The Exchange Rate Effects of a Singaporean Closed-Border Retail Central Bank Digital Currency: A Counterfactual Analysis
Abstract
Central bank digital currencies (CBDCs) are heralded as the next innovation in currency usage. Their unique architecture provides both liquidity and remuneration to investors. This paper aims to assess the exchange rate changes caused by differing plausible implementations of CBDCs due to changes in portfolio allocations of investors. Furthermore, the paper also aims to identify the ideal form of CBDC implementation.
This study uses a novel aggregated uncovered interest parity equation to connect interest rate differentials between Singaporean and international assets to estimate exchange rate differentials. Three counterfactual CBDC regimes are modelled over the period between 2000 Q1 and 2024 Q4, namely the Baseline Rule (no interest rate on CBDCs), the Markdown Rule (a discounted rate on CBDCs), and the Taylor Rule (interest rate set as per inflation and output gaps). These regimes are compared with the non-CBDC counterfactual which is modelled using the standard uncovered interest parity equation.
The criteria for comparison are path fidelity and volatility of the exchange rate. It was found that the Markdown Rule is the ideal form of CBDC implementation. Furthermore, it was also found that the Singapore dollar appreciates 35.8% to 80.4% across CBDC regimes. These findings are of great importance to the Monetary Authority of Singapore, as they can significantly affect its unique exchange-rate-targeting monetary policy.
References
Agur, I., Ari, A., & Dell’Ariccia, G. (2019). Designing central bank digital currencies. ADBI Working Paper Series No. 1065. Asian Development Bank Institute. https://www.adb.org/sites/default/files/publication/546921/adbi-wp1065.pdf
Andolfatto, D. (2021). Assessing the impact of central bank digital currency on private banks. The Economic Journal, 131(634), 525–540. https://doi.org/10.1093/ej/ueaa073
Auer, R., Cornelli, G., & Frost, J. (2020). Rise of central bank digital currencies: Drivers, approaches and technologies. Bank for International Settlements Working Paper No. 880. https://www.bis.org/publ/work880.htm
Barrdear, J., & Kumhof, M. (2016). The macroeconomics of central bank issued digital currencies. Bank of England Staff Working Paper No. 605. https://doi.org/10.2139/ssrn.2811208
Bass, F. M. (1969). A new product growth model for consumer durables. Management Science, 15(5), 215–227. https://doi.org/10.1287/mnsc.15.5.215
Benigno, P., Schilling, L. M., & Uhlig, H. (2022). Cryptocurrencies, currency competition, and the impossible trinity. Journal of International Economics, 136, 103601. https://doi.org/10.1016/j.jinteco.2022.103601
Bindseil, U. (2022). Central bank digital currencies in a world with negative nominal interest rates. In M. Heckel & F. Waldenberger (Eds.), The future of financial systems in the digital age (pp. 75–88). Springer. https://doi.org/10.1007/978-981-16-7830-1_5
Brunnermeier, M. K., & Niepelt, D. (2019). On the equivalence of private and public money. Journal of Monetary Economics, 106, 27–41. https://doi.org/10.1016/j.jmoneco.2019.07.004
Chiu, J., & Davoodalhosseini, S. M. (2023). Central bank digital currency and banking: Macroeconomic benefits of a cash-like design. Management Science, 69(11), 6708–6730. https://doi.org/10.1287/mnsc.2021.02763
Chow, H. K., Lim, G. C., & McNelis, P. D. (2014). Monetary regime choice in Singapore: Would a Taylor rule outperform exchange-rate management? Singapore Management University Working Paper. https://ink.library.smu.edu.sg/cgi/viewcontent.cgi?article=2523&context=soe_research
Das, M., Mancini-Griffoli, T., Nakamura, F., Otten, J., Soderberg, G., Sole, J., & Tan, B. J. (2023). Implications of central bank digital currencies for monetary policy transmission. IMF FinTech Note 2023/010. International Monetary Fund. https://www.imf.org/en/Publications/fintech-notes/Issues/2023/09/15/Implications-of-Central-Bank-Digital-Currencies-for-Monetary-Policy-Transmission-538517
