Suspicious Transaction Reports (STR) in Nigeria: When and How to File

A suspicious transaction report is filed when a bank, fintech, or other reporting entity identifies a transaction or activity that gives reasonable grounds for suspicion of money laundering, terrorism financing, or a predicate offence.

In Nigeria, the report is submitted to the Nigerian Financial Intelligence Unit (NFIU). The important point is that an STR is suspicion-based, not simply based on transaction value. There is no minimum transaction amount for filing an STR. 

This guide explains what an STR is, when it should be filed, the 24-hour reporting rule, how to file an STR, what the report should contain, common mistakes, and how transaction monitoring can support the process.

What Is a Suspicious Transaction Report in Nigeria?

A suspicious transaction report in Nigeria is a formal report submitted to the NFIU when a reporting entity identifies a transaction that meets the legal criteria for suspicion.

Under Section 7 of the Money Laundering (Prevention and Prohibition) Act 2022, a transaction may be considered suspicious where, for example, its frequency is unreasonable, it has unusual or unjustified complexity, appears to have no economic justification or lawful purpose, is inconsistent with the known pattern of the account or business relationship, or appears to involve proceeds of criminal activity, money laundering or terrorist financing.

The NFIU's current guidance also explains that suspicious activity can be identified through red flags arising from facts, behaviours, patterns or other factors that are inconsistent with what the reporting entity knows about its customer and their expected transaction activity. 

What is STR meaning in banking?

STR meaning in banking refers to the process of reporting a transaction or activity that a bank or other reporting entity has reasonable grounds to suspect may be connected to financial crime.

Banks, fintechs and other reporting entities do not need to prove that a crime has occurred before filing a suspicious transaction report. The purpose of the NFIU STR is to provide financial intelligence to the NFIU for analysis.

The NFIU states that an STR does not mean the person reported is guilty of a crime. Criminal liability can only be determined by a court. 

The NFIU receives and analyses these reports and may generate intelligence for relevant law enforcement agencies or refer regulatory and administrative issues to appropriate authorities.

For a broader explanation of suspicious transaction reporting, see our guide to suspicious transaction reporting.

When Must a Bank or Fintech File an STR in Nigeria?

A bank or fintech should file a suspicious transaction report in Nigeria when its review establishes reasonable grounds to suspect that a transaction or activity may be connected to money laundering, terrorism financing, or a predicate offence.

The trigger is therefore suspicion, not simply the size of the transaction.

Some situations that may lead to an NFIU STR include:

• Transactions that are inconsistent with a customer's known profile or normal activity.

• Unusual or unnecessarily complex transaction patterns.

• Transactions that appear to have no clear economic or lawful purpose.

• Patterns that may indicate structuring or attempts to avoid controls.

• Activity that appears connected to proceeds of crime.

• Suspicious attempted transactions, even where the transaction is not completed.

• Information from KYC, customer due diligence or transaction monitoring that creates reasonable grounds for suspicion.

Section 7 of the MLPPA 2022 specifically states that the reporting obligation applies whether the transaction is completed or not.

An alert does not automatically mean an STR should be filed

This distinction is important.

A transaction monitoring system may flag an activity because it matches a particular rule or red flag. That alert should then be investigated to determine whether the circumstances actually establish suspicion.

The NFIU's financial institution guidance recognises that transaction monitoring systems can generate alerts that ultimately do not qualify as suspicious. It recommends that institutions document alerts that were investigated but did not result in an STR, including the reasons for the decision. 

So the process should be:

Transaction → Alert → Investigation → Suspicion established → STR

Not:

Transaction → Alert → Automatic STR

Is there a minimum amount for an STR?

No.

The NFIU states that STRs must be filed for suspicious transactions regardless of value. This means a relatively small transaction can require an NFIU STR if its circumstances are suspicious, while a large transaction does not automatically become an STR simply because of its value. 

This is one of the main differences between an STR and a Currency Transaction Report, which is threshold-based.

READ on AML Regulations in Nigeria and What Banks and Fintechs must do

What Is the Deadline for Filing an STR in Nigeria?

