What is Vendor Bank Account Verification?

Vendor bank account verification is the process of confirming that a supplier's bank account details — routing number, account number, and account holder name — are accurate and belong to the entity you intend to pay. It's the last line of defense between your AP team and sending money to the wrong account.

The stakes are not small. The FBI's Internet Crime Complaint Center reported $2.9 billion in losses from business email compromise in 2023 alone, with a significant share involving fraudulent bank detail changes. Once a wire or ACH payment lands in the wrong account, recovery rates sit below 30%.

How Vendor Bank Account Verification Works

The process starts when your AP team receives bank account information — either during vendor onboarding or when an existing vendor requests a change to their payment details.

First, your team collects the banking information: bank name, routing number (ABA for domestic, SWIFT/BIC for international), account number, and the account holder's legal name. This data comes from the vendor directly, ideally through a secure portal rather than email.

Next, your team verifies that the account exists and belongs to the vendor. This is where methods differ — from sending micro-deposits and confirming the amounts, to using third-party validation services that check account ownership in real time, to the old-fashioned approach of calling the vendor at a known phone number.

Finally, the verified details are locked into your vendor master file. Any future change request triggers the entire verification cycle again — no exceptions.

Verification Methods Compared

Method	How It Works	Speed	Reliability	Cost
Micro-deposits	Send two small deposits (under $1), vendor confirms amounts	2-3 business days	High — proves account access	Low ($0.50-2 per verification)
Third-party validation (Plaid, Giact, Early Warning)	API call checks account ownership against bank records	Seconds to minutes	Very high — direct bank data	Medium ($1-5 per check)
Manual callback	Call vendor at a pre-verified phone number to confirm details	Hours to days	Moderate — depends on reaching the right person	Low (staff time only)
Bank letter or voided check	Vendor provides official bank documentation	Days to weeks	Moderate — documents can be forged	Low (staff time only)

Third-party validation services offer the best balance of speed and accuracy. Micro-deposits remain solid for organizations that want verification without subscription costs. Manual callbacks work as a secondary check but should never be your only method.

Vendor Bank Account Verification Examples

Example 1: New Vendor Onboarding

Your company signs a contract with a new IT consulting firm. During vendor onboarding, the firm submits their W-9 and banking details through your vendor portal. Before the first invoice is even received, your AP team runs the account through a third-party validation service. The check confirms the account holder name matches the legal entity on the contract. The vendor record is created with verified banking data, and the first payment processes without risk.

Example 2: Bank Detail Change Request via Email

This is the scenario that costs companies millions. Your AP clerk receives an email from what appears to be a long-standing vendor's CFO: "We've switched banks. Please update our payment details to this new account." The email looks legitimate — correct logo, correct formatting, even references a real invoice number.

This is a classic BEC attack. The attacker has either compromised the vendor's email or created a convincing spoof. Without a verification protocol, the next payment goes to the attacker's account.

The fix: every bank detail change triggers a mandatory callback to the vendor using a phone number already on file (not the number in the email). A third-party validation check confirms the new account. Two people in AP must approve the change — segregation of duties prevents a single person from redirecting payments.

When to Verify Vendor Bank Details

Run verification when:

• New vendor setup — before the first payment ever leaves your account
• Bank detail change requests — the highest-risk moment in AP
• First payment to a vendor — even if the vendor was set up months ago
• After a period of inactivity — if you haven't paid a vendor in 6+ months, re-verify before resuming
• International payments — higher risk and harder to recover, so verification is non-negotiable

Key Takeaways

• Definition: Vendor bank account verification confirms a supplier's bank details are legitimate and belong to the entity you intend to pay
• Purpose: Prevent payment fraud, especially BEC attacks that redirect payments by changing bank details
• Best for: Any AP team processing payments — the cost of verification is a fraction of the cost of a single misdirected payment

Related Terms

• Vendor Onboarding — the full process of setting up a new supplier, where bank verification is a critical step
• Three-Way Matching — verifying invoice details against PO and receipt before payment
• Payment Reconciliation — matching outgoing payments against invoices and bank statements after payment