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Duplicate Invoices – Why They Happen and What You Can Do To Prevent Them

6 mins read

Ever paid the same bill twice?Duplicate invoices are a common issue, but these simple mistakes can cost businesses dearly. Let’s explore why duplicate invoices occur (from simple accidents to more malicious motivations) and the steps you can take to avoid invoice fraud in the first place.

What Are Duplicate Invoices?

Excess payments can occur when a business receives the same bill for goods or services more than once. A duplicate invoice could look like an identical copy, have slight variations from the original copy, or be sent through different channels. Anything from a misfired email to a miscommunication on tasks can cause duplicate invoices.Businesses should be on guard because they create financial headaches and inaccurate records. Worst of all, they can potentially cost your company thousands of dollars.

How Do Duplicate Invoices Impact B2B Payments?

The most obvious way inaccurate invoices affect B2B payments is the financial damage they inflict. An industry study discovered that, on average, businesses employing up to 1,000 people experience about six duplicate invoices per month. It also found that the average value of these invoices is about $2,034 — resulting in potential losses of around$12,000 each month if the duplicate invoices were paid out.


That’s not the only negative outcome, either. Trying to identify and resolve duplicates wastes the time and resources of your accounts payable team. Financial statements become distorted, making it difficult to track spending and profitability. And trust might be lost with other vendors if you must delay legitimate payments to fix incorrect ones. All of that assumes duplicates have been detected. If duplicate invoices slip under the radar, your business can get exposed to serious fraud.

Common Causes of Duplicate Invoices

Duplicate invoices can sneak into yourB2B transactions through a variety of unfortunate circumstances. Under standing how and why they happen can help you take appropriate steps to reduce your exposure. Let’s take a closer look at the three most common ways duplicate invoices occur.

Human Error

Good old-fashioned human error is at the top of the list when it comes to duplicate invoice causes. While many workers are well-intentioned, an employee accidentally entering a typo or forgetting to put in critical information could result in a phantom duplicate. It’s extremely easy for a finger to slip and hit an incorrect number or two while typing.


Forgetfulness is another issue—forgetting to mark an invoice as paid or failing to update the system after resolving a discrepancy can lead to the same invoice being entered later. Misinterpreting information on the invoice, like missing a purchase order reference number, is another factor. Sometimes even well-meaning actions can backfire. Someone manually entering an invoice thought to be lost is taking what seems to be the best resolution, but if the original eventually resurfaces, the duplicate will have to be addressed.

Vendor Practices

Vendors can also contribute to duplicate invoices in B2B transactions without even knowing it. Inconsistent payment practices or not following best practices can lead to frequent serious.For example, too many different channels can create an easy point of confusion, such as an invoice coming through both email and snail mail.


Even internal miscommunication can playa role if a canceled invoice isn’t clearly communicated with the appropriate team members. Changes in a vendor’s internal system can unintentionally create havoc, leading to previously paid invoices being re-sent if proper flags aren’t set. On top of that, some vendors may not have stringent internal controls, making an environment ripe for duplicate invoices.

Bad Actors

Unfortunately, the other common cause of duplicate invoices is malicious intention. Sometimes duplicates are created intentionally to scam a company out of money. That could look as simple as tweaking the amount on a legitimate invoice or as complex as creating shell vendors that don’t exist.


Fraudsters take advantage of disorganization and inconsistent practices by creating near-identical copies of real invoices that slip past undetected. These fakes often have only the slightest variations in dates, banking details, or invoice numbers to escape notice. Bad actors may also alter legitimate invoices and manipulate quantities to inflate the amount due. In some of the most devastating cases, a dishonest employee within the company collaborates with a vendor to process fraudulent duplicate invoices.

Business Risks of Duplicate Invoices inB2B Payment Flows

What kind of risk can duplicate invoices introduce to B2B payment flows? There are three primary risks:

Financial Losses

Financial loss might be an obvious consequence of duplicate invoices, but it’s still one of the most harmful. The most direct risk is paying the same bill twice. Not only does that take a hit on a company’s funds, but it also strains cash flow and impacts on the ability to meet other financial obligations. To investigate and resolve duplicate invoices, the company will also likely have to invest in costly tools and manpower.

