Abstract: A computer-implemented campaign finance compliance system establishes authenticated connections to financial institution data interfaces and maintains a deduplicated transaction record through dual-path synchronization combining event-driven webhook notifications and scheduled cursor-based incremental retrieval with upsert-on-conflict deduplication. A classification engine evaluates normalized transaction records against configurable rule sets, including automated intermediary platform identification. A retroactive cross-report itemization module computes calendar-year-scoped contributor aggregates across multiple reports and retroactively updates itemization status on prior report entries when threshold crossings are detected. A split-transaction module decomposes aggregate bank deposits into constituent entries using a self-referential data model with automatic parent exclusion during report generation.