The US Department of the Treasury’s Financial Crimes Enforcement Network (FinCEN) issued a Financial Trend Analysis summarizing patterns and trends in Bank Secrecy Act (BSA) reports linked to fentanyl-related illicit finance. It found that, between January and December 2024, financial institutions filed 1,246 BSA reports referencing suspected fentanyl-related activity involving approximately USD 1.4bn in suspicious transactions, spanning precursor chemical procurement, fentanyl trafficking and fentanyl-linked money laundering. FinCEN’s analysis cites Mexican cartels as primary actors in synthesizing, trafficking and smuggling illicit fentanyl into the United States, with precursor chemicals and manufacturing equipment primarily sourced from the People’s Republic of China (PRC). Mexico and the PRC were the top two foreign countries appearing in subject address fields of fentanyl-related BSA reports filed in 2024. Additional observed typologies include the use of front companies, money mules and US-based intermediaries to procure precursor chemicals from PRC-based suppliers; PRC suppliers accepting varied payment methods and using public advertising, including e-commerce platforms; concentrations of US-linked activity in populous states and southwest border counties in California and Arizona; domestic sales primarily involving cash and peer-to-peer transfers (referenced in 54% and 51% of reports, respectively); and laundering methods ranging from basic to complex, including suspected Chinese money laundering organizations facilitating movement of proceeds on behalf of cartels. FinCEN encouraged financial institutions to review its August 2019 and June 2024 advisories on fentanyl, fentanyl analogues, other synthetic opioids, and related precursor chemicals and manufacturing equipment.