India, May 22 -- In the summer of 2022, Bangladeshis began getting used to the dark. Load-shedding - scheduled power cuts that had largely faded from daily life during a decade of economic expansion - came back with a force that caught many off guard. Factories throttled output.

Households sweltered through hours without fans or air conditioning. Hospital administrators worried about backup power. The economic miracle that Bangladesh had spent twenty years building was flickering, quite literally, under the strain of a foreign exchange crisis that few had seen coming at such speed.

The story of how Bangladesh's reserves collapsed is now fairly well understood. Forex holdings that had touched nearly $46 billion in August 2021 fell sharpl...