How Financial Data Helps Solve IRS Criminal Cases

When it comes to financial crimes investigated by IRS Criminal Investigation (IRS-CI), the agency’s most effective tool is likely not what you think. It’s data—specifically, Bank Secrecy Act (BSA) data.

About the BSA

The Bank Secrecy Act was enacted in 1970 amid growing concern that organized crime, tax evaders, and others were moving large sums of money through banks—often offshore—without leaving a usable investigative trail. The statute required financial institutions to keep certain records and report large cash transactions, establishing the $10,000 reporting threshold for currency transactions that remains in place today.

The BSA expanded significantly in the 1980s through anti-money-laundering reforms (largely in response to the war on drugs) and again after 9/11 with the USA PATRIOT Act. Today, the BSA is administered by the Financial Crimes Enforcement Network (FinCEN)—a name you may recognize if you file an FBAR. The BSA requires financial institutions to file reports, implement compliance programs, and conduct customer due diligence, creating a nationwide financial intelligence system that makes illicit money visible and traceable.

CI and BSA Data

“BSA data is often the first signal that something isn’t right,” explains CI Chief Guy Ficco. “These filings become essential puzzle pieces in identifying patterns, following financial trails and building cases that protect taxpayers.”

In fiscal year (FY) 2025, 94% of CI cases were searched against BSA data, resulting in more than 3.9 million searches of BSA filings. Those filings are used to build criminal cases against fraudsters engaged in money laundering, cybercrimes, abuse of government programs, narcotics trafficking, and other crimes.

This reflects how modern financial crime investigations are conducted. Financial crime is rarely uncovered through dramatic informants or surprise discoveries, but through pattern recognition. Suspicious Activity Reports (SARs), Currency Transaction Reports (CTRs), and Forms 8300 provide the structured data that allows investigators to identify and connect those patterns.

Kinds of Reports

What kind of information does CI obtain from those reports? FinCEN’s Year-in-Review shows that roughly 432,000 registered filers participated in BSA reporting in FY 2024. The actual number of filings runs into the tens of millions across SARs and CTRs.

Suspicious Activity Reports (SARs) are filed by banks, credit unions, broker-dealers, money services businesses, casinos, and other financial institutions subject to the BSA when they detect transactions that may involve violations of law or attempts to evade reporting requirements. A SAR must generally be filed within 30 calendar days of the initial detection of facts that may constitute suspicious activity, or within 60 days if no suspect is identified. The report includes identifying information about the subject, account details, transaction details, dollar amounts, dates, and a narrative description of the suspicious conduct. FinCEN received approximately 4.7 million SARs in FY 2024, an average of roughly 12,870 filings per day.

Currency Transaction Reports (CTRs) are filed by financial institutions when a person conducts a single cash transaction exceeding $10,000 in a business day, or multiple cash transactions that aggregate to more than $10,000 in a business day. The report must be filed within 15 calendar days of the transaction. It includes the individual’s identifying information, the amount and type of transaction (such as deposit, withdrawal, or exchange), account numbers, the transaction date, and information about the financial institution. In FY 2024, financial institutions filed about 20.5 million CTRs, an average of approximately 56,160 filings per day.

Any person engaged in a trade or business who receives more than $10,000 in cash in a single transaction or in two or more related transactions in the course of that trade or business must file Form 8300. The form must be filed within 15 days of receiving the cash. It reports the payer’s name, address, taxpayer identification number, the amount and date of cash received, the nature of the transaction, and information about the business filing the form. The business must also provide a written statement to the payer by January 31 of the following year informing them that the information was reported. In FY 2024, businesses filed approximately 470,400 Forms 8300 reporting cash payments over $10,000.

All of these reports are filed electronically with FinCEN and stored in FinCEN’s BSA database.

Is $10,000 Too Low?

The $10,000 threshold remains a subject of debate. If adjusted for inflation from 1970, the threshold would exceed $85,000 today.

