An IMF working paper by economist Brandon Joel Tan models how stablecoins affect parallel foreign‑exchange markets when official dollar access is limited. The study finds that stablecoins can provide dollar‑like claims in economies with fixed or heavily managed exchange rates where banks cannot meet demand, but they may also trigger rapid withdrawals of the domestic currency during periods of stress, potentially intensifying currency runs. Tan notes that the visible, high‑frequency price of stablecoins can signal dollar scarcity and prompt simultaneous abandonments of the local currency when the official rate deviates from market rates. The paper cites examples where retailers at a Bolivian airport accepted USDT as a reference while still taking U.S. dollars or bolivianos, and where Argentine users exchanged pesos for dollar‑pegged tokens in informal channels to preserve savings amid peso depreciation and capital controls. The Financial Stability Board has warned that dollar‑denominated stablecoins could expose emerging economies to currency substitution, weaken monetary policy effectiveness, and circumvent capital‑flow restrictions, urging regulators to assess liquidity and operational risks as the sector expands. The findings suggest that regulators may consider temporary limits on large or panic‑driven transactions during periods of currency pressure.