Circuit Breakers & Trading Halts
Understanding Market Circuit Breakers
Circuit breakers are automatic trading halts triggered when markets fall too fast. They were created after Black Monday 1987 to prevent panic cascades. The idea: pause trading for 15 minutes, let people breathe, prevent margin calls from forcing more selling, and stabilize the market.
The logic is sound. The execution is messy for options traders.
S&P 500 Circuit Breaker Levels
There are three levels of circuit breakers on the S&P 500. They're calculated based on the opening price of the index each day.
| Level | Decline % | Action | Duration |
|---|---|---|---|
| Level 1 | 7% | Market-wide halt, all trading stops | 15 minutes |
| Level 2 | 13% | Market-wide halt, all trading stops | 15 minutes |
| Level 3 | 20% | Market-wide halt, market closes for remainder of day | Remainder of day (closes at 4pm) |
Example: If the S&P 500 opens at 4,000, a 7% decline would be 280 points (4,000 × 0.07). If it falls to 3,720, trading halts for 15 minutes. After 15 minutes, trading resumes at 3,720. If it then falls to 3,480 (13% from open), another 15-minute halt. If it reaches 3,200 (20% from open), the market closes for the day.
Individual Stock Halts: LULD Bands
Beyond the market-wide circuit breakers, individual stocks have their own halts based on LULD: Limit Up Limit Down. These are price bands set by FINRA that prevent stocks from moving too far too fast.
How LULD Works
Each stock is assigned a band, typically 5%, 10%, or 20% of its recent price. For a $100 stock with a 5% band:
- Upper limit (limit up): $105. Trading halts if bid goes above this.
- Lower limit (limit down): $95. Trading halts if ask goes below this.
If a stock hits its limit down and orders flow in to sell at $94, the trade is rejected. The stock must rebound back to $95 before trading can occur. This prevents pennies-per-share cascades.
During panics, stocks frequently hit limit down. On March 16, 2020, major stocks like XOM, CRM, and others halted multiple times during the day, hitting limit down, then recovering to limit up, then back to limit down again.
EEM (emerging markets ETF) at market open: $36
5% LULD bands: $34.20 (limit down) to $37.80 (limit up)
9:35am: Panic selling forces EEM to $34.20, hits limit down, halts
9:50am: After 15 min, trading resumes, EEM bounces to $35.50
9:51am: More selling hits, EEM back to $34.20, halts again
Traders with short puts were trapped in repeated halt cycles with no ability to exit.
What Happens to Your Options During a Halt
Core Rule: You Cannot Trade
When a market-wide halt triggers, options exchanges halt. You cannot place orders, cancel orders, or execute anything. Your position is frozen. This is the key risk.
You have a short $220 put spread. Stock is at $215 (your spread is max loss). Trading halts at 10:15am. You cannot exit, cannot reduce, cannot do anything. You wait 15 minutes.
At 10:30am, trading resumes. The stock might be at $210 or $225. But until then, you're locked in.
The Bid-Ask Catastrophe
When trading resumes after a halt, bid-ask spreads explode. A stock that had a 1-cent spread before the halt might have a 50-cent or wider spread after.
For options, this is worse. Your short put spread that was worth $0.50 pre-halt might have a $0.30 bid, $0.80 ask after reopening. If you want to exit, you're taking the $0.80 ask, losing $30 per spread in the reopen.
Gap Risk: The Unhedgeable Problem
Between halts, the market can gap. You're short $290 puts on a stock. Before halt, stock at $292. Halt triggers, 15 minutes pass, trading resumes... stock opens at $285. Your puts are now ITM, your spread is wider, and you're max loss before you even knew it.
There is no hedge for this. You cannot short call spreads simultaneously because that would be even larger position size. You cannot buy further OTM insurance because that adds cost. This is pure tail risk.
Managing Existing Positions During Halts
Pre-Halt Preparation
Never hold risky overnight positions when you know a negative catalyst is possible. Before earnings, Fed meetings, or geopolitical events, close out short premium by market close. Don't let your positions sit overnight with tail risk hanging.
Real example: August 5, 2011. Debt ceiling was resolved, but markets opened sharply lower on concerns. S&P 500 fell fast. Level 1 circuit breaker triggered. Traders who had sold strangles overnight got destroyed because they couldn't exit through the halt.
