify your local law enforcement. Depending on the scale, you may also need to alert regulatory bodies like the FTC.
• Notify affected vendors: If a legitimate vendor's identity was compromised or impersonated, alert them immediately so they can secure their systems and warn other clients
• Contact your insurance provider: Some commercial crime or cyber liability policies cover financial fraud. Understanding your options can help reduce losses.

When invoice fraud hits, every minute counts. Strong accounts payable document management gives you the audit trail you need to recover funds and stop threats before they happen again.

Prevent invoice fraud with Ramp

Ramp Bill Pay is an autonomous AP platform built to stop invoice discrepancies, fraud, and duplicates before they reach payment. Four AI agents work across your invoice workflow—flagging suspicious vendor activity, catching duplicate entries, verifying line items against POs, and auto-coding transactions based on historical patterns. The platform's 99% accurate OCR captures every detail, processing invoices 2.4x faster than legacy AP software1.

Deploy Ramp as a standalone AP solution focused on accuracy and fraud prevention, or connect it with corporate cards, expenses, and procurement for unified spend control. Companies using Ramp report up to 95% improvement in financial visibility2.

Invoice errors slip through when AP teams rely on manual review. Ramp's touchless, autonomous automation catches what finance teams typically miss:

• Four AI agents: Detect fraud, flag duplicates, auto-code transactions, and generate approval summaries with vendor history and pricing context—all before payment goes out
• Fraud prevention agent: Identifies suspicious activity including unexpected banking detail changes, unverified vendor accounts, and questionable email domains
• Intelligent invoice capture: Extracts every line item at 99% OCR accuracy, creating a reliable data foundation for duplicate and discrepancy detection
• Automated PO matching: Verifies invoices against purchase orders with 2-way and 3-way matching to catch overbilling, quantity mismatches, and pricing errors
• Approval agent: Surfaces vendor history, contract terms, PO details, and pricing comparisons—then recommends approval or rejection based on the analysis
• Custom approval workflows: Route invoices through multi-level approval chains with role-based permissions
• Roles and permissions: Enforce separation of duties so no single person can approve and pay without oversight
• Real-time invoice tracking: Monitor every invoice from receipt to payment, with full visibility into where discrepancies were flagged
• Vendor onboarding: Verify vendors upfront by collecting W-9s, matching TINs, and tracking 1099 data in the platform
• Ramp Vendor Network: Pay verified vendors with fewer fraud checks—unverified vendors get flagged automatically
• Vendor Portal: Give vendors a secure channel to update banking details, reducing the risk of payment redirection fraud
• Real-time ERP sync: Connect bidirectionally with NetSuite, QuickBooks, Xero, Sage Intacct, and more to maintain a single source of truth
• Reconciliation: Match transactions automatically to surface duplicates and discrepancies faster during close

Why finance teams trust Ramp

Ramp sets the standard for touchless AP that's accurate, fast, and built to prevent costly mistakes. Use it as a dedicated invoice automation tool or integrate it across your entire spend stack for complete oversight.

G2 reviewers rank Ramp the easiest AP software to use, with a 4.8 out of 5 rating from over 2,100 verified finance professionals. Teams cite fewer errors, faster fraud detection, and simplified reconciliation as top reasons for switching.

Ramp's free tier covers core AP automation. Ramp Plus adds advanced controls at $15 per user per month, with enterprise pricing available on request.

Invoice errors are preventable. Ramp prevents them. Get invoice fraud prevention software that actually works.

Try Ramp for free

1. Based on Ramp’s customer survey collected in May’25