Law enforcement, however, generally maintains that the threshold remains operationally effective. Take CTRs, for example. Most investigative CTR amounts cluster between $12,000 and $12,543, and nearly half of relevant investigations involve amounts under $20,000, which law enforcement suggests indicate that the threshold is effective. This is especially true when you look at reports that suggest structuring.

Structuring occurs when transactions are broken into smaller amounts to avoid reporting requirements triggered at $10,000. It is frequently charged in money laundering cases. For example, rather than depositing $100,000 at once, an individual might make a series of smaller deposits across different days or accounts. Individuals who carry out those deposits are sometimes referred to as “runners” or “smurfs” (which is why you may also see it referred to as smurfing). Structuring itself is illegal when transactions are conducted for the purpose of evading reporting requirements—it’s not illegal merely to deposit less than $10,000.

“Criminals deliberately structure transactions tied to illicit activity to avoid detection,” said Ficco. “CTRs provide concrete transactional data that often serves as evidence when proving criminal activity took place.”

How Does the Data Help Law Enforcement, Including CI?

From FY23 to FY25, CI investigated 1,394 refund fraud cases, with alleged fraud totaling $2.9 billion. Most of those cases (93%) had a BSA filing associated with the primary subject. In those cases, financial movements—rapid deposits of government funds, funnel accounts, and high-velocity withdrawals—often triggered SAR and CTR activity. The resulting reporting helped law enforcement put those behaviors together and see bigger patterns.

During the same period, CI opened 1,006 employment tax evasion cases, with alleged fraud totaling $1.4 billion. Nearly two-thirds (63%) of those investigations had a BSA filing associated with the primary subject.

BSA data also supports prosecutions that result in high conviction rates, multi-year prison sentences, and restitution for victims. From FY23 through FY25, CI cases using BSA filings had a 98% conviction rate. The average prison sentence was 42 months, asset forfeitures exceeded $450 million, and restitution for crime victims totaled nearly $500 million. When law enforcement needs evidence to prosecute these crimes, BSA-related data proves very helpful.

Working Together

CI is not the only federal agency that uses BSA data. The Federal Bureau of Investigation (FBI) and Homeland Security Investigations (HSI) also rely on SARs and CTRs to develop leads and support cases. The FBI reported that in FY 2024, 32% of its active complex financial crime investigations were linked to SARs and CTRs.

And CI doesn’t act alone. It leads or participates in SAR review teams across 94 federal judicial districts. These teams, composed of multiple law enforcement partners, regularly analyze BSA filings to identify actionable SARs, CTRs, and Forms 8300 and assign leads to the appropriate agencies. Between FY23 and FY25, these teams seized assets valued at $385.4 million.

In March 2025, CI announced CI-FIRST (Feedback in Response to Strategic Threats), a public-private partnership to modernize CI’s work with financial institutions. The program provides strategic, non-case-specific feedback on how BSA filings—particularly SARs—are used in tax and financial crime investigations. It includes structured forums and FinTAX crime alerts and advisories that highlight emerging tax-related fraud schemes and reporting indicators. The goal is to improve reporting quality and align financial institution monitoring with CI’s investigative priorities.

Similarly, the Optimizing Financial Records Requests (OFRR) initiative aims to streamline how CI issues legal process—such as summonses, subpoenas, and other financial records requests—and how financial institutions respond. The initiative seeks to standardize request formats, clarify scope and production expectations, and reduce delays in obtaining financial records. By improving consistency and communication between CI and financial institutions, OFRR is intended to shorten investigative timelines and make it more efficient to collect financial evidence.

IRS-CI

CI, the sixth-largest federal law enforcement agency, is the IRS’s criminal investigative arm, responsible for investigating financial crimes such as tax fraud, narcotics trafficking, money laundering, public corruption, healthcare fraud, and identity theft. While other federal agencies have investigative jurisdiction over money laundering and certain BSA violations, the IRS is the only federal agency with investigative jurisdiction over criminal violations of the Internal Revenue Code.

The agency has 18 field offices located across the United States and maintains an international presence through attaché posts abroad.