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How to Spot Altered Checks and Prevent Costly Fraud

Written by VALID Systems | May 23, 2025 1:05:32 PM

Knowing how to spot altered checks is critical for anyone handling financial transactions, because paper checks are still around despite the rise of digital payments.

While checks may seem outdated, fraudsters find new, increasingly subtle ways to exploit them.

This guide breaks down the tactics used by fraudsters, the red flags you need to watch for, and the tools that leading financial institutions are using to stop altered checks before they clear and prevent costly fraud before it happens.

What is an altered check?

An altered check is a real check that has been fraudulently modified after it was issued. Common alterations include changing the check amount or the payee's name to redirect funds or increase the payout.

Imagine your financial institution processes hundreds of checks every day. One of them is issued for $1,000. A few weeks later, you discover that the same check was used to withdraw $10,000.

Somehow, someone altered the check, throwing off your entire financial record.

An altered check is simply a real check that's been tampered with by someone other than the original writer. The most common tricks include changing the amount, like adding an extra zero or altering the payee's name.

How altered checks differ from counterfeit checks

It's a type of check fraud in which the check begins as legitimate but gets hijacked and changed after it's written. This differs from counterfeit checks, which are entirely fake from the start.

Altered checks can easily go undetected, especially when someone makes changes that blend in with the original writing.

The tricky part is that these checks still look real at first glance and are more difficult to detect.

According to the Uniform Commercial Code (UCC) Section 3-407, liability can fall on various parties: 

  • the check writer, 
  • the bank that cashed it, 
  • or the bank that presented it for payment.

The longer you wait to spot the fraud, the harder it is to recover your funds.

How to spot altered checks: 12 critical signs to watch for

Every check contains critical details, but altered checks often leave subtle red flags that can go unnoticed.

Here's how to identify those warning signs and protect yourself from fraud:

1. Inconsistent handwriting and fonts

If the handwriting or fonts differ between check sections, especially between the payee name, the amount, or the date, it suggests tampering. Fraudsters often use different writing styles or fonts to change details.

How to spot it:

Compare the handwriting or font used in the payee name and the amount fields. If they don't match, it's worth questioning. Pay attention to variations in slant, size, and neatness between fields.

2. Visible erasure or overwriting

Fraudsters frequently use erasers, correction fluid, or chemicals to alter the check's details. You might notice faint marks, smudging, or blurry or faded areas.

How to spot it: 

Hold the check up to the light. When you spot ghost images, traces of previous writing, or uneven ink, you're likely looking at an altered check.

3. Ink and color discrepancies

If the check uses different ink colors or pens in various fields, it's a sign of tampering. A common trick is using one color for the amount and a different one for the payee's name.

How to spot it: 

Look for inconsistencies in the ink's thickness, sheen, or color. If the ink in one area looks newer or shinier than the rest of the check, it's worth investigating.

4. Unusual spacing or alignment

Fraudsters need space to alter checks. The check might have been tampered with if there are large blank spaces after the payee's name or amount, or if the text is misaligned or squeezed in.

How to spot it: 

Check the spacing between text fields. If the alignment feels off or there's huge empty space, it could be a sign that someone added or altered text after the check was written.

5. Discrepancies in amounts

This is a major indicator if the written amount doesn't match the numerical amount or if one seems altered. Fraudsters often change either the number written in words or the numeric value to inflate the check's worth.

How to spot it: 

Always compare the written amount (in words) with the numerical amount. If they don't match exactly or one seems off, investigate further.

6. Missing or tampered security features

Modern checks include watermarks, microprinting, and security threads to prevent fraud. The check may have been tampered with if these features are missing, faded, or altered.

How to spot it: 

Hold the check up to a light to see if any watermarks appear. Check for microprinting and security threads embedded in the check. If they're missing or look faded, it's a red flag.

7. Unusual paper quality

Banks and legitimate issuers print authentic checks on thick, high-quality paper that resists wear and tear. However, it could signify fraud if the paper feels flimsy, cheap, or inconsistent with other checks.

How to spot it: 

Compare the check's paper quality with others you've written. It may be altered or counterfeit if it feels thin, is textured differently, or is unusually soft.

8. MICR line and check number mismatches

The Magnetic Ink Character Recognition (MICR) line containing routing and account numbers should match the check number at the top right corner. A mismatch often signals that someone has altered the check.

How to spot it: 

Pay close attention to the MICR line at the bottom of the check. If the numbers don't align with the check number in the top right corner, it's likely an altered check.

9. Blurry or pixelated logos

Blurry or pixelated logos often indicate that someone used low-quality printing equipment. These distortions commonly appear on checks that have been digitally altered or photocopied.

How to Spot it: 

Inspect the logos and images on the check closely. It could be a counterfeit or altered check if they look fuzzy or pixelated, or if the printing seems uneven.

10. Mismatched check numbers

Fraudsters may insert fake checks into a sequence, causing sudden gaps or jumps in check numbers. Such irregularities often point to an attempt to disguise alterations.

How to Spot it: 

Check the numbering sequence. If there's an unusual gap between checks or a sudden drop in numbers, ask your bank to verify the sequence and investigate further.

