Executive Summary
The Bank Secrecy Act's Currency Transaction Report requirement triggers at $10,000 in a single rail/day, and most structuring-detection systems only watch a single rail's transaction stream for the classic "just-under-threshold, repeated" evasion pattern. JIL Sovereign's cross-rail correlation signal instead aggregates a sender's transaction totals across every payment rail they touched (ACH, wire, card, and instant payment) in a rolling window, and specifically flags the case where the combined sum crosses the CTR-equivalent threshold while every individual rail's total stays under it.
Problem Statement
Legacy AML transaction-monitoring systems are typically deployed per channel - the ACH monitoring system watches ACH, the wire desk watches wires, the card network watches card transactions - because those channels historically ran on separate processing cores. A sophisticated structurer exploits exactly this seam: split a $15,000 movement into $6,000 by ACH, $5,000 by wire, and $4,000 by instant payment, and no single-rail monitor ever sees a transaction above its own threshold, because none of them is designed to look across the boundary.
Technical Architecture
Detection Flow
For a given sender/receiver pair, the engine aggregates transaction totals grouped by declared payment rail over a rolling seven-day window. Two conditions are then tested independently:
| Signal | Condition | Score Contribution |
|---|---|---|
| Multi-rail detected | Sender used more than one rail to the same receiver in the window | +30 |
| Cross-rail splitting | Combined total across rails exceeds $10,000 while every individual rail's total stays under $10,000 | +40 |
| Sender rail diversity | Sender used three or more distinct rails in 24 hours (any receiver) | +20 |
The signal triggers at a combined score of 25 or above. It runs alongside a companion four-rail coverage attestation that continuously confirms all four mandated rails - check, ACH, wire, and instant, plus card and crypto - are actively evaluated by the same verdict engine, consistent with the OCC, Federal Reserve, and FDIC's joint expectation of comprehensive rail coverage in transaction-monitoring programs.
Prior Art Differentiation
| Approach | Monitoring Scope | Detects Cross-Rail Splitting? |
|---|---|---|
| Per-channel legacy core monitoring | Single rail (ACH-only, wire-only) | No - blind to activity on other rails |
| Generic velocity-only monitors | Transaction frequency, single rail | No - counts frequency, not cross-rail sum |
| JIL Sovereign | All rails, unified evaluation | Yes - explicit sum-exceeds-but-no-rail-exceeds test |