整合碎片化网络：货币和支付互操作性的价值

Integrating FragmentedNetworks: The Value ofInteroperability in Moneyand Payments Alexander Copestake, Divya Kirti, Maria Soledad Martinez Periaand Yao Zeng WP/25/126 IMF Working Papersdescribe research inprogress by the author(s) and are published toelicit comments and to encourage debate.The views expressed in IMF Working Papers arethose of the author(s) and do not necessarilyrepresent the views of the IMF, its Executive Board,or IMF management. IMF Working PaperResearch Department Integrating Fragmented Networks: The Value of Interoperability in Money and Payments Prepared byAlexander Copestake, Divya Kirti, Maria Soledad Martinez Peria and Yao Zeng* 1 Authorized for distribution byGiovanni Dell’Ariccia June2025 IMF Working Papersdescribe research in progress by the author(s) and are published to elicitcomments and to encourage debate.The views expressed in IMF Working Papers are those of theauthor(s) and do not necessarily represent the views of the IMF, its Executive Board, or IMF management. ABSTRACT:Payments technologies pose an economic dilemma: networkeffects canlead to a small number of dominant platforms,but efforts toincreasechoice can risk market fragmentation.We examine whetherinteroperabilitycan helpresolve this tension, using data from India’s UnifiedPayments Interface—the world’s largest fast payment system by volume—aswell asfroma major pre-existing fintech firm.When thetwo networks becameinteroperable,overallusage of digital payments rose. Consistent with a modelof payment choice that we propose, this increase wasdriven byregions wheredigital payments were more fragmented across platforms ex ante.Our modelimpliesthat the unification of networks increased total usage of digitalpayments by more than50% in the year after integration. *1We are grateful to Ritesh Shukla, Nikita Agrawal, Kapil Patil, and Harshya Matthews at NPCI for sharing data and for many helpfulconversations. We thankTobias Adrian,Itai Agur, Tanuj Bhojwani, Daniel Björkegren, Luis Breuer, Markus Brunnermeier, KamyaChandra, Nada Choueiri,Giovanni Dell'Ariccia,Harald Finger, Lukas Freund,Pierre-Olivier Gourinchas,Deepro Guha, SrinivasGynedi, Vikram Haksar, Paavi Kulshreshth, Nikhil Kumar, Rohit Kumar, Nicola Limodio,Filippo Mezzanotti,Sudip Mohapatra,DivyanshuPathak,Manasa Patnam,Nicola Pierri,Andrea Presbitero,Dinar Prihardini,Guillermo Galicia Rabadan,KarthikRaghupathy, Pallavi Rao, Saravana Ravindran,Edona Reshidi,Marco Reuter,Krishna Srinivasan, Nujin Suphaphiphat, Jay Surti,Ashutosh Thakur, and K Vijayakumar for helpful discussions, as well as seminar participants at the IMF and the Lee Kuan Yew Schoolof Public Policy. Cage Englander and Ariadne Checo de los Santos providedexcellent research assistance. 1Introduction Money is a fundamental economic technology characterized by network effects (Menger, 1892;Fisher, 1911; Krugman, 1984): its value rises with others’ willingness to accept it. Modern digitalpayment technologies share this characteristic and could generate even stronger network benefits(Crouzet, Gupta, and Mezzanotti, 2023; Alvarez, Argente, Lippi, Méndez, and Patten, 2023), cre-ating a dilemma for the optimal design of payment systems. On one hand, network effects canconcentrate users on a few dominant platforms, limiting user choice and potentially raising con-cerns of rent extraction (Katz and Shapiro, 1985; Brunnermeier and Payne, 2022, 2023). On theother hand, introducing new platforms can fragment markets (Vayanos, 1999; Duffie, 2023), re-ducing the inherent network benefits of converging on leading platforms.This dilemma recursin many contexts, from regulating card networks and fintech firms to introducing public paymentoptions like FedNow or a Digital Euro (Brainard, 2019; Lagarde, 2025; Lane, 2025). Is there away to avoid fragmentation without sacrificing user choice? In this paper, we study payment interoperability, which offers a potential escape from thedilemma yet has not been widely studied academically. By enabling users to transact seamlesslyacross payment platforms, interoperability can unlock the benefits of network unification withoutrequiring centralization on a single private platform provider—preserving choice for users. It couldtherefore allow users to reap the best of both worlds: the freedom to choose their favorite platform,alongside access to the full network of users. Despite its importance and anecdotal support, dataconstraints have made it difficult to study the role of interoperability in encouraging usage of digitalpayments. We present a theoretical framework and tightly connected empirical evidence showing thatinteroperability can increase adoption and usage of digital payments by integrating fragmentednetworks.To do so, we leverage novel data coveringboththe universe of payments on India’sUnified Payments Interface (UPI)—the world’s largest fast payment system by volume—and allpayments on a major pre-existing fintech platform.1Our data allow us to observe—at a