Abstract : Global payment platforms have grown into extraordinarily complex financial ecosystems, ones that touch dozens of legal entities, hundreds of currency pairs, and numerous regulatory perimeters, often within the lifecycle of a single transaction. This technical review examines how multi-entity ledger architectures can be designed to meet that complexity, with particular focus on customer liability management, payables and receivables tracking, revenue recognition, transaction cost monitoring, loss accounting, and cash management reconciliation. Beyond structural design, the review explores how embedded control frameworks, self-healing exception pipelines, and trend-based anomaly detection can meaningfully reduce operational overhead while improving financial accuracy. Practical diagnostic examples are included, including how a rising transaction cost ratio can signal that an external processor has silently risk-flagged a merchant's traffic due to missing critical data fields. Visual dashboards and architecture diagrams support these concepts throughout. The article uses peer-reviewed and practitioner literature from the fields of fintech, distributed systems, and financial governance