Which 1987 U.S. trading safeguard was introduced after the Black Monday crash?

The U.S. trading safeguard introduced after the Black Monday crash was circuit breakers. These rules are designed to pause trading when broad market prices fall by specified percentages, giving participants time to assess information and reducing disorderly selling.

The Brady Commission, formally the Presidential Task Force on Market Mechanisms, recommended coordinated safeguards after the October 19, 1987 crash. The New York Stock Exchange introduced market-wide trading halts in 1988. Modern U.S. rules use percentage declines in the S&P 500 to determine Level 1, Level 2, and Level 3 halts.

Circuit breakers do not prevent losses or guarantee that prices will recover. They temporarily interrupt trading under defined conditions, and separate mechanisms can address extreme moves in individual securities. Their design has changed over time, especially after later episodes such as the 2010 Flash Crash. The term “trading curbs” is related, but it can also refer more narrowly to restrictions on particular transactions.