Which 1997 crisis began with Thailand's decision to let the baht float?

The 1997 crisis that began with Thailand's decision to let the baht float was the Asian financial crisis.

Thailand abandoned its fixed exchange-rate policy on 2 July 1997 after intense pressure on its foreign-exchange reserves. The baht then depreciated sharply, and financial stress spread across several economies in East and Southeast Asia. Countries affected included Indonesia, South Korea, Malaysia, and the Philippines, while Hong Kong’s stock market also came under severe pressure.

The crisis reflected more than currency speculation. Many banks and companies had borrowed heavily in foreign currencies, often with short maturities, while property and equity prices had risen rapidly. When currencies weakened, the local-currency cost of dollar debt increased, causing defaults and further capital flight.

The International Monetary Fund arranged major assistance programs, especially for Thailand, Indonesia, and South Korea. The crisis led governments and institutions across Asia to reconsider exchange-rate regimes, foreign-currency borrowing, banking supervision, and the size of foreign-exchange reserves.