Which 1998 hedge fund collapse triggered emergency action by the U.S. Federal Reserve?

The 1998 hedge fund collapse that triggered emergency action by the U.S. Federal Reserve was Long-Term Capital Management, commonly called LTCM. The fund suffered enormous losses after Russia's August 1998 debt default disrupted markets and correlations used in its trading models failed.

LTCM employed heavy leverage and traded complex positions across bonds, derivatives, and other markets. Because its counterparties were major financial institutions, an uncontrolled liquidation could have spread losses through the global financial system. The Federal Reserve Bank of New York facilitated meetings, but private-sector banks—not public money—organized a rescue consortium.

The episode was not itself a conventional stock-market crash, but it caused intense volatility and a flight from risk. The Federal Reserve cut interest rates in September, October, and November 1998. LTCM's failure became a major case study in leverage, model risk, and the danger of financial institutions whose positions are large relative to market liquidity.