Preconditions
- You have placed a limit order on an exchange, and its current status is "Unfilled" or "Partially Filled".
- You can view the current best bid price and best ask price in the order book.
A limit order that perpetually almost fills happens because there is a small spread between your quoted price and the market's current lowest ask (for buys) or highest bid (for sells). Chasing the price means actively crossing this spread -- whether you should do it depends on the spread size and your position intent.
The core reason a limit order does not fill is the price priority and time priority rule: when your buy order price is lower than the current lowest ask, or your sell order price is higher than the current highest bid, your order enters the order book queue to wait. When you choose to "chase the price", you essentially give up the price advantage of the limit order and move your price closer to the market price.
Step 1: Measure how far your order is from being filled
[What to do]: Read the spread from the order book to quantify the exact value of that "almost filled" gap.
[How to do it]: Open the trading pair interface, locate the "Ask 1" (lowest sell price) and "Bid 1" (highest buy price). Compare your limit order price with Ask 1 / Bid 1 to calculate the gap.
Scenario A: Your buy order price is lower than Ask 1 → Spread = Ask 1 - Your buy order price. For example, if you place a 50,000 USDT buy order, and Ask 1 is 50,010 USDT, the spread is 10 USDT (0.02%). Scenario B: Your sell order price is higher than Bid 1 → Spread = Your sell order price - Bid 1. For example, if you place a 3,000 USDT sell order, and Bid 1 is 2,990 USDT, the spread is 10 USDT.
[Completion standard]: Get a specific spread percentage, such as 0.02% or 0.1%.
Step 2: Decide whether to chase the price based on spread size
[What to do]: Use a quantified threshold to decide to "chase" or "wait".
[How to do it]:
Scenario A: Spread < 0.05% (the normal range for major assets like BTC/ETH) → You can chase the price. Modify your limit order to the Ask 1 / Bid 1 price, and the order will fill immediately. Taking BTC as an example, a 0.05% spread equals roughly 25-30 USDT, which has minimal impact on positions with 5x or higher leverage. Scenario B: Spread ≥ 0.1% and lasts for more than 10 minutes → Chasing price is not recommended. This indicates insufficient market liquidity or rapid price volatility, and chasing may lead you to buy at a local high or sell at a local low. At this point, you should check if insufficient liquidity is causing order backlogs.
[Completion standard]: Reach a clear "chase" or "wait" decision based on the spread percentage.
High Risk Warning
Chasing price essentially turns your order into a "market-priced limit order" -- your execution price will be worse than your original limit price. If you chase price on low-liquidity altcoins, the spread can instantly expand from 0.1% to 0.5%-1%, directly erasing the expected profit of the trade. Before chasing price, you must check the 24-hour trading volume of the pair, and never chase price on pairs with volume below 1 million USD. (Source: Practical Trading Experience summary)
Step 3: Choose the right price chasing method based on your position intent
[What to do]: Choose different price chasing paths based on whether you need the order to fill immediately, or you are willing to wait for a better price.
[How to do it]:
Scenario A: You need to open/close the position urgently (you judge the market trend is about to start) → Cancel the existing order and place a market order directly. A market order fills immediately at the current optimal price, but you need to bear the slippage risk. Scenario B: You are not in a hurry to fill, but want to increase the fill probability → Use the "trailing limit order" (price chasing limit order) feature: set a maximum trailing distance, and your order price will dynamically adjust to follow the best bid/ask price until it fills or hits your maximum allowed distance. For example, if you set a 0.02% trailing distance for a buy order, your buy price will always be 0.02% lower than the current Ask 1, and move down synchronously as the market price drops.
[Completion standard]: After you execute the price chasing operation, the order status changes from "Unfilled" to "Filled" or "Partially Filled".
Common Failure Causes
When a limit order is almost filled, many people repeatedly tweak the price -- "it is 1 USD short so I raise it by 1 USD, then it is 1 USD short again so I raise it again". Each tweak refreshes the time priority of your order, pushing you to the end of the order queue. The correct approach is: either adjust your price all the way to Ask 1 / Bid 1 to fill immediately, or keep your original limit price and continue waiting. Frequent modifications will only make you stay at the back of the queue forever.
Post-Operation Verification Method
After chasing the price, check your "average fill price". If the difference between your execution price and original limit price is larger than the spread you observed before chasing (meaning slippage expanded), you should choose a more liquid trading pair or reduce price chasing frequency next time. If you used a trailing limit order, you can check in your order history whether the order was filled as a Maker (to enjoy lower transaction fees) via limit order records.
Next Follow-Up Actions
After your order fills, immediately check your "Open Orders" list for any remaining unfilled parts (common for partially filled orders). If there are leftover orders, cancel them manually to avoid unintended duplicate position opening. Verification rule: The "Status" column in your order history will show as "Fully Filled" or "Cancelled".
