For much of the last half-century, the study of global exchange rates has been treated as a branch of physics. In the hallowed halls of neoclassical economics, there is a belief in a “natural” state of things, an equilibrium where trade balances and productivity levels act as gravity, pulling currencies back toward their fundamental value. If a country runs a persistent trade surplus, its currency should rise; if its factories become more efficient than its neighbors, its purchasing power should follow.

Yet as we look at the world in January 2026, this elegant clockwork mechanism appears to have broken down. The U.S. dollar, despite decades of eye-watering trade deficits, spent much of the past year defying gravity before its recent 10 percent slide. Meanwhile, the Chinese renminbi has spent nearly four years in a state of “internal depreciation,” with its real effective exchange rate falling by roughly 16-20 percent since 2022. This occurred even as Chinese electric vehicles and high-end electronics flooded global markets, a clear sign of the productivity gains that, in a neoclassical world, should have sent the currency soaring.

The disconnect suggests that we are looking through the wrong lens. Although the real economy of ships and factories still matters, it is increasingly a secondary player to the ghost in the machine: the global financial system. To understand why the world’s most important currencies are moving as they do, one must look past the trade ledgers and into the volatile world........

© Eurasia Review