Daily Price Limit
A daily price limit is a maximum amount by which the price of a futures contract (or certain equities) is permitted to rise or fall from the previous day's settlement price within a single trading session, established by the exchange as a circuit breaker to prevent disorderly markets, limit margin-induced liquidation cascades, and allow time for market participants to assimilate information during periods of extreme volatility.
Key takeaways
- When a futures contract reaches its daily price limit, trading is said to be 'limit up' or 'limit down'; in many cases, the market halts or severely restricts further trading at that price.
- Daily price limits exist primarily in commodity and financial futures markets; U.S. equity markets use percentage-based circuit breakers rather than futures-style price limits.
- A 'locked limit' condition—where price reaches the limit and no trades occur because all bids/offers are at the limit—can persist for multiple days during extreme events.
- Price limits can exacerbate illiquidity during crises by preventing price discovery and trapping participants unable to exit or adjust positions.
- Exchanges periodically review and expand price limits; after a limit is triggered, many exchanges automatically expand the limit for the following day.
Explanation
Daily price limits represent one of the oldest forms of exchange-based circuit breaker, predating electronic trading and electronic surveillance systems. They were developed in response to the agricultural futures market's tendency toward extreme price moves during supply disruptions, crop failures, and demand shocks, where the futures market's leveraged nature could amplify price dislocations far beyond economically justified levels. By capping daily price movement, exchanges aimed to prevent margin spirals—where price moves force margin calls, which force liquidations, which drive further price moves, and so on in a self-reinforcing cycle.
The mechanics of daily price limits vary by market and exchange. CME agricultural futures (corn, soybeans, wheat) use absolute dollar-per-bushel or dollar-per-metric-ton limits that expand over consecutive limit days. Energy futures (crude oil, natural gas) have had various limit structures that have evolved significantly over time. Equity index futures use percentage-based limits tied to S&P 500 levels, triggering brief trading halts (5–15 minutes) rather than full session halts. The specific limit amounts and expansion rules reflect the exchange's judgment about what constitutes a disorderly move versus genuine fundamental price discovery.
The theoretical debate over daily price limits centers on whether they enhance or impede market quality. Proponents argue that limits provide a 'cooling off' period allowing participants to reassess positions and information before further price discovery, reducing panic-driven overshoots and protecting risk management systems from instantaneous adverse moves. Critics argue that limits prevent rapid price adjustment to new information, creating artificial floors or ceilings that trap participants on the wrong side of positions and potentially concentrating market impact into the opening of the next session when limits are reset.
Historical episodes illustrate both perspectives. During the COVID-19 oil demand collapse in April 2020, crude oil futures (WTI May contract) went limit down multiple times before eventually settling at the famous negative $37.63 per barrel on April 20, 2020—a situation that arguably required price limits to be reconsidered, as the limit mechanisms initially slowed price discovery during an extraordinary fundamental dislocation. Conversely, during the 2022 nickel squeeze on the London Metal Exchange, the LME's decision to halt trading and cancel trades rather than let prices run freely demonstrated the exchanges' ongoing role in managing disorderly market conditions.
Formula
Locked Limit Condition: Market clears at Limit Price_t = Settlement Price_{t-1} ± Daily Price Limit_t; Position P&L = Δ(Settlement Price) × Contracts × Contract Size
Example
A corn futures trader holds 50 contracts (250,000 bushels) of December corn purchased at $5.50 per bushel. A surprise USDA crop report indicates a severe supply shortfall. The following morning, corn futures open at the daily price limit of $5.90 (limit up by $0.40). The market immediately goes 'locked limit up'—no sellers are willing to sell at $5.90 when the market would otherwise trade substantially higher. The trader cannot add to the position, but the existing long position shows a paper gain of $50,000 (250,000 × $0.40). Over the next two days, the market goes limit up again ($6.30) and again ($6.80 on an expanded limit of $0.50), ultimately finding equilibrium at $7.10 by day four when the limit expansion cycle is complete and buyers and sellers can transact freely.
Related terms
Anonymous Bidding Blind Auction Circuit Breaker Electronic Trading Equity Equity Index Exchange Futures Contract Iceberg Order Locked Limit Margin Market Impact