In the 1998 Russian financial crisis, the Russian ruble was devalued and then allowed to float.
Russia had maintained a managed exchange-rate band, but falling oil prices, weak tax revenues, and heavy government borrowing made that policy increasingly difficult to defend. On August 17, 1998, the government and central bank widened the ruble's trading band, effectively devalued the currency, and announced a 90-day moratorium on some foreign debt payments.
The crisis damaged Russian banks and businesses and contributed to a sharp fall in domestic financial markets. It also helped bring down the hedge fund Long-Term Capital Management, whose positions were threatened by the turmoil. A common mix-up is to call this solely a stock-market crash: the episode combined currency devaluation, sovereign default, banking stress, and equity-market losses.