Drechsler, I., Savov, A., & Schnabl, P. (2021). Banking on deposits: Maturity transformation without interest rate risk. The Journal of Finance, 76(3), 1091–1143. https://doi.org/10.1111/jofi.13013
European Central Bank. (2021). “Hic sunt leones” – Open research questions on the international dimension of central bank digital currencies. https://www.ecb.europa.eu/press/key/date/2021/html/ecb.sp211019_1~b91b5f9595.en.html
Faia, E., Salomao, J., & Ventula Veghazy, A. (2022). Granular investors and international bond prices: Scarcity-induced safety. Working paper. https://sbfin.org.br/files/granular_investors_latest.pdf
Fan, R., Walker, T. B., & Wright, A. (2025). Central bank digital currency in small open economies. Latin American Journal of Central Banking, 6(2), 100151. https://doi.org/10.1016/j.latcb.2024.100151
Fernández-Villaverde, J., Sanches, D., Schilling, L., & Uhlig, H. (2020). Central bank digital currency: Central banking for all? NBER Working Paper No. 26753. https://www.nber.org/papers/w26753
Ferrari, M., Minesso, M., Mehl, A., & Stracca, L. (2020). Central bank digital currency in an open economy. ECB Working Paper Series No. 2488. https://www.ecb.europa.eu/pub/pdf/scpwps/ecb.wp2488~fede33ca65.en.pdf
George, A., Xie, T., & Alba, J. D. (2020). Central bank digital currency with adjustable interest rate in small open economies. ACI Policy Research Paper #05-2020. https://lkyspp.nus.edu.sg/docs/default-source/aci/aciprp202005.pdf
Hamilton, J. D. (1994). Time series analysis. Princeton University Press.
Hemingway, B. (2023). The impact of central bank digital currency on bank deposits and the interbank market. ECB Conference Paper. https://www.ecb.europa.eu/press/conferences/shared/pdf/20231123_cepr_ecb/Hemingway_paper.en.pdf
Hodrick, R. J., & Prescott, E. C. (1997). Postwar U.S. business cycles: An empirical investigation. Journal of Money, Credit and Banking, 29(1), 1–16. https://doi.org/10.2307/2953682
Kumhof, M., & Noone, C. (2021). Central bank digital currencies: Design principles for financial stability. Economic Analysis and Policy, 71, 553–572. https://doi.org/10.1016/j.eap.2021.06.012
Monetary Authority of Singapore. (2023). Project Orchid. https://www.mas.gov.sg/schemes-and-initiatives/project-orchid
Niepelt, D. (2020). Reserves for all? Central bank digital currency, deposits, and their (non)-equivalence. International Journal of Central Banking, 16(3), 211–238. https://www.ijcb.org/journal/ijcb20q2a6.htm
OECD. (2023). ICIO-TiVA highlights: GVC indicators for Singapore. https://www.oecd.org/content/dam/oecd/en/topics/policy-sub-issues/trade-in-value-added/tiva-2023-SGP.pdf
Popescu, A. (2022). Cross-border central bank digital currencies, bank runs and capital flows volatility. IMF Working Paper 22/83. International Monetary Fund. https://www.imf.org/en/Publications/WP/Issues/2022/05/06/Cross-Border-Central-Bank-Digital-Currencies-Bank-Runs-and-Capital-Flows-Volatility-517625
Reserve Bank of Australia. (2015). Wholesale CBDC. https://www.rba.gov.au/payments-and-infrastructure/central-bank-digital-currency/wholesale-central-bank-digital-currency.html
Sultan, F. E., Farley, J. U., & Lehmann, D. R. (1990). A meta-analysis of applications of diffusion models. Journal of Marketing Research, 27(1), 70–77. https://doi.org/10.2307/3172552
Tan, B. J. (2024). Central bank digital currency and financial inclusion. Journal of Macroeconomics, 81, 103620. https://doi.org/10.1016/j.jmacro.2024.103620
Vollmar, S., & Wening, F. (2024). The impact of CBDC on a deposit-dependent banking system. Journal of Financial Stability, 73, 101283. https://doi.org/10.1016/j.jfs.2024.101283
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