Fraud Schemes

Duplicate invoices make it easier for fraudsters to get inside your B2B payment transactions and wreak havoc. For example, if an attacker can access just one employee account, they can message all your clients and vendors with new payment details and fake invoices. They can even impersonate legitimate vendors to send invoices that seem valid at first glance. These are especially hard to detect, making it easy for attackers to send multiple duplicates. Fraud schemes also come in the form of actual vendors who maliciously inflate payment amounts or send duplicate invoices in the hopes that busy teams won’t notice.

Operational Inefficiency

Operational inefficiency is another serious risk that duplicate invoices bring into B2B payment flows. Finding and addressing duplicates is almost always time-consuming and diverts accounts payable staff away from their core tasks, resulting in backlogs and delays in processing valid invoices. Duplicate invoices create confusion within the company’s system as well. This makes it difficult to track spending patterns and distorts the company's financial records, making effective cash flow management challenging.

Best Practices for Duplicate InvoicePrevention

Although duplicate invoices are a common problem, there are steps you can take to make sure they don’t happen.Here are two of the best ways to create an environment inhospitable to duplicates:

Invoice Management Solutions

Invoice management solutions act as a shield against duplicate invoices by automatically checking for duplicates. They accomplish this by taking invoice data and matching it against existing records, purchase orders, and past payments. This removes both the burden of manual data entry and the risk of human error that comes with manual inputs.  

Standardized Internal Processes

Automated solutions are only as powerful as your standardized internal processes. Without company-wide procedures, duplicate invoices are a matter of when, not if. Clear guidelines for invoice handling — from receiving to approval — help maintain consistency and minimize the chance for errors. This might look like setting designated channels for invoice submission and requiring proper flagging of corrected or canceled invoices.

Common Methods for Duplicate InvoiceDetection

Catching incorrect and replicated invoices is the easiest way to avoid costly payment errors. There are two common ways that you can utilize invoice fraud detection:

Manual Review

You can manually comb through invoices to look for inconsistencies or suspicious details. This could look like verifying invoice data against purchase orders and spotting discrepancies in vendor information or product descriptions. However, manual review is extremely time-consuming.

Automated Solutions

Alternatively, automated solutions offer a powerful first line of defense against duplicate invoices. They can leverage algorithms to analyze invoice data and compare it to existing data.Not only can they flag exact duplicates, but they can also detect trickier copies that use the slightest of variations to appear as close to the original copy as possible.

3 Technologies to Help You Detect Duplicate Invoices

While manual review will likely remain a part of duplicate invoice detection for some years to come, automated solutions help expedite the processing cycle and reduce the overall manual workload. Here are three technologies that can help you detect invoice fraud more easily:

AI and Machine Learning

Artificial intelligence (AI) and machine learning are incredible tools that can be utilized for tremendous good. Perhaps their most advantageous feature is that they can learn and adapt overtime, keeping up with the evolving tactics of fraudsters and becoming more adept at spotting even the most cleverly disguised duplicates. The more invoice data that AI-powered tools receive, the easier it is for them to recognize patterns and anomalies that might escape more rigid rule-based systems. This lets your company take a proactive approach to potential invoice fraud rather than simply a defensive one.

System Integrations

System integrations, or fostering communication between all your different platforms, is another key step to catching duplicate invoices before they even begin. When you connect your accounts payable system with other information sources like purchasing databases, invoice data can automatically be cross-checked for matches. System integrations can also help facilitate real-time verification of purchase orders to confirm that invoices correspond with authorized purchases.

Real-time Monitoring and ActiveAlerts

Speaking of real-time verification, real-time monitoring and active alerts lets you respond immediately even if a duplicate invoice slips past your first few barriers. These systems continuously scan incoming invoices and trigger instant notifications when potential duplicates are detected. That way, your accounts payable team can resolve the issue as quickly as possible, preventing any further delays or loss.


Prevent Duplicate Invoices with Trustmi

If you’re currently struggling with duplicate invoices popping up in your B2B payments, then Trustmi offers the most comprehensive protection against these costly issues. We use advanced AI to detect abnormal payment activities, and we also provide real-time risk assessment on all your organization’s payments. On top of that, we offer our unique Trust Network, uniting powerful crowd-sourced data across thousands of vendors and businesses to maximize protection for business payments.


Don’t wait any longer. Stop duplicate invoices in their tracks and schedule a demo of Trustmi with one of our experts today.