Locked Limit
A locked limit is a market condition in futures trading where a contract has reached its maximum allowable daily price move (the price limit) and trading in that contract effectively ceases because all orders are at the limit price with no counterparty willing to transact on the other side—buyers are willing to buy at the limit price (limit up) but sellers will not sell at that price, or vice versa.
Key takeaways
- A locked limit differs from a regular limit move in that not only has the price limit been reached, but the order book is completely one-sided: only buyers exist at limit-up, or only sellers at limit-down.
- During a locked limit, open positions cannot be offset through normal trading, trapping market participants in their existing positions and potentially causing cascading margin calls.
- Consecutive locked limit days—when the same contract hits its limit multiple sessions in a row—create severe risk management challenges and can threaten clearing house solvency in extreme cases.
- Exchanges may temporarily expand or eliminate price limits after one or more locked-limit sessions to allow prices to find their equilibrium, though this exposes all participants to potentially extreme moves.
- Physical-delivery contracts that are locked limit approaching delivery dates present particular risks, as shorts may be unable to buy back positions before being required to make delivery.
Explanation
A locked limit condition arises from the confluence of a price limit mechanism and an overwhelming one-sided order imbalance. In a standard limit-move scenario, trading continues at or within the limit price—buyers and sellers who agree to transact at the limit or closer to the previous close can still execute. In a true locked-limit scenario, the market is effectively frozen: every participant with an open long position wants to exit but cannot (locked limit down), or every participant with an open short position wants to cover but finds no sellers (locked limit up).
The locked-limit condition is most dangerous during multi-day sequences. Imagine a commodity contract—say, lean hogs futures—that experiences a catastrophic supply disruption. The contract may hit its daily limit (say, $0.04/lb up) for three, five, or even ten consecutive sessions. During these sessions, short sellers cannot exit their positions regardless of their willingness to pay the limit price—there are simply no sellers willing to transact at the exchange's maximum permitted price. Each night, margin calls are calculated at the limit price, even though shorts cannot liquidate to meet those calls. If the shorts lack sufficient margin capital and cannot obtain it, the clearing house must cover the difference, creating systemic risk.
The operational response to locked limit conditions varies by exchange and severity. CME Group's standard procedure expands the daily limit if a contract settles at or near the limit for a specified number of consecutive days: for example, if the normal limit is $0.40/bushel for corn, it might be expanded to $0.60 after one locked-limit day and to $0.80 after two. If the market continues to trade at the expanded limit, further expansion (or complete removal of limits) may occur. The theory is that the initial limit provides a cooling-off period and allows participants to arrange capital, but persistent locked-limit conditions indicate that the limit is too tight to allow market clearing.
For risk managers and clearing houses, locked limit conditions require special protocols. Daily settlement prices during a locked-limit session are set at the limit price itself, even though this may not reflect the true market clearing price. Variation margin calculations based on this artificial settlement price may understate or overstate the actual losses that would be realized if trading could occur. Clearing houses maintain emergency liquidity facilities and may call for additional default fund contributions from clearing members when multiple large participants are simultaneously unable to meet margin calls during a locked-limit sequence.
The interaction between locked limits and short squeezes is notable. A heavily shorted commodity or financial contract that suddenly faces a genuine fundamental shock (weather disaster, regulatory change, supply disruption) may experience a locked-limit-up condition that prevents short sellers from covering—a short squeeze intensified by the limit mechanism. This amplifies the losses for short sellers beyond what would occur in a liquid market where they could exit at a high but finite price.
Example
In early March 2022, London Metal Exchange (LME) nickel futures experienced a locked-limit condition of dramatic proportions. A major Chinese commodity trader (Tsingshan Holding Group) held an enormous short position in nickel of approximately 150,000–200,000 tonnes (roughly 15,000–20,000 futures contracts). A short squeeze began as nickel prices rose sharply on fears of supply disruption from the Russia-Ukraine war. In a single day (March 8, 2022), nickel prices doubled from approximately $29,000/tonne to over $100,000/tonne—a move that would have cost the short seller billions of dollars. The LME suspended nickel trading, cancelled billions of dollars of trades made on March 8th, and implemented daily price limits. The locked-limit and subsequent trading halt illustrated how price limits, while designed to prevent disorderly markets, can themselves become a source of market dysfunction when the underlying market imbalance is severe.
Related terms
Blind Auction Clearing Cover Default Exchange Limit Move Liquidity Margin Matching Algorithm Settlement Short Squeeze Squeeze Short Squeeze