A stop tells the system when to submit an order. It does not promise the price you will receive
A stop price is a trigger. A fill price is an execution result.
Those two numbers can match, but they do not have to.
The difference matters most in fast markets, thin order books and gaps. A trader can set a stop at one level, see it trigger correctly and still receive a different average fill.
That is not automatically a system error. It is how the order moves from a condition into the market.
What a stop order actually does
A stop order waits for a specified trigger price.
On Hyperliquid, take-profit and stop-loss orders are triggered using the mark price. Once the trigger condition is met, the system submits the chosen order type. The final execution then depends on the order book.
The sequence is:
The mark price reaches the trigger.The stop condition activates.A market or limit order is submitted.The order trades against available liquidity.One or more fills create the average execution price.
The trigger answers “when should the order become active?” The fills answer “what liquidity was available after it became active?”
Stop-market and stop-limit solve different problems
Stop-market
A stop-market order prioritises execution.
Once triggered, it can trade across the available order book. If the market is moving quickly, the order may fill at several prices. The average can be worse than the trigger.
That difference is slippage.
Stop-limit
A stop-limit order gives you more control over the acceptable price.
Once triggered, it places a limit order. The order will not trade beyond the limit you chose. The trade-off is that it may fill only partly, or not at all, if the market moves through the limit too quickly.
This is a choice between execution certainty and price control. Neither option guarantees both.
A concrete example
Suppose a long position has a stop trigger at $100.
The mark price reaches $100 and activates a stop-market sell. At that moment, the best bids are:
2 units at $99.903 units at $99.705 units at $99.40
A 10-unit order can fill across all three levels. The average fill is $99.58, even though the trigger was $100.
Now imagine a stop-limit order with a $99.80 limit. It can sell 2 units at $99.90, but the remaining 8 units cannot trade below $99.80. They stay open unless cancelled or the price returns.
The stop-market exited the full position at a worse average price. The stop-limit protected the price but left exposure behind.
Why the last price can mislead you
The last traded price is a record of one completed trade.
It does not show the quantity available for your next order. It also may not be the price used to trigger the stop.
Before blaming a mismatch, compare:
the mark price at the triggerthe order type submitted after the triggerthe order sizethe bids or asks available at executionthe individual fills, not only the final average
That evidence tells you whether the stop triggered correctly and how the order actually traded.
Build the stop before you need it
Do not make this decision while the market is already moving against you.
Before placing the order, decide:
which price should trigger itwhether full execution or a price limit matters morehow large the order is relative to visible liquiditywhat partial execution would leave in the accounthow you will verify the fills afterward
A stop is a risk tool, not a price guarantee.
In Fensory, review the live price, order controls and current market conditions before submitting an order. If you later investigate an outcome, use the order and fill records rather than relying on one chart marker.
Trading involves risk, including the loss of funds. This article is educational and is not financial advice.
Sources
Hyperliquid take-profit and stop-loss ordersHyperliquid trade outcome FAQHyperliquid order types
Stop price and fill price are not the same number was originally published in Coinmonks on Medium, where people are continuing the conversation by highlighting and responding to this story.