How often do circuit breakers trigger?

Rarely. They are designed for extreme days; the market-wide levels are measured from a daily reference and need a 7 percent fall of the S&P 500 to trigger the first halt.

Do crypto markets have circuit breakers?

Not market-wide ones like the US stock market. Individual crypto venues may apply their own price bands or protections, under their own rules.

Circuit breakers (market-wide halts)

Circuit breakers are coordinated trading halts and price limits designed to give markets a cooling-off period during large, fast declines. In the US stock market they trigger at 7, 13 and 20 percent falls of the S&P 500, the last one halting trading for the rest of the day, and CME's equity index futures limits are set to work alongside them.

Senzoukria · Glossary · Updated September 2026

Definition

The CFTC glossary describes circuit breakers as a system of coordinated trading halts and/or price limits on equity markets designed to provide a cooling-off period during large, intraday market declines. The best-known form is the market-wide mechanism of US stock exchanges, measured on the S&P 500.

The three levels

US market-wide circuit breaker levels, measured as a decline of the S&P 500
Level	Decline	Effect
Level 1	7 percent	Temporary market-wide halt
Level 2	13 percent	Temporary market-wide halt
Level 3	20 percent	Trading halted for the rest of the day

Worked example

If the reference level of the S&P 500 is 5,000.00, Level 1 is reached at 5,000 × 0.93 = 4,650.00, Level 2 at 5,000 × 0.87 = 4,350.00 and Level 3 at 5,000 × 0.80 = 4,000.00. CME's equity index futures limits use the same percentages during regular hours, which is why the futures and the stock market halt around the same levels.

Circuit breakers and futures

Equity index futures limits are coordinated with the stock market levels during regular hours.
Outside regular hours the futures have their own overnight limit and no stock market is open to halt.
Other exchange controls, such as velocity logic, pause individual futures for seconds on much smaller, faster moves.

In Senzoukria

No halt detection is built in. The market clock covers the scheduled CME calendar, open, daily break and weekend, but a halt in the middle of a session appears as a chart that stops receiving trades. The connection diagnostic warns that a quiet feed and a broken feed look the same on screen, which is exactly the situation during a halt.

Common mistakes

Believing futures are halted overnight at the same levels as the stock market.
Confusing a market-wide circuit breaker with a single-product pause such as velocity logic.
Restarting connections during a halt and concluding the platform is broken.

In the same section

Sources

CFTC glossary (2026-09-25)

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Frequently asked questions

How often do circuit breakers trigger?: Rarely. They are designed for extreme days; the market-wide levels are measured from a daily reference and need a 7 percent fall of the S&P 500 to trigger the first halt.
Do crypto markets have circuit breakers?: Not market-wide ones like the US stock market. Individual crypto venues may apply their own price bands or protections, under their own rules.

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