Intra-Halt Position Management (Nothing You Can Do)
During a halt, there is literally nothing to do. Your broker will show "market is halted." You cannot place any orders. This is the time to take a breath, get water, and prepare for the reopen.
What NOT to do: Panic-sell at market on the reopen. Often, the reopen is a relief bounce. A stock that fell 8% to the halt price might reopen flat or up. If you panic-sell, you're selling to a recoved market.
Post-Halt Decisions
After halt, trading resumes. Your position might be worse, the same, or even better (less common, but rallies happen). Now you decide:
Option 1: Exit at any cost. If your position size is large relative to your account, take the spread and exit. Better to lose $1,000 than risk $5,000.
Option 2: Hold and manage. If your position is small and the thesis is intact, hold. Use the following 15 minutes to reassess.
Option 3: Add insurance (size-dependent). If you're short puts, consider buying further OTM puts to cap max loss. This costs premium but buys peace of mind.
Circuit Breaker History: March 2020
The Unprecedented Quad-Halt Day
Monday, March 9, 2020. COVID-19 fears, oil price war between Russia and Saudi Arabia, and general panic. What happened:
9:33am: Market opens, immediately down 7.4%. Level 1 circuit breaker triggers. Trading halts.
9:49am: Trading resumes after 15 minute halt. Relief bounce, market rallies 3%.
2:47pm: Afternoon selling brings market back to -13% from open. Level 2 circuit breaker triggers.
3:02pm: Trading resumes. Market falls again.
3:15pm: Another -7% decline from the previous close triggers a Level 1 halt (it resets after recovery).
3:31pm: Final halt of the day expires. Market closes at 4pm.
Trader with short call spreads: Bought back spreads at levels after 2nd halt, took $5,000 loss
Trader with short put spreads: Held through halts, closed at reopen prices, took $12,000 loss
Trader with long call spreads: Bought at day low (after 2nd halt), sold into reopen relief, made $8,000
Lesson: If you're going to hold options through halt risk, make sure your position benefits from volatility compression or recovery, not from further decline.
Limit Up Limit Down and Individual Stock Halts
When LULD Matters for Options
A stock hits limit down. Its options cannot be traded because the underlying cannot be traded. Your options spread is frozen. You cannot close it.
If you have a short put spread on that stock, and the stock is limit down below your short strike, you're at risk of max loss if the stock gaps further and there's no reopen at a better price.
Pre-Market and After-Hours Implications
Options trade only during market hours. Pre-market (4am-9:30am) and after-hours (4pm-8pm) do not have full options liquidity. If bad news breaks after-hours, options cannot be traded to hedge.
Example: A company announces bankruptcy after 4pm. Options market is closed. You're short puts on that stock. Overnight, the stock might fall 50%. When options reopen at 9:30am, those puts are worth pennies. You're assignment risk on thousands of shares at bankruptcy prices.
Strategy: Do not hold short options on anything announcement-adjacent (earnings, FDA decisions, merger votes) through close. The concentration of risk between market close and next open is not worth the premium.
Preparing for Potential Halts
Position Sizing for Halt Risk
If you have 50 contracts of short options, and a halt occurs, and your position gaps against you by 2 standard deviations, your max loss is potentially $5,000+ (50 contracts × $100 width).
Can you afford that without liquidating other positions or going into margin? If not, your position size is too large for halt risk.
A safer approach: If you're selling spreads with a $1,000 max loss per spread, limit to 10 spreads during high-risk periods. During calm markets, you can scale to 20+.
Diversification Across Time
Don't have all your positions expire on the same day. If you have 20 spreads, have 5 expiring each week. This way, if there's a halt early in the week, you still have flexibility later in the week.
Always Have an Exit Plan
Before entering any trade, know your exit: 50% max profit, 21 DTE, or when VIX rises above 30. Having a pre-set rule prevents panic decisions during halts and stress.
Key Takeaways
- Level 1 (7%), Level 2 (13%), Level 3 (20%) are S&P 500 circuit breaker thresholds triggering 15-min halts or full market close.
- Individual stocks have LULD bands (typically 5%, 10%, 20%) that can halt individual stocks without market-wide halts.
- During a halt, you cannot trade. Period. Your position is frozen.
- Bid-ask spreads explode on reopen, making exits expensive.
- Gap risk is unhedgeable; the only protection is smaller position size.
- Never hold overnight short options before announcement-heavy days or major events.
- March 2020 saw 4 halts in one day; traders with smaller positions survived; those with large positions got destroyed.