What duplicate and fraudulent invoice payments look like in financial services
A duplicate payment is any disbursement that pays the same supplier obligation more than once, and a fraudulent payment is one made against an invoice or bank account that the real supplier never issued.
Financial services firms buy a lot of recurring services: core banking licenses, credit bureau data, collections agencies, legal panels, branch facilities and cloud hosting. Many of these suppliers bill monthly, send invoices to more than one address, and upload the same PDF to a supplier portal. Research cited by the Washington State Auditor puts duplicate payments at 0.8% to 2% of total payments made.[1] On a large payables book, that is real money leaving through a control gap.
A typical case looks ordinary. A legal firm emails its monthly invoice to the AP inbox and copies the general counsel, who forwards it to AP again a week later with "please pay, overdue." One copy is keyed as INV-1042 and the other as 1042, under a second vendor record created during an entity migration. Both clear. Fraud follows the same path: a convincing email announces new remittance details for a known vendor, and the next payment goes to the wrong account. Payments fraud remains common: 76% of US organizations experienced attempted or actual payments fraud in 2025.[2]
AP Manager
Owns the payment run but receives invoices through email, portals, forwards from business owners and paper at the branch.
"I can't prove this isn't already in the system."Financial Controller
Finds duplicates only at month-end reconciliation or when a supplier statement shows a credit balance.
"Why does this vendor owe us money?"CFO
Has to explain payment control failures to the audit committee and, in a regulated entity, to supervisors.
"How many of these did we not catch?"Internal Audit or Risk
Needs evidence that segregation of duties and bank detail verification actually happened, not just that a policy exists.
"Show me who approved the account change."Are duplicate or fraudulent payments getting through in your AP process?
Tick every statement that is true today. Three or more means the problem is likely costing you real money.
Six root causes behind paying an invoice twice
Duplicates and fraud share the same weak points. Fix these and both fall together.
Too many ways for an invoice to arrive
An AP inbox, a portal, forwards from business owners and paper at branches all feed the same queue. Each channel is a chance to key the same invoice again.
Duplicate vendor records
Mergers, new legal entities and rushed onboarding create a second record for the same supplier. Most system checks only compare invoices within one vendor ID, so the duplicate slips past.
Exact-match duplicate checks
A check on vendor plus invoice number misses "INV-1042" versus "1042", swapped digits, or a different invoice date. Keying variation beats rigid rules.
No link between invoice, PO and receipt
Service invoices in financial services often have no PO at all. Without a PO to consume, nothing stops the same monthly charge being approved twice.
Weak control over bank detail changes
When a remittance change arrives by email and the person who updates the vendor record also releases payments, one convincing message is enough to redirect funds.
Suppliers resubmit when they hear nothing
If suppliers cannot see payment status, they resend invoices and chase business owners, who forward them to AP. Silence creates duplicates.
What duplicate and fraudulent payments cost a financial services firm
Published research shows both problems are common enough to treat as a standing risk rather than an occasional error.
The direct cost is the cash itself. Some duplicates come back when a supplier notices, some sit as credits you never use, and fraudulent payments are often gone for good once funds leave the recipient bank. The indirect costs build on top: AP and treasury time spent chasing refunds, recovery audit fees, write-offs, and in a regulated firm, audit findings on payment controls that take months of remediation work to close.
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The expert playbook: six controls that stop paying twice
These controls work in any AP setup. Start at intake and the vendor master, because every later check depends on clean inputs.
"When I worked on the Ariba Network at SAP, the pattern was clear. Duplicates are rarely one careless clerk. They come from a process with three doors in and no memory of what already came through. In banks, auditors then ask for proof. Give every invoice one door, tie it to a PO or contract, and the proof builds itself."Md. Kafil, Co-founder and CEO, Zapro. Former senior product specialist on SAP Ariba Network and procurement transformation manager at KPMG.
Close every invoice side door
Deduplicate and lock the vendor master
Match invoices to a PO, contract or receipt
Verify every bank detail change out of band
Run fuzzy duplicate checks before each payment run
Give suppliers payment status
"At Voonik we had 5,000 to 6,000 active suppliers emailing invoices into one inbox and calling to ask where their payment was. Every unanswered call became a resent invoice. What cut duplicates was not a stricter clerk. It was letting suppliers see status themselves. When the supplier knows the invoice is approved, they stop sending it again."Daniel Sagayaraj, Co-founder and CTO, Zapro. Previously built and ran supplier onboarding and payments for a 15,000-supplier marketplace at Voonik.
How Zapro closes the gaps that let invoices get paid twice
Zapro puts intake, vendor records, POs, contracts and invoice matching in one workflow, so an invoice has to fit a known supplier and a known obligation before it can be paid.
| Root cause | Zapro capability | What changes |
|---|---|---|
| Too many intake channels | AP Automation: automatic invoice capture and data extraction | Invoices from email, API or SFTP land in one queue, so AP sees every copy in one place instead of across inboxes and forwards. |
| Duplicate vendor records and weak bank detail control | Vendor Management: centralized vendor profiles and compliance monitoring | One profile per supplier holds documents and details, and role permissions limit who can change them. |
| No link between invoice, PO and receipt | AP Automation: two-way and three-way matching with exception handling | Invoices must match a PO and receipt, and mismatches go to an exception queue instead of the payment run. |
| Recurring service invoices with no reference | Procurement: purchase requests, approvals and POs | Recurring services get a PO up front, so each monthly invoice consumes a known line once. |
| Suppliers resubmit when they hear nothing | Integrations: payment status sync with ERP and accounting | Payment status flows back from your ledger, so AP can answer where an invoice is without anyone resending it. |
Zapro keeps vendor and master data in two-way sync with your ERP or accounting system, with legal entities and accounts aligned, and receives invoices via API or SFTP. See Zapro integrations and Zapro for Financial Services.
