This article examines the pivotal role of the Bank of Indochina (BIC) in transforming payment behaviors in Vietnam between 1875 and 1930. Drawing on archival sources and the Diffusion of Innovations theory, the study analyzes the shift from traditional commodity money (zinc, copper, and silver coins) to fiat banknotes. The findings reveal that the BIC successfully modernized user behavior through three core strategies: establishing issuance monopolies, guaranteeing exchange liquidity, and leveraging institutional pressure from the colonial administration. The research highlights that the establishment of institutional trust was the decisive factor in breaking the indigenous population's psychological preference for metallic currency. This paper contributes a novel perspective to Vietnamese economic history through the lens of behavioral economics.

Dr.Duong To Quoc Thai, Dr.Duong Thi Ngoc Minh, Nguyen Trung Hieu, "The Transition from Commodity Money to Fiat Money: The Role of the Bank of Indochina in Modernizing Payment Behaviors in Vietnam (1875–1930)" International Journal of Advanced Multidisciplinary Research and Educational Development, V2(1): Page(781-785) Jan-Feb 2026. ISSN: 3107-6513. www.ijamred.com. Published by Scientific and Academic Research Publishing.