On July 2, 1997, the Bank of Thailand abandoned its long-standing peg of roughly 25 baht to the US dollar and allowed the currency to float. Within a day the baht had fallen about 20 percent. Within six months it had lost more than half its value. What began as a single-country currency adjustment spread within weeks into Indonesia, South Korea, Malaysia, and the Philippines, and within a year had reshaped how investors thought about emerging-market exposure. The episode remains one of the clearest illustrations of how currency mismatch, capital flow reversal, and contagion interact to turn a localized problem into a regional one.
A Currency Peg Breaks
Throughout the 1990s, several Southeast Asian economies pegged their currencies to the US dollar while running large current account deficits and allowing domestic banks and corporations to borrow heavily in dollars. This arrangement worked as long as capital kept flowing in and the peg held credibly. Thailand's problem was structural: short-term foreign debt had grown to roughly 100 billion dollars against foreign reserves of around 30 billion by mid-1997. When speculative pressure mounted and reserves were depleted defending the peg, the central bank had no option but to let it go. The mechanism is generalizable: a fixed exchange rate backed by finite reserves is only as durable as the willingness and ability of a central bank to keep defending it.
Capital Flows Reverse
The years before 1997 had seen enormous portfolio and bank lending inflows into the region, drawn by growth rates often exceeding 7 percent annually and by yield-seeking behavior in a low-rate global environment. Once the baht floated, foreign lenders and investors reassessed risk across the entire region simultaneously, not just in Thailand. Capital that had flowed in over years left in months. This is the sudden-stop dynamic later studied extensively by economists such as Guillermo Calvo: inflows that appear stable can reverse abruptly once confidence shifts, and the reversal itself becomes self-reinforcing as falling currencies increase the local-currency cost of dollar debts.
Contagion Across Borders
By late 1997 the Indonesian rupiah had fallen more than 80 percent against the dollar, the Korean won had dropped sharply enough to trigger an International Monetary Fund program of 58 billion dollars in December 1997, and the Malaysian ringgit and Philippine peso were both under heavy pressure. The MSCI Emerging Markets Asia index fell by roughly 60 percent in US dollar terms between mid-1997 and its trough in 1998. Hong Kong's currency board came under speculative attack in August 1998, prompting its monetary authority to intervene directly in equity markets, purchasing roughly 15 billion dollars of local shares to counter what it described as a coordinated assault on the currency and stock market together. The contagion did not require identical fundamentals across countries; investors reduced exposure to the region as a category, illustrating how correlation among seemingly distinct markets can rise sharply during periods of stress.
The IMF Response and Its Costs
Rescue packages were assembled for Thailand (17.2 billion dollars, August 1997), Indonesia (over 40 billion dollars across revisions), and South Korea, typically conditioned on fiscal tightening, interest rate increases, and structural reforms to banking systems. These programs were controversial at the time and remain debated among economists, since tightening policy during a liquidity crisis arguably deepened the initial downturn in output and employment before conditions stabilized. Indonesia's economic and political crisis culminated in President Suharto's resignation in May 1998 after three decades in power, a reminder that financial crises can carry consequences well beyond asset prices.
A Measured Recovery
The recovery, when it came, was uneven but real. South Korea's KOSPI index, which had fallen from above 800 in 1994 to roughly 280 by late 1998, more than tripled over the following decade. Countries that undertook banking sector cleanups and built larger foreign exchange reserve buffers afterward, including South Korea, Thailand, and Malaysia, generally proved more resilient in subsequent global downturns, including 2008. The crisis also prompted a broader shift across emerging Asia toward floating exchange rates, current account surpluses, and substantially larger reserve holdings, changes still visible in regional economic policy today.
Generalizable Lessons for Long-Term Investors
Several patterns from 1997 recur across later episodes. Currency mismatch, where revenues are earned in one currency and debts are owed in another, has repeatedly proven to be a hidden source of fragility that balance sheets alone do not reveal. Capital flows that appear stable during calm periods can reverse with little warning once sentiment shifts, and emerging-market diversification carries currency risk that is distinct from, and sometimes larger than, the underlying equity risk. Correlation across ostensibly unrelated markets tends to rise during acute stress, reducing the diversification benefit investors may have assumed they held. Finally, policy responses that look harsh in the moment, such as the IMF's conditionality, often reflect a tradeoff between short-term pain and longer-term structural repair, a tension that resists easy judgment even decades later.
The rule to internalise
Fixed exchange rate regimes and foreign-currency borrowing can work smoothly for years before failing abruptly, and the transition from calm to crisis in such systems has historically been faster and more interconnected than conditions beforehand would suggest. Understanding where currency, debt, and capital flow risks are concealed within a portfolio or an economy has mattered more, historically, than trying to anticipate the exact timing of any single break.
Educational content only. Not investment advice.