What was the name of the 1998 hedge fund that collapsed due to high leverage and Russian debt default?

The hedge fund that collapsed in 1998 was Long-Term Capital Management, commonly abbreviated LTCM.

Founded in 1994, LTCM pursued relative-value and convergence trades: it sought to profit when related securities moved back toward historically typical price relationships. Its partners included prominent traders and Nobel Prize-winning economists Myron Scholes and Robert Merton, which helped create an aura of exceptional mathematical expertise.

The strategy depended on small price differences, so the fund used enormous leverage to magnify returns. That approach failed when markets moved together in unexpected ways. Losses began before Russia's August 17, 1998, default, then intensified as investors fled risky and less-liquid assets and the prices of LTCM's positions diverged further.

LTCM lost about $4.6 billion and faced the danger of forced liquidation across global markets. On September 23, the Federal Reserve Bank of New York organized a $3.625 billion rescue financed by major creditors. The Fed did not directly bail out the fund; it helped coordinate a private-sector recapitalization to limit possible contagion. LTCM was eventually wound down.