The 24-hour rule is clearly supported by both the Money Laundering (Prevention and Prohibition) Act 2022 and current NFIU guidance.

Section 7(2) of the MLPPA 2022 requires a financial institution or designated non-financial business and profession to report a suspicious transaction to the NFIU within 24 hours after the transaction identified under the suspicious transaction provisions. The Act also requires the reporting entity to prepare a written report containing the relevant information, reasons for suspicion and identities of the principal and, where applicable, beneficiaries. 

The NFIU's current FAQ similarly states that reporting entities must file STRs immediately and no later than 24 hours after establishing reasons for suspicion. 

The NFIU's financial institution guidance provides additional context on how institutions form suspicion. It states that the transaction should undergo a thorough examination and screening process, with the 24-hour reporting period activated once the transaction is determined to meet the criteria for suspicion. 

For practical compliance purposes, this means institutions should not wait until the reporting deadline before starting their investigation. Alerts need to move quickly through review, investigation, decision-making and reporting.

How to File an STR in Nigeria: Step-by-Step Guide

Knowing How to file STR correctly involves more than completing a form. The institution needs to identify the suspicious activity, investigate it, document the basis for suspicion and submit the report through the appropriate reporting channel.

For financial institutions, the NFIU states that STRs are filed through goAML, its web-based reporting system. Registration is required before using the platform.

Here is a practical How to file STR process.

Step 1: Identify the potentially suspicious activity

Start with the activity that triggered the concern.

This could be a transaction monitoring alert, unusual customer behaviour, a KYC concern, a transaction pattern or information obtained during customer due diligence.

At this stage, an alert is a signal for investigation. It is not yet a conclusion that an STR should be filed.

Step 2: Investigate the transaction and customer

Review the information necessary to understand the activity in context.

This may include:

• Customer identification and KYC information

• Customer risk profile

• Expected transaction behaviour

• Relevant transaction history

• Related accounts and counterparties

• Previous alerts or investigations

• Source of funds information where relevant

• Other relevant red flags

The goal is to determine whether the activity has a reasonable explanation or whether the available information establishes grounds for suspicion.

Step 3: Determine whether an STR is required

Once the investigation is complete, the compliance team should determine whether the circumstances meet the criteria for an NFIU STR.

This is where professional judgement matters.

Not every unusual transaction is suspicious, and not every transaction monitoring alert should result in a suspicious transaction report.

The institution should also document alerts that were investigated but did not qualify for reporting, including the reason for the decision. The NFIU guidance specifically recommends this approach. 

Step 4: Prepare the STR and explain the reason for reporting

Once suspicion has been established, prepare the report with enough information for the NFIU to understand what happened and why the institution considers it suspicious.

The MLPPA 2022 requires the written report to contain relevant information about the suspicious transaction, the reasons for the suspicion and the identities of the relevant parties. 

A useful STR narrative should clearly explain:

• Who is involved?

• What happened?

• When did it happen?

• Where did it happen?

• Why is it suspicious?

• How did the activity occur?

The NFIU guidance specifically requires reporting entities to explain the grounds for suspicion and how the facts, context and relevant ML/TF/PF indicators led to the conclusion. 

What information should a suspicious transaction report contain?

The exact fields depend on the applicable reporting platform, but an NFIU STR should provide enough information to identify the parties, understand the relevant transactions and explain the basis for suspicion.

The narrative is particularly important. A list of transactions alone does not explain why they are suspicious. The report should connect the transactions and other relevant facts to the institution's reason for reporting.

Step 5: Submit the STR through goAML

For financial institutions, the NFIU states that goAML is the web-based system used for How to file STR submissions. 

Once submitted, the NFIU provides acknowledgement through the goAML Message Board, with email notifications also sent to registered users. 

Step 6: Keep the investigation and reporting record

Filing the suspicious transaction report is not the end of the compliance process.

The institution should retain the information supporting the investigation, decision and filing. This creates an audit trail showing what was identified, what was reviewed, why the activity was considered suspicious and what was ultimately reported.

A connected record also makes it easier to respond if additional information is later required.

Common Mistakes When Filing an STR in Nigeria

Understanding How to file STR is important, but the quality of the process matters just as much.