11. Suspicious endorsements

Mismatched or forged endorsements often signal that someone has altered the check. Fraudsters usually generate signatures to cash altered checks.

How to Spot it: 

Compare the endorsement on the back of the check with previous signatures from the payee. If the signature doesn't match or seems unusual, it's likely forged.

12. Concealed checks in bulk

In business settings, fraudsters may hide altered checks among legitimate ones, hoping they'll be signed without proper inspection.

How to Spot it: 

When signing checks in bulk, take extra care. Review each one thoroughly, especially if they were received or processed quickly. Don't sign checks without double-checking their details, even if it's a routine process.

8 Proven ways to prevent altered check fraud

Preventing altered check fraud is key to protecting your finances. Here's how to stay secure and safeguard your financial interests:

1. Implement advanced fraud detection systems

AI and machine learning systems can analyze and check transactions and detect even the most minor alterations that might go unnoticed. These tools allow real-time detection, helping to prevent fraudulent checks before they're processed.

Action steps:

  • Use AI-powered systems for analyzing check images.
  • Set up real-time alerts for any suspicious check transactions.

2. Invest in employee training

Regular training helps employees recognize altered checks and fraud schemes. Staff with up-to-date knowledge are better prepared to spot tampering or other signs of fraud.

Action steps:

  • Conduct regular training on fraud detection methods.
  • Use real-life simulations to improve staff readiness in spotting altered checks.

Tip: Conducting phishing simulations helps staff recognize fraudulent attempts and respond effectively. These exercises mimic real-world scenarios, giving employees the experience to spot and handle fraud.

3. Use high-security checks

High-security checks include features like watermarks, microprinting, and chemical-sensitive paper, making alterations more visible. These checks are difficult to replicate and offer a strong deterrent against fraud.

Action steps:

  • Choose checks with advanced security features.
  • Regularly update checks to stay ahead of fraudsters.

Tip: Recommended update frequency for high-security checks:

  • Annually: Review and update checks yearly.
  • After Changes: Update checks after major operational changes.
  • Emerging Threats: Adjust checks based on new fraud trends.

4. Implement real-time decisioning for check deposits

Real-time decision-making systems allow financial institutions to approve or reject checks based on specific criteria instantly. This reduces the chance of fraudulent checks clearing unnoticed.

Action steps:

  • Implement systems that approve or reject checks instantly.
  • Notify customers immediately when a check is flagged or rejected.

Pro Tip: VALID Systems’ Real-Time Loss Alerts (RTLA) enable sub-second fraud detection for check deposits. By flagging altered or suspicious items across all channels, RTLA helps institutions reduce processing time, stop fraud early, and protect customers without slowing down legitimate transactions.

5. Monitor transactions continuously

Continuous transaction monitoring detects suspicious activity early and enables swift action to prevent losses. It also reveals unusual patterns that may indicate fraud.

Action steps:

  • Set up continuous transaction monitoring for all checks.
  • Use real-time alerts to notify staff of any discrepancies.

6. Educate customers on fraud prevention

Educating customers on recognizing altered checks and reporting suspicious activities can significantly reduce the likelihood of fraud. Customers play a vital role in fraud prevention.

Action steps:

  • Offer educational resources on fraud prevention to customers.
  • Encourage customers to report suspicious checks promptly.

7. Store checks securely

Secure storage of blank and signed checks prevents tampering or theft. Keeping checks in a locked location reduces the risk of unauthorized access and fraud.

Action steps:

  • Store checks in locked, secure locations.
  • Limit access to checks to authorized personnel only.

8. Review bank statements regularly

Reviewing bank statements frequently helps individuals and businesses quickly spot discrepancies and take action before significant damage occurs.

Action steps:

  • Review bank statements at least once a month for any unauthorized transactions.
  • Set up alerts for large or unusual transactions.

How can Valid Systems help you prevent altered check fraud?

Valid Systems is a leading provider of AI-driven fraud prevention solutions designed to combat evolving check fraud threats, including altered check fraud.

Leading financial institutions like PNC, TD Bank, and Truist trust Valid Systems for a reason.

With over two decades of experience, Valid blends deep industry knowledge with cutting-edge AI technology to prevent fraud that keeps pace with evolving threats.

Through seamless integration and real-time insights, Valid enables your organization to act swiftly, reduce risks, and maintain customer trust.

A closer look at our most trusted tools.

RTLA© (Real-Time Loss Alerts) - Early fraud interception

Real-Time Loss Alerts (RTLA©) identify up to 75% of check deposit charge-offs at the point of presentment. This allows banks to stop altered check fraud before releasing funds, minimizing losses and operational disruption.

INclearing Loss Alerts - Detection beyond traditional systems

INclearing Loss Alerts utilize machine learning to uncover fraud patterns that other systems miss. This approach is especially practical for detecting sophisticated alterations.

VALID Edge Check Data Consortium - Predictive protection at scale

The VALID Edge Check Data Consortium offers access to data from over 420 million accounts and $6 trillion in processed checks annually. Such a vast, anonymized data network allows predictive fraud detection by identifying patterns typical of altered check attempts.

Do you want to know how to spot altered checks and avoid check fraud?

Book your free consultation with Valid Systems to learn how our advanced technology can help you prevent altered check fraud before it starts.