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Circuit Breaker

Circuit Breaker

What Is a Circuit Breaker?

The term "circuit breaker alludes" to an emergency-utilize regulatory measure that briefly halts trading on an exchange. Circuit breakers endeavor to curb in alarm selling and can likewise be set off on the way up with hyper purchasing. They are regularly utilized for individual securities as well as broad market indexes like the S&P 500. Circuit breakers function naturally by halting trading when prices hit predefined levels in exchanges around the world.

How Circuit Breakers Work

A circuit breaker functions in the trading world the same way it accomplishes for electrical circuits in a home. At the point when things get over-burden, it kicks in and closes down the circuit. In trading, circuit breakers are emergency measures laid out by stock markets that shut down trading activity for a brief time or until the end of the trading day when market prices drop essentially. As verified over, this system applies to both individual securities and market indexes.

Since February 2013, there have been far reaching circuit breakers that answer single-day declines in the S&P 500 index. At the point when the index falls by 7% below its previous close, it is viewed as a Level 1 decline. A Level 2 decline alludes to a drop of 13%. At long last, a Level 3 decline alludes to a drop of 20%. These levels have not changed as of March 2022.

Level 1 or 2 circuit breakers halt trading on all exchanges for 15 minutes except if they are set off at or after 3:25 PM (in which case trading is permitted to proceed). Level 3 circuit breakers halt trading until the end of the trading day (from 9:30 a.m to 4:00 p.m.).

Dissimilar to their far reaching partners, circuit breakers for individual securities are set off whether the price goes up or down. Exchange-traded funds (ETFs) are treated as individual securities under the circuit breaker system, even however they address arrangement of several securities.

Since all securities are halted when certain levels are set off, they are known as all inclusive circuit breakers.

Special Considerations

The table below frames the acceptable trading ranges used to control individual securities inside the current system of circuit breakers. Assuming that trading outside of these bands perseveres for 15 seconds, activity is halted for five minutes. The reference price is calculated utilizing the average price over the previous five minutes yet the maximum permitted stop is 10 minutes.

To oblige the higher volumes generally associated with the opening and closing periods of the trading day, the bands are multiplied throughout the previous 25 minutes.

Since May 31, 2012, the Securities and Exchange Commission (SEC) has utilized a limit-up limit-down (LULD) mechanism to determine the thresholds for acceptable trading. In this system, halts are set off by up-or-down moves outside of certain bands, determined based on the security's price and listing.

Key Parameters of the Circuit Breaker System
Acceptable up-or-down trading range (9:30 am-3:35 pm)Acceptable up-or-down trading range (3:35-4:00 pm)Security price, listing
5%10%Tier 1 National Market System (NMS) Securities; S&P 500- and Russell 1000- listed stocks, some exchange-traded products; Tier 2 Symbols priced below $3.00; price greater than $3.00 (price > $3.00)
10%20%Tier 2 NMS Securities (except for rights and warrants); other stocks priced over $3.00 (p > $3.00)
20%40%Other stocks priced greater than or equal to $0.75 and less than $3.00 ( $0.75 ≤ p ≤ $3.00)
Lesser of 75% or $0.15Lesser of 150% (upper limit only) or $0.30Other stocks priced less than $0.75 (p < $0.75)
Circuit breakers are brought into effect assuming that trading happens outside of these predefined boundaries.

Source: Limit Up Limit Down

History of Circuit Breakers

Regulators put the initial circuit breakers into place following the market crash that happened on Oct. 19, 1987. On this day, the Dow Jones Industrial Average (DJIA) shed 508 points-falling by roughly 22.6%-in a single day. The crash, which started in Hong Kong and before long affected markets worldwide, came to be known as Black Monday.

A second episode, the supposed flash crash of May 6, 2010, saw the DJIA drop very nearly 1,000 points and bounced back minutes after the fact. Prices generally recuperated by the market close, yet the disappointment of the post-1987 circuit breakers to halt the crash made the regulators update the circuit breaker system around then.

Analysis of Circuit Breakers

A few analysts accept that circuit breakers are disruptive and keep the market falsely volatile since they make orders build at the limit level and decline liquidity. Pundits of circuit breakers contend that assuming that the market were permitted to move uninhibitedly, with no halts, they would settle into a more steady equilibrium.

Certifiable Example of a Circuit Breaker

A recent illustration of circuit breaker activity happened with quick succession of four halts on March 9, March 12, March 16, lastly on March 18, 2020. On both of nowadays, circuit breakers were set off at the New York Stock Exchange (NYSE). In one occasion, the S&P 500 fell over 7% at the open, logical in response to the seriousness of the becoming global coronavirus pandemic.


  • The principal circuit breaker was put into place after the Dow Jones Industrial Average dropped almost 23% on Oct. 19, 1987.
  • Circuit breakers for individual securities are set off whether prices go up or down.
  • The current system of circuit breakers has been updated several times based on feedback from past emergencies.
  • U.S. regulations have three levels of a circuit breaker, which are set to halt trading when the S&P 500 Index drops 7%, 13%, and 20%.
  • Circuit breakers are impermanent measures that halt trading to curb alarm selling on stock exchanges.


What Happens at Each Breaker Level Threshold?

On the off chance that a Level 1 or Level 2 circuit breaker is set off, trading halts for at least 15 minutes. A Level 3 breach halts trading until the end of the trading day.

Are Options Markets Also Halted When a Circuit Breaker Is Triggered?

Indeed, in the event that the equities market sets off a circuit breaker, trading in the impacted listed options markets is likewise halted. Any trades that happen after the halt are invalidated.

When Is a Market-Wide Circuit Breaker Triggered?

Extensive circuit breakers are set off when the broad-based S&P 500 falls by a certain amount inside a single trading day, which halts trading across all markets. It tends to be set off at three circuit breaker thresholds relative to the prior day's closing price of the S&P 500, The first is Level 1 at 7%, trailed by Level 2 at 13%, and 20% at Level 3. The purpose of circuit breakers is to stem excess market volatility.

Are the Rules the Same for Single-Stock Circuit Breakers?

No, under SEC rules, a stock is required to go through a trading stop on the off chance that the stock price climbs or down outside the price band (5%, 10% or 20%) inside a five-minute period. These rules fluctuate contingent upon the price of the stock and whether it is a Tier 1, Tier 2, or different NMS listed security.