Rising Tides Lift All Boats: The Sustained Dominance and Global Impact of the US Dollar as the Reserve Currency

This paper investigates whether the euro or renminbi could join or even replace the US dollar as a dominant global reserve currency. The US dollar has long been dominant in international trade and finance, due to the size and stability of the US economy and the liquidity of US financial markets. The euro of the European Union (EU) and the renminbi of China challenge the hegemony of the US dollar. The Eurozone's institutional framework provides political stability and strong monetary authority, which make the associated currency, the euro, attractive as a potential reserve currency. China’s rise as a global economic power promotes the use of its currency in international transactions, propelling global acceptance of the renminbi. China has explicitly challenged US dominance in many international arenas, including finance. In this paper, it is useful for an econophysics approach to measure the sign of the strength of coupling. This approach is adapted to define the divergence rate of the US dollar in relation to other currencies, specifically the euro and the renminbi, by quantifying how the dollar diverges over time based on currency indexes. It involves calculating forces that represent the divergence rates between the US dollar and these currencies, using a modified version of Coulomb's law. It also illuminates the dynamics of reserve currency competition, reaffirming the US dollar's central role in the global financial system from 2001 to 2022. Despite the emergence of potential challengers like the euro and renminbi, the dollar’s dominance is likely to continue. As China’s economy, international trade, and military power have expanded, the renminbi is increasingly seen as a potential reserve currency in the global financial system. However, China has shown a willingness to centralize political power, perhaps making other countries more likely to resist the renminbi becoming a reserve currency. The euro and renminbi do not present credible alternatives to the US dollar because (1) political fragmentation within the EU and differing fiscal policies among member states undermine the euro's reliability as a universal reserve asset, and (2) China enacts significant capital controls, lacks financial market transparency, and maintains a tight grip on economic policies. The US dollar's unparalleled liquidity, its deep financial markets, and America’s geopolitical influence ensure the dollar’s continued dominance as the world's primary reserve currency. The inherent structural and political challenges the euro and renminbi face make both unlikely to displace the dollar in the foreseeable future. Broader US hegemony, arising from it having the world's largest economy and strongest military, has supported the dollar’s dominant role as a reserve currency, a dominance expected to endure.