The U.S. Department of the Treasury’s Financial Crimes Enforcement Network (FinCEN) published a Financial Trend Analysis on patterns and trends in Bank Secrecy Act (BSA) data linked to fentanyl-related illicit finance. FinCEN reports that between January and December 2024, financial institutions filed 1,246 BSA reports identifying suspected fentanyl-related activity totaling approximately USD 1.4 billion in suspicious transactions, spanning precursor chemical procurement, trafficking, and fentanyl-linked money laundering. The analysis identifies Mexico and the People’s Republic of China as the top two foreign countries listed in subject address fields in fentanyl-related BSA reports filed in 2024 and links the supply chain to Mexican cartels sourcing precursor chemicals and manufacturing equipment primarily from PRC-based suppliers. Additional findings include the use of front companies, money mules, and U.S.-based intermediaries to procure precursor chemicals; PRC suppliers accepting a wide range of payment methods and marketing via public advertisements including e-commerce; concentrations of U.S. subject activity in populous states and southwest border counties in California and Arizona; and domestic sales referenced as cash and peer-to-peer transfers in 54% and 51% of reports, respectively. Reported laundering methods ranged from simple to complex, including suspected Chinese money laundering organizations potentially moving proceeds on behalf of cartels. FinCEN encourages financial institutions to review its August 2019 and June 2024 advisories on trafficking of fentanyl, fentanyl analogues, other synthetic opioids, and associated precursor chemicals and manufacturing equipment.