This archival case study examines the organizational evolution of the Chinese fintech conglomerate Ant Group as an example of the emergence of organizational novelty. To investigate how an e-retailer evolves into a massive financial conglomerate under a shifting regulatory environment, I developed an integrated network-institutional theoretical framework to characterize how the intertwined networks of e-commerce, banking, and governments and institutions co-evolved to shape the genesis and evolution of Ant Group. The archival evidence presents how organizational practices and values (big data and platform mindsets) in E-commerce were transposed to the banking industry at the intersection of three originally separate networks, which completely transformed the way the financial market is organized and the way finance is regulated. Moreover, the network-institutional approach vividly captures how shifting institutions interact with the relational process of transposition and influence intertwined networks’ effects on the generation of novel practices. Under the originally loose regulatory institutions, the Ant group could mobilize a few business and political networks to make the transposition happen. As the regulatory institutions grew more stringent, Ant Group’s extensive business and political networks and central network positions failed to buffer the regulatory uncertainties, resulting in organizational restructuring requested by the Central authorities.