Price limit rules
Price limit is one of the important risk control methods to protect investors and prevent the market from being manipulated. If there is no price limit, a few traders can make the contract price fluctuate greatly and create a large apportionment, by using a small amount of funds and a high leverage level. On the other hand, if the price limit rules are simple, it will lead to a lack of vitality in the market, and there will be no premium with the spot, and the contract trading will be meaningless.
In order to have a better risk control, the full rules of price limit are not completely disclosed. OKX will dynamically set risk control rules, based on more than a dozen parameters such as market trading volume, turnover, open interest, and the percentage of index deviation.
Contract price limit rules
Phase | Highest price limit | Lowest price limit |
|---|---|---|
Within 10 mins of contract generation | Index * (1 + X) | Index * (1 - X) |
10 mins after contract generation | Min[Max(Index, Index (1 + Y) + Avg. premium in last 2 mins), Index * (1 + Z)] | Max[Min(Index, Index * (1 - Y) + Avg. premium in last 2 mins), Index * (1 - Z)] |
For the details of X, Y, Z parameters, please visit: /trade-market/info/swap
Z equals 3% in 30 mins before weekly futures delivered.
The above parameters and indicators may be adjusted according to market conditions, and the adjustment will not be notified separately.
Remarks
Index: USDT-margined, USDC-margined and crypto-margined contracts refer to the index price of base currency as their index price.
E.g. BTCUSDT perpetual contract refers to the BTC/USDT index price, BTCUSDC perpetual contract refers to the BTC/USDC index price, BTCUSD perpetual contract refers to the BTC/USD index price.
Average premium in the past 2 minutes is calculated as follows:
Contract trading data per 200 milliseconds is obtained for the last 2 minutes, along with the spot index, and the mid-price per 200 milliseconds is calculated. Mid-price = (Best ask price + Best bid price) / 2. The mid-price minus the spot index is used as the premium basis per 200 milliseconds, and the average value of 600 premiums over the last 2 minutes is calculated.
The above rules apply to all contracts (including USDT, USDC and crypto-margined contracts). And there are also restrictions on opening and closing positions: when open a long position or close a short position, the order price is higher than the highest price; when open a short position or close a long position, the order price is lower than the lowest price, the limit price will be triggered.
Spot and margin price limit
These rules will apply to all spot and margin trades with spot indexes.
Phase | Highest price limit | Lowest price limit |
|---|---|---|
Within 10 mins of contract generation | No limit | No limit |
10 minutes after spot/margin listing | Highest price limit = Min [Max (Index, Index × (1 + y%) + Average premium in last 2 minutes), Index × (1 + z%)] | Lowest price limit = Max [Min (Index, Index × (1 – y%) + Average premium in last 2 minutes), Index × (1 – z%)] |
For details on the y and z parameters, refer to the following link: /trade-market/info/spot
The average premium in the last 2 minutes is calculated as follows:
Spot trading data per 200 milliseconds is obtained for the last 2 minutes, along with the spot index, and the mid-price per 200 milliseconds is calculated. Mid-price = (Best ask price + Best bid price) / 2.
The mid-price minus the spot index is used as the premium basis per 200 milliseconds, and the average value of 600 premiums over the last 2 minutes is calculated.
The preceding parameters and indicators may be adjusted according to market conditions, without separately issued announcements.
API users can refer to the following links: https://www.okx.com/docs-v5/log_en/#upcoming-changes-price-limit-rules-for-spot-and-margin-trading
Spot trading
Buy orders: Orders placed above the highest price limit will trigger the limit price rules.
Sell orders: Orders placed below the lowest price limit will trigger the limit price rules.
Margin trading
Opening positions: Long positions opened above the highest price limit and short positions opened below the lowest price limit will trigger the limit price rules.
Closing positions: Long positions closed below the lowest price limit and short positions closed above the highest price limit will trigger the limit price rules.
If limit price rules are triggered, the corresponding manually-placed orders will be adjusted to the price limit.
Spot and margin price protection
To protect users from large price slippages, your order will be cancelled if the filled price of exceeds a price limit.
Buy orders: Your order will be cancelled if the estimated filled price is greater than best ask price * 1.05.
Sell orders: Your order will be cancelled if the estimated filled price is lower than best bid price * 0.95.
Options price limit
OKX will dynamically set risk control rules based on options market price, Delta and other parameters. In order to make users better understand price limit, and convenient for users to trade, the highest price of buy order and lowest price of sell order are calculated as follows:
Highest price of buy order = Mark price of options + Adjustment coefficient * Max (0.004, 0.016 * abs (Delta));
Lowest price of sell order = Mark price of options - Adjustment coefficient * Max (0.004, 0.016 * abs (Delta));
OKX may adjust the above parameters according to certain market conditions, and the adjustment coefficients of different crypto options contracts are different. The limit price also needs to follow the smallest price unit requirement. Orders placed and forced reduction orders from common users also follow the price limit rules.