The Thai baht began the 1997 Asian financial crisis after Thailand abandoned its exchange-rate peg.
On July 2, 1997, Thailand allowed the baht to float after sustained pressure made its fixed exchange-rate system difficult to defend. The currency then fell sharply, and investors reassessed other Asian economies with large foreign debts, property bubbles, and vulnerable banking systems.
The turmoil spread to Indonesia, South Korea, Malaysia, and other markets. Stock exchanges declined, companies struggled to repay dollar-denominated loans, and the International Monetary Fund arranged support packages for several affected countries.
The crisis was not simply a stock-market event: currency devaluations and banking failures were central parts of it. The baht is the correct starting point, while the rupiah, won, and ringgit were currencies hit later or during the wider regional contagion.