TL;DRExchange-imposed circuit breakers that pause or halt trading when a contract's price moves beyond a predefined threshold. Designed to prevent panic-driven crashes and give the market time to absorb information.
Limit up and limit down are price thresholds set by the exchange that restrict how far a futures contract can move in a single session. If the price hits the limit down level, trading may be paused or halted to prevent further decline. If it hits limit up, the same happens on the upside.
These are circuit breakers designed to give the market a cooling-off period during extreme moves. They prevent panic selling (or buying) from feeding on itself and causing prices to disconnect from reality.
For equity index futures like ES, the CME uses a tiered system based on the prior day's settlement price. The levels are typically set at 7%, 13%, and 20% from the settlement.
At the 7% level (Level 1), trading is paused for 15 minutes during regular trading hours. At 13% (Level 2), another 15-minute pause. At 20% (Level 3), trading is halted for the remainder of the day.
During overnight (Globex) sessions, futures have their own separate price limits (typically 7% for ES) that prevent trading beyond those levels. Price can trade at the limit but not through it.
Commodity futures have different limit structures. Many agricultural and energy contracts use fixed-dollar or percentage-based limits that vary by product.
When a futures contract hits its price limit, several things happen. Liquidity evaporates on the side being tested. If ES hits limit down, there are no buyers at or below the limit. Sell orders stack up with no one to fill them.
When trading resumes after a pause, the market can gap further in the same direction or reverse sharply. The pause gives institutions time to reassess, but it doesn't guarantee a reversal.
If you have stop orders below a limit-down level, they cannot fill until trading resumes, and when it does, slippage can be severe. This is one of the scenarios where losses can significantly exceed your planned risk.
Level 1 circuit breaker
Major geopolitical news breaks overnight. ES drops 7% from the prior settlement during the Globex session.
ES hits its overnight limit-down level and cannot trade lower. Sellers who want out can only sell at the limit price if a buyer steps in. When RTH opens, a 15-minute pause may be triggered if the decline continues. During the pause, no trading occurs.
Stop order trapped below limit
You're long 2 ES with a stop at 5,100. ES hits limit down at 5,070 during the overnight session.
Your stop cannot fill because no trades can execute below 5,070. When the limit expands or regular trading resumes, ES may gap to 5,040. Your stop fills there, 60 points below your trigger price. That's $3,000 per contract in unexpected slippage.
Assuming your stop loss will always protect you
Stop orders cannot fill at prices below limit-down levels. In extreme events, your actual loss can be much larger than your planned stop. This is one reason to keep position sizes conservative.
Trying to buy the dip at limit down without understanding the risk
Buying at limit-down feels like a bargain, but the limit may expand further or the market may gap lower when trading resumes. Limit events are not normal market conditions.
Not knowing the circuit breaker levels for the product you're trading
Check the exchange website for current limit levels. They're recalculated daily based on the prior settlement and vary by product.