The Dow Jones Industrial Average’s largest one-day percentage fall during the October 2008 turmoil was 7.87%, recorded on October 15.
The decline came during the global financial crisis, when investors feared that the failure of major financial institutions and frozen credit markets would produce a deep worldwide recession. The Dow fell 733.08 points that session, its largest point decline at the time.
The October sell-off followed the September 2008 collapse of Lehman Brothers and the rescue of insurer AIG. Governments and central banks responded with emergency lending, bank recapitalizations, interest-rate cuts, and other stabilization measures.
The percentage loss is often confused with the much larger one-day percentage fall on October 19, 1987. The 2008 figure describes one session in a prolonged crisis, not the full decline from the market’s pre-crisis peak.