The Cost of Trust at Scale: Welfare in Payment Infrastructure

Replication data and code for "The Cost of Trust at Scale: Welfare in Payment Infrastructure" by Craig S. Wright (University of Exeter). The paper develops a two-sided payment platform model showing that Budish's (2025, QJE) trust-cost-scales-with-value result is mechanism-specific. When processing and trust are architecturally separated, switching cost is value-independent and welfare gains are quantifiable. The calibration script (calibrate_welfare.py) reproduces Tables 1 and 2 from the paper using publicly available incumbent cost data (Visa Q4 FY2024 Earnings Release, Federal Reserve Payments Study, NACHA) and independently verified engineering data (Halborn Inc. 2026). All input parameters are documented in parameters.json with full source traceability. The conservative welfare floor ($700 million/year) requires only the verified switching-cost differential and US transaction volume; competitive-entry scenarios are sensitivity analysis.