Mars or Mercury: The Geopolitics of International Currency Choice

Working Paper: NBER ID: w24145

Authors: Barry Eichengreen; Arnaud J. Mehl; Livia Chitu

Abstract: We assess the role of economic and security considerations in the currency composition of international reserves. We contrast the “Mercury hypothesis” that currency choice is governed by pecuniary factors familiar to the literature, such as economic size and credibility of major reserve currency issuers, against the “Mars hypothesis” that this depends on geopolitical factors. Using data on foreign reserves of 19 countries before World War I, for which the currency composition of reserves is known and security alliances proliferated, our results lend support to both hypotheses. We find that military alliances boost the share of a currency in the partner’s foreign reserve holdings by 30 percentage points. These findings speak to current discussions about the implications of possible U.S. disengagement from global geopolitical affairs. In a hypothetical scenario where the U.S. withdraws from the world, our estimates suggest that long-term U.S. interest rates could rise by as much as 80 basis points, assuming that the composition of global reserves changes but their level does not.

Keywords: International Currency Choice; Geopolitics; Foreign Reserves; Military Alliances

JEL Codes: F0; F33; F51; N0; N1


Causal Claims Network Graph

Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.


Causal Claims

CauseEffect
Share of a currency in foreign reserve holdings (F31)US long-term interest rates (E43)
Currency holdings (F31)Geopolitical alliances (D74)
Military alliances (D74)Share of a currency in foreign reserve holdings (F31)

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