KEY POINTS
  • The Dow Jones Industrial Average plummeted 22.6 percent on Oct. 19, 1987, also known as "Black Monday," which amounted to 507.99 points at the time.
  • A 22.6 percent plunge on the 30-stock Dow today would amount to a 5,735.76-point loss. For context, the biggest one-day point loss on the Dow took place on Feb. 5, when it closed down 1,175.21 points.
Picture taken October 19, 1987 shows a trader holding his head on the floor of the New York Stock Exchange when the Dow Jones dropped over 500 points, the largest decline in modern time, as panic selling swept Wall Street.

Friday marked the 31st anniversary of "Black Monday," by far the worst day ever in the U.S. stock market.

On that day — Oct. 19, 1987 — the Dow Jones Industrial Average plummeted 22.6 percent, or 507.99 points at the time. If that kind of plunge were to happen today, the point loss would be far worse.