Circuit breaker

Also called: Price band, Circuit filter, Upper circuit, Lower circuit · Topic: Financial Markets, Instruments, Insurance and Pensions · NCERT: Beyond NCERT

Meaning

A circuit breaker is an automatic rule that stops trading on the whole stock market for a fixed time when a major index, the Sensex or the Nifty 50, rises or falls by 10%, 15% or 20% in one day [2][3]. A related rule, the price band (also called a circuit filter), works on single shares. It sets a daily limit, and a share cannot trade outside that range.

• Why it matters: in a crash, fear spreads fast. One sale leads to more panic selling. The pause lets investors stop, think and get fresh information before trading starts again.
• Trigger in points: 10%, 15% or 20% × the index's closing level in the previous quarter. The result is rounded to the nearest 25 points for the Sensex and the nearest 10 points for the Nifty [2].

Explanation

1. Market-wide (index-based) circuit breaker: how it works

• What sets it off: the Sensex or the Nifty 50 moves 10%, 15% or 20%, up or down. Whichever index crosses the limit first triggers it [2][3].
• What happens: trading stops across the market. The length of the halt depends on how big the move is and what time it happens:

Move	When it happens	Halt
10%	Before 1 PM	1 hour
10%	1 PM to 2:30 PM	30 minutes
10%	At or after 2:30 PM	No halt
15%	Before 1 PM	2 hours
15%	1 PM to 2 PM	1 hour
15%	At or after 2 PM	Rest of the day
20%	Any time	Rest of the day

• The logic behind the table:
• A bigger move means a bigger shock, so the halt is longer.
• A 10% move late in the day gets no halt, because the market closes soon anyway.
• A 20% move is treated as extreme, so trading stops for the rest of the day at any time.

2. From percentages to index points

• The limits are not checked as live percentages during the day. They are fixed in index points every quarter, based on the index's closing level in the previous quarter [2].
• Rounding: Sensex limits are rounded to the nearest 25 points and Nifty limits to the nearest 10 points [2].
• Worked example: suppose the Nifty closed the last quarter at 25,000.
• 10% trigger = 0.10 × 25,000 = 2,500 points
• 15% trigger = 0.15 × 25,000 = 3,750 points
• 20% trigger = 0.20 × 25,000 = 5,000 points
• Suppose the Nifty falls 2,500 points before 1 PM. Trading then stops for 1 hour.

3. Stock-level price bands (upper and lower circuit)

• Price band = a daily limit on how far one share's price can move. The limit is 2%, 5%, 10% or 20%. The share cannot trade outside its band that day.
• Upper circuit = the share has reached the top of its band. Buyers are waiting, but no one will sell at a price inside the band.
• Lower circuit = the share has reached the bottom of its band. Sellers are waiting, but no one will buy at a price inside the band.
• Worked example: a share closed yesterday at ₹200 and has a 10% band.
• Today it can trade only between ₹180 and ₹220.

• If it reaches ₹220, it is "locked in the upper circuit".

• Key difference: the market does not stop. Only that share's price is capped.

4. Why prices hit these limits

• Panic selling after wars, pandemics, political instability or sudden policy changes can lead to a stock market crash (the share prices of many companies falling steeply at the same time).
• Company news, such as a big loss, a strike or a very good result, can push one share to its upper or lower circuit.
• Fast automated trading: algorithmic trading and HFT (high-frequency trading, where computer programs place huge numbers of orders in fractions of a second) can make a price move much bigger within seconds. Limits act as a brake.

In India

• Regulator: SEBI sets the circuit breaker rules. They were set out in its circular on the index-based market-wide circuit breaker in compulsory rolling settlement (June 2001) [2]. They were updated by the index-based market-wide circuit breaker mechanism circular (January 2015) [3].
• Exchanges: BSE (Sensex, 30 stocks) and NSE (Nifty 50, 50 stocks) apply the halt. A move in either index is enough to trigger it [2][3].
• Quarterly reset: the trigger levels in points are recalculated every quarter from the previous quarter's close [2].
• Real case, March 2020: during the COVID crash, the market-wide circuit breaker was triggered and trading was halted.
• Why it matters more now: more small investors are in the market. Demat accounts (accounts that hold shares in electronic form) grew from 7.38 crore in October 2021 [4] to more than 21.6 crore in FY26 (till December 2025) [6]. Many of these are first-time investors, and panic spreads among them quickly.

Don't confuse with

• Stock price band vs market-wide circuit breaker: a price band caps one share's price at 2%, 5%, 10% or 20%, and the rest of the market keeps trading. A market-wide circuit breaker stops all trading when the Sensex or Nifty 50 moves 10%, 15% or 20%.
• India VIX: the VIX only measures expected near-term volatility, and it is worked out from Nifty option prices. It is the "fear gauge". A circuit breaker acts: it stops trading.
• Correction and bear market: these describe how far prices have fallen. A correction is usually a fall of about 10%. A bear market is commonly a fall of 20% or more from a peak, lasting a long time. A circuit breaker is a same-day trading rule, not a name for a market trend.
• Stock market crash: a crash is the event, a steep fall in many shares at once. The circuit breaker is the tool that slows the crash down.

Prelims Hooks

• The market-wide circuit breaker is triggered by a 10%, 15% or 20% move in the Sensex or the Nifty 50, whichever is breached first [2][3].
• A 20% move halts trading for the rest of the day, whatever the time. A 10% move at or after 2:30 PM causes no halt.
• Trap: it works both ways. A sharp rise can trigger it, not only a fall.
• The trigger levels in points are reset every quarter from the previous quarter's close. Sensex limits are rounded to the nearest 25 points and Nifty limits to the nearest 10 points [2].
• Stock-level price bands are 2%, 5%, 10% or 20%. A share at its band limit is at its "upper circuit" or "lower circuit". Trading in other shares does not stop.
• Trap: SEBI makes the rules. The exchanges (BSE and NSE) carry them out. The market-wide breaker was triggered in March 2020 (COVID crash).

Mains Points

• Calm the market vs let prices find their level:
• Halts stop panic from spreading and give time for information to reach everyone. This protects small investors.
• But a halt also stops price discovery (buyers and sellers setting a fair price). Investors may be unable to sell when they most need to.

• Critics say that as prices get close to the limit, traders may rush to trade before the halt, and this can speed up the move.

• Safety valves in a faster market:

• Algorithmic trading, HFT and faster settlement (T+1, optional T+0 from 21 March 2024 [1]) mean prices, and shocks, move faster.

• Circuit breakers, price bands and the VIX together act as the market's safety valves. They work alongside SEBI's 2025 retail algo framework [7].

• Investor protection as households move into shares:

• Demat accounts rose above 21.6 crore (FY26) [6], and the BSE market cap-to-GDP ratio was 136% in December 2024 [5]. More household savings are now exposed to market swings.
• Circuit breakers limit panic losses in a single day. They do not replace financial literacy or SEBI's other investor-protection work.

Related concepts

• Secondary market
• Depository
• Demat account
• Clearing corporation
• T+1 settlement
• Algorithmic trading
• Sensex
• Nifty 50
• Market capitalisation
• Free float

Read more

• Secondary market: trading infrastructure, indices and valuation