Fiscal Sovereignty and the Shadow Balance Sheet: Professionalized Accountability and Active Substitution in Elite Thai Public Schools

Conventional public budgeting models categorize non-state funding as supplementary to state provision. This study challenges that assumption by documenting a parallel, professionally audited financial ecosystem—a "Shadow Balance Sheet"—within elite Thai public secondary schools. Utilizing Resource Dependence Theory (RDT) and an explanatory mixed-methods design ( schools; 66 interviews), this research identifies a profound Budgetary Delta (+2.06 aggregate gap). Findings indicate a shift from supplementation to Active Substitution, wherein stakeholder networks replace the state as the primary financier of institutional innovation. We provide forensic evidence of a 100-million-baht technological flagship where the network achieved operational completion in under 18 months, bypassing a 36-month bureaucratic cycle. This article contributes to RDT by theorizing "Principal Substitution," and advances hybrid finance literature by deconstructing the "Glass-Box Strategy"—a model of professionalized accountability that secures an Agility Premium for public institutions in fragile state contexts.