1. Treating every alert as an STR

A transaction monitoring alert is an indication that something requires review. It does not automatically establish suspicion. Investigate the alert and document the outcome before deciding whether to file an NFIU STR. 

2. Filing because of the transaction amount alone

A large transaction is not automatically a suspicious transaction report.

The NFIU confirms that STR reporting is not threshold-based. The circumstances surrounding the activity determine whether it is suspicious. 

3. Writing a weak narrative

A report should explain the reason for suspicion rather than simply list transactions. The NFIU guidance requires reporting entities to articulate how the facts, context and relevant indicators led to reasonable grounds for suspicion. 

4. Looking at only one transaction

Suspicious behaviour may become clear only when several transactions, accounts, counterparties or customer activities are reviewed together.

The investigation should therefore consider the relevant pattern rather than focusing only on the transaction that initially triggered the alert.

5. Losing the investigation trail

If the alert, investigation notes, evidence and suspicious transaction report are stored in separate systems, it can become difficult to demonstrate how the final reporting decision was reached.

A connected case and reporting workflow helps preserve that history.

6. Delaying the reporting process

The NFIU requires suspicious transactions to be reported promptly, with the 24-hour requirement applying to the reporting obligation under the MLPPA. 

Compliance teams therefore need a process that can move quickly from detection to investigation and reporting.

What Is the Difference Between an STR and a CTR in Nigeria?

An STR and a CTR serve different reporting purposes.

An STR is suspicion-based, while a CTR is threshold-based.

The NFIU currently states that CTRs include domestic transactions of ₦5 million and above for individuals and ₦10 million and above for corporate entities, as well as certain transactions involving transfers to or from foreign countries of $10,000 or more. 

A transaction can therefore require a CTR because it meets the applicable threshold without necessarily being suspicious. Conversely, a transaction below that threshold can still require an NFIU STR if there are reasonable grounds for suspicion.

The NFIU also confirms that where a transaction is first reported as a CTR and later identified as suspicious, both reports are required. 

How AI Transaction Monitoring Supports STR Reporting

For banks and fintechs processing large volumes of transactions, manually identifying suspicious patterns can be difficult.

AI-powered transaction monitoring can help compliance teams identify unusual behaviour, detect patterns and prioritise transactions for investigation.

For example, monitoring technology can help identify:

• Unusual transaction frequency

• Sudden changes in customer behaviour

• Structuring patterns

• Transactions that differ significantly from expected activity

• Connections between accounts or entities

• Other rules and risk indicators configured by the institution

But AI should support the investigation process, not replace compliance judgement.

The NFIU's guidance recognises that transaction monitoring systems can generate alerts that ultimately do not qualify as suspicious. Those alerts still need to be reviewed and appropriately documented. 

A practical workflow is therefore:

Transactions → Monitoring → Alert → Investigation → Case → STR

The monitoring system identifies the signal. The compliance team investigates the context, determines whether there are reasonable grounds for suspicion and decides whether to submit the suspicious transaction report.

This approach makes it easier to move from transaction monitoring to an NFIU STR without treating every automated alert as a regulatory filing.

How Youverify Helps Financial Institutions Manage STR Reporting

The challenge with suspicious transaction reporting is often not identifying one suspicious transaction. It is keeping the information required for the report connected throughout the investigation.

A transaction monitoring alert may sit in one system, customer information in another, investigation notes somewhere else and the final report in a separate workflow.

Youverify connects these stages.

With Youverify's Regulatory Reporting, compliance teams can move from an investigated case to a structured regulatory report while keeping relevant information from the compliance workflow connected to the reporting process.

This gives compliance teams a clearer record of what triggered the investigation, what was reviewed, why suspicion was established and what information was used for the final report.

For How to file STR, this connected workflow can reduce the amount of manual information gathering required between investigation and report preparation while keeping the compliance professional in control of the final decision and submission.

The goal is not to have AI decide that a customer is suspicious. It is to give the compliance team the information and workflow needed to investigate the signal, document the reasoning and complete the suspicious transaction report accurately.

You can also learn more about, AML compliance in Nigeria, and SAR best practices for African banks.