The Bond Index: Quantifying Representational Consistency in Payment Processing Systems -- A Gauge-Theoretic Framework for Invariance Verification in Electronic Funds Transfer

We present the Bond Index ( ), a gauge-theoretic metric for quantifying the representational consistency of payment processing systems. Drawing on the Stratified Geometric Ethics (SGE) framework~, we formalize the observation that a payment system's decisions should be under admissible changes of representation---the same payment encoded as SWIFT MT103, ISO~20022 pacs.008, or any other format must produce identical processing outcomes. We define a space of that preserve economic substance while changing representation, and show that the coherence defect decomposes uniquely into a gauge-removable component (implementation bugs) and an intrinsic anomaly (specification gaps). Applied to the ongoing SWIFT MT-to-MX migration affecting \10T+ in daily cross-border payments, the Bond Index provides a single dimensionless number---calibrated against human domain experts---that determines deployment readiness across five tiers. We describe BondGuard, an open-source reference implementation with 335 tests at 95\ representational inconsistencies are both measurable and remediable. Our framework connects the abstract gauge symmetries of the moral manifold to concrete financial engineering, establishing payment consistency verification as the first commercially deployed application of geometric ethics. Author preprint deposited for archival and citation. Draft — pending author review.