T This study examines the optimizing cash waqf development through islamic bankinginstruments: an institutional synergy approach in consumer financing products at banksyariah indonesia tbk. this research employs a qualitative approach, utilizing documentanalysis, in-depth interviews, and observation. the main focus in this study includeinstitutional synergy as an aspect influencing the optimization of cash waqf. thisrelationship is mediated by the role of regulators (ojk and bwi) and moderated byconsumer financing products and customer participation through a payroll-based waqfscheme.the findings reveal that institutional synergy among islamic banks, waqf managers(nazhir), the indonesian waqf board (bwi), regulators, and the government serves as akey factor in integrating cash waqf into consumer financing products such as griya andmitraguna. the consumer financing-based cash waqf management model enables theallocation of a portion of customers’ installment payments as productive waqf funds, whichcan be invested in sectors such as education, healthcare, and economic empowerment.this research offers a novel contribution by proposing a model for integrating cash waqfinto consumer financing products through a structured and systemic institutional synergyapproach. furthermore, this study recommends strategies to strengthen the cash waqfecosystem through product innovation, digitalization, and regulatory frameworks thatsupport transparency and accountability.the findings are expected to contribute academically to the development of maqashidsharia theory, particularly in relation to jalb al-mashlahah (the attainment of publicwelfare), as well as provide practical contributions to policymaking for the development ofcash waqf in indonesia.