Check fraud accounts for 30% of all fraud losses in the US, second only to debit card fraud, and shows no sign of slowing.
Hawk, which offers AI tools to help firms combat financial crime, recently delved into the check fraud trends in 2026.
Between 2021 and 2023, suspicious activity reports surged by 90%, with recent cases including a $6m altered plumbing cheque in Memphis, a $20m construction materials scam in New York, and four Florida men attempting to cash a $27m US Treasury cheque.
Fraud detection specialist Hawk has been tracking these shifts closely, warning that institutions relying on outdated systems will continue bearing the heaviest losses.
Mail theft: the easiest entry point
Organised criminals continue to target USPS collection boxes and postal carriers, with the theft of master “arrow keys” granting access to entire neighbourhoods’ mailboxes proving especially problematic. Between February and August 2023 alone, financial institutions reported $688m in suspicious activity tied to mail theft-related check fraud, it said. The US Postal Inspection Service recovers over $1bn in fraudulent cheques annually.
Hawk points to anomaly detection models that flag deviations from normal account behaviour, typology-specific models trained on known fraud patterns, and cross-rail monitoring spanning cheque, ACH, wire, and card channels as among the most effective countermeasures available to banks today.
Dark web marketplaces industrialise stolen cheques
Stolen cheques are no longer used once, they are photographed and sold through dark web platforms and encrypted messaging apps. According to Recorded Future, half of all stolen cheque images appear on dark web platforms within eight days of theft. Researchers tracked 1.9 million stolen US bank cheques posted across more than 700 Telegram channels in 2024 alone.
To combat this, Hawk highlights computer vision models analysing signature geometry and entity graph tools mapping relationships between accounts, devices, and deposit locations as critical capabilities for identifying fraud rings operating across multiple institutions.
Mobile deposits exploited at scale
Mobile Remote Deposit Capture (MRDC) has become a preferred channel for fraudsters, eliminating the in-person scrutiny of a bank teller. In 2024, 65% of financial institutions reported check fraud through remote deposit capture, and 80% faced attempted fraud via mobile deposits, it said.
To addresses this Hawk points to behavioural biometrics, including the tracking of typing rhythm, mouse precision, and device tilt. It also highlights device intelligence tools for monitoring IDs, IP addresses, and geolocation to separate legitimate users from automated fraud operations.
AI-powered forgeries lower the barrier to entry
“Check cooking”, which is a fully digital forgery requiring no physical cheque or chemicals, is now accessible to almost anyone with a computer and printer. Generative AI tools have eliminated most technical barriers, meaning institutions face threats from lone individuals and large criminal operations alike.
With AI image forensics models, which are trained on millions of cheque images, firms can detect subtle digital alterations invisible to human reviewers, flagging font inconsistencies, layout irregularities, and mismatches between written and numeric amounts before transactions complete.
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