How did you come to choose your research topic?
Entirely by chance. During my master’s at the Institute, I couldn’t secure any internship that summer. A classmate who had just received a last-minute offer at the WTO asked me to cover his research assistantship on corporate bonds in emerging markets. That short-term job turned into a full-year research assistant position — and into a new curiosity about how debt works in developing economies.
A year after, I joined Professor Ugo Panizza’s SNIS-funded project, which allowed me to build large datasets on sovereign bonds and explore how countries actually borrow. Having that time and freedom to dig deep into emerging-market data gradually shaped my PhD topic — from a mere empirical exercise into a broader inquiry about how exchange rates, sovereign financing and currency choice in trade connect fiscal and external vulnerabilities in developing economies.
The research project has ended, but this is only the beginning for a research series based on the large database we have built. What began as a coincidence evolved into a long-term research agenda for my career.
Can you describe each of your PhD essays?
The first essay, “Monetary Shocks and Fiscal Consequences”, asks how exchange-rate movements affect government revenues in emerging markets. When a country’s currency depreciates against the dollar, do its fiscal revenue rise or fall?
Using data for about 90 countries and econometric models (OLS, GMM) complemented by a calibrated theoretical model, I find that a depreciation typically raises corporate-income-tax and total-tax revenues for about a year. The reason is twofold depending on the currency choice in trade: exporters’ profits rise in local currency, and/or demand expands temporarily. In other words, exchange-rate shocks have short-term fiscal benefits and heterogeneous macro pressures conditional to their currency choice in trade.
The second essay, “Determinants of Sovereign Bond Issuance in Emerging Markets”, turns to the supply side of public debt. It builds an entirely new dataset of more than 75,000 bond auctions across 20 emerging economies from 2000 to 2023.
Together with my coauthors Mark Manger and Ugo Panizza, we find a clear pattern: governments issue local-currency debt mainly to refinance maturing obligations, following a mechanical fiscal calendar. Foreign-currency borrowing, by contrast, is relatively opportunistic — governments issue more when global financial conditions are favourable and pull back when external rates or risk premiums rise. The study shows that debt managers treat local and foreign markets as two distinct instruments: one to keep the system running, the other to manage exposure and cost expectation.
Finally, the third essay, “The Impact of China on Trade Invoicing”, explores how China’s rise as both a trading partner and a major commodity-exchange hub influences the currency choice in global trade. Using data on 100 countries and commodity deliveries in Chinese exchanges, I find that simply exporting more to China does not change their currency choice pattern in trade. But when China’s organised commodity demand is high, exporters of raw materials are more likely to shift away from dollars. This suggests that China’s market structure — not yet the renminbi itself — is already reshaping pricing norms in global trade.
What is the key takeaway from your research?
Emerging economies often receive less attention, yet they are central to the journey from aid reliance to resilient, self-sustaining growth. My work highlights how exchange-rate dynamics, sovereign financing choices, and evolving trade-pricing norms can strengthen fiscal stability, deepen local capital markets, and lower transaction costs — practical steps that help countries mobilise domestic resources and thrive on their own terms.
What are you doing now?
On the professional side, since February 2025, I have served as an economist (Associate Economic Affairs Officer in UN jargon) at the United Nations Economic Commission for Africa (UNECA) in Addis Ababa, Ethiopia. My work focuses on macro-financial analysis and debt sustainability in African economies — applying the same evidence-based approach from my PhD to continent-wide policy support.
I also contribute to the maintenance of UNECA’s in-house forecasting model, including regular updates to continental and country outlooks and delivery of capacity-building workshops. My first mission was to Botswana’s Ministry of Finance, where I help training a new cohort of staff to operate the ECA forecasting model.
On the research side, the project with Professor Ugo Panizza sparked a broader collaboration with researchers across three continents (from academia and the World Bank) on Africa’s sovereign borrowing. The outcome is the African Debt Database (ADD), a comprehensive resource tracing both domestic and external sovereign debt instruments at a granular level. We have made the data publicly available at africandebtdatabase.com, with the launch on 13 October 2025 at DebtCon in Washington, DC. It appears I will remain engaged in the sovereign-debt space for some time.
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On 25 September 2025, Ka Lok Wong defended with summa cum laude his PhD thesis in International Economics, titled “Essays in International Finance and Macroeconomics”. Professor Ugo Panizza (second to the right) presided over the committee, which included Professor Cédric Tille (left), Thesis Supervisor, and Professor Jean-Paul Renne (right), Faculty of Business and Economics, University of Lausanne.
Citation of the PhD thesis:
Wong, Ka Lok. “Essays in International Finance and Macroeconomics.” PhD thesis, Graduate Institute of International and Development Studies, Geneva, 2025.
Access:
Members of the Geneva Graduate Institute can access the thesis via this page of the repository. Others can contact Dr Wong.
Banner image by Aleksandar Milosevic/Shutterstock.
Interview by Nathalie Tanner, Research Office.
Views are Dr Wong’s own, not reflecting those of his affiliation.