1987’s Selling Machine Is Back — 30x Bigger
On October 19, 1987, the Dow fell 22.6% (-508 points) in a single session — the largest one-day percentage drop in its history. It wasn’t just the news (trade deficit miss + takeover-tax bill the prior week). The Brady Commission found the crash was amplified by $60-90B of “portfolio insurance”: computer programs that automatically sold index futures as prices fell, feeding a loop — stocks fell, programs sold, stocks fell…