A 30, 60, 90 day plan
Days 1 to 30: Find the leaks
- Run a duplicate review on 12 to 18 months of payments
- List every invoice intake channel in use
- Identify vendor records sharing tax IDs or bank accounts
- Map who can change bank details and who releases payments
Days 31 to 60: Close the doors
- Announce one invoice channel to all suppliers
- Merge or block duplicate vendor records
- Introduce callback verification with a second approver
- Start PO or contract matching for the top 50 suppliers
Days 61 to 90: Make it routine
- Run fuzzy duplicate checks before every payment run
- Extend matching to all recurring service suppliers
- Share payment status with suppliers
- Report duplicates caught and recovered to the audit committee
KPIs to track progress
| KPI | How to calculate | Review |
|---|---|---|
| Duplicate payment rate | Value of confirmed duplicate payments divided by total payments made | Quarterly |
| Duplicates caught before payment | Confirmed duplicates stopped before release divided by all confirmed duplicates | Monthly |
| Single-channel intake rate | Invoices received through the approved channel divided by all invoices | Monthly |
| Duplicate vendor records | Active vendor records sharing a tax ID or bank account | Monthly |
| Verified bank detail changes | Changes verified by callback and second approver divided by all changes | Monthly |
| Matched invoice rate | Invoice value matched to a PO or contract before approval divided by total invoice value | Monthly |
Go deeper with our guide to accounts payable automation guide.
What a Zapro customer saw after moving this work into one workflow
"Implementing Zapro improved our vendor coordination significantly, leading to a substantial reduction in costs and faster vendor onboarding."Akhil Sikri, CTO, Zolo
Why Zapro for this challenge
Duplicate and fraudulent payments get through when an invoice can reach payment without proving which supplier and which obligation it belongs to. Zapro makes that proof part of the workflow, so the check happens every time instead of at audit.
The vendor record is the anchor
Invoices, POs, contracts and documents hang off one supplier profile, which makes a second record or a changed bank account stand out.
Z1 reads and matches every invoice
Zapro's AI layer reads incoming invoices, matches them to POs and receipts, and flags risk before approval rather than after payment.
Audit trail built in
Every approval and change is logged with granular role permissions, which gives auditors and supervisors the evidence they ask for.
Security suited to regulated firms
AES-256 encryption, WAF, DDoS protection and GDPR-aligned practices, with SSO tied to your identity systems.
When Zapro may not be the right fit
- You pay a small number of suppliers from one entity and a monthly manual review already catches every duplicate.
- You need a dedicated payment execution or bank account validation service. Zapro manages invoices and approvals and syncs payment status, and works alongside your bank and treasury tools.
- Your core problem is card or wire fraud on customer accounts rather than supplier payments. That calls for transaction fraud systems, not procure-to-pay software.
Frequently asked questions
What causes duplicate invoice payments?
Most duplicates come from the same invoice arriving through more than one channel, the same supplier existing under two vendor records, or a duplicate check that only blocks exact matches on invoice number. Suppliers resending invoices because they cannot see payment status adds to the problem.
How do you detect duplicate payments that have already happened?
Pull 12 to 18 months of paid invoices and compare them on normalized invoice number, amount, invoice date within a short window, and vendor tax ID or bank account rather than vendor ID alone. Confirm each hit against the supplier statement before requesting a refund.
What is the best control against vendor bank detail fraud?
Verify every change by calling the supplier on a number you already hold, require a second person to approve the change, and review the first payment to new details before release. Do not act on contact details supplied in the change request itself.
Is an ERP duplicate check enough?
Usually not on its own. Most built-in checks compare vendor ID and invoice number exactly, so a different vendor record or a small keying difference passes. Combine it with a clean vendor master, PO or contract matching and a fuzzy check before each payment run.
How does software help prevent duplicate payments?
Software helps by capturing invoices in one place, matching them to POs and receipts, and holding mismatches before approval. Tools such as Zapro also keep vendor profiles and bank details under role-based control with an audit trail, which addresses the fraud side as well as keying errors.
About the experts behind this page
Sources
- Office of the Washington State Auditor, Paying vendors twice is a problem: SAO offers tips to prevent duplicate payments, 2022
- Association for Financial Professionals, 2026 AFP Payments Fraud and Control Survey press release: Over 75% of US Firms Experienced Payments Fraud in 2025, 2026
Editorial note: this page is published by Zapro, which sells procurement software. Best practices are written to work with any tool, and figures are cited to their original publishers. Last reviewed 29 September 2026; next review due March 2027. See how the Procurement Challenges Directory is researched and reviewed.