Contents
Definition
A circuit limit (also called a price band or circuit filter) is a regulatory mechanism that restricts or halts trading when a security's price moves beyond a preset percentage from its reference price (usually prior day's close) during a trading session. SEBI mandates circuit limits to prevent extreme volatility, panic-driven crashes, and manipulation-driven spikes. There are two types: scrip-level price bands (apply to individual stocks) and index-level circuit breakers (apply to the entire market). Source: SEBI Circular CIR/MRD/DP/25/2013; SEBI F&O Circular SEBI/HO/MRD2/DCAP/CIR/P/2021/616.
How It Works Mechanically
Scrip-level price bands (individual stocks): SEBI assigns each stock a price band of ±2%, ±5%, ±10%, or ±20% based on stock characteristics (index constituent, liquidity, volatility history). Stocks in the F&O segment (Nifty 200 + select others) have no daily price band because their circuit protection comes from the index-level breaker. When a stock hits its upper circuit (UC) limit, only buy orders at exactly that price can be placed — no sell orders at higher prices are accepted. The order book stacks up on the buy side with no sellers. Similarly, at the lower circuit (LC), only sell orders accumulate with no buyers. The stock remains "locked" at the circuit until the next trading day unless the exchange intervenes.
Index circuit breakers (Nifty 50/Sensex based) per SEBI Circular CIR/MRD/DP/25/2013:
- 10% movement: Market halt for 45 minutes (if triggered before 1 PM); 15 minutes (1–2:30 PM); no halt (after 2:30 PM).
- 15% movement: Market halt for 1 hour 45 minutes (before 1 PM); 45 minutes (1–2 PM); remainder of day (after 2 PM).
- 20% movement: Trading halted for remainder of trading day.
During an index circuit halt, all cash and derivatives trading on NSE and BSE stops simultaneously. The halt is coordinated between exchanges.
Cost Components
Circuit limits themselves carry no direct cost. Indirect costs when a circuit is hit:
- Orders queued at upper/lower circuit may not execute — opportunity cost if price gaps further next day.
- Brokers may require higher margins for stocks frequently hitting circuits (elevated volatility = higher VAR margin).
- For F&O positions on index, a 10% index circuit halt means all open positions carry overnight risk if the halt extends to end-of-day.
Risk / Protection Rules
- Dynamic price bands: NSE applies a dynamic ±1%/±2% intra-day band around a short-term reference price (last traded price) for F&O stocks, in addition to the broad circuit. This prevents flash crashes from erroneous orders.
- Surveillance Action (Stage I–IV): SEBI CIPAS and exchange surveillance can move a stock to ASM (Additional Surveillance Measure) or GSM (Graded Surveillance Measure) frames, reducing its price band to ±2% or ±5%, even if it was previously ±20%.
- Exclusion of F&O stocks: Stocks in the F&O segment have no scrip-level band (effective band is ~60% via dynamic bands) because price discovery through derivatives requires wider movement.
- SME stocks: NSE Emerge and BSE SME stocks have ±5% circuit limits unless specifically reviewed.
Worked Example
Hypothetical scenario: Adani Enterprises is not in the F&O segment on a given date. Previous close: ₹2,400. Circuit band: ±20%. Upper circuit: ₹2,880; Lower circuit: ₹1,920. Following a surprise positive announcement, the stock rises rapidly to ₹2,880 at 10:15 AM — it hits the upper circuit. Trading is not halted; instead, only buy orders at ₹2,880 are accepted. Thousands of buy orders queue; sellers are absent. The stock remains "locked UC" the rest of the day. Next day's reference price is ₹2,880, new band: upper ₹3,456 / lower ₹2,304. Index circuit example: Nifty 50 falls 10.5% by 11:30 AM — all trading halted for 45 minutes.
Caveats / Common Mistakes
- Stocks hitting upper circuits for multiple consecutive days accumulate a huge order imbalance — the eventual selling, when the UC unlocks, can be severe.
- Retail investors can mistake "locked UC" as a sign of guaranteed further gains. The opposite is possible if the news reverses or promoters sell into the queue.
- Dynamic intra-day bands can trigger temporary pauses in F&O stocks that look like circuit triggers — these are usually 15-minute cooling-off halts, not full-day locks.
See Also
Primary Source
MintByte (ARN-314872 / APMI APRN-01658) provides this glossary for educational purposes only. Nothing here constitutes investment advice, a recommendation to buy or sell any security, or a guarantee of returns. Equity and derivatives trading involves risk of loss. Consult a SEBI-registered adviser before making investment decisions.