# Fee Breakdown
### Opening Fee
A one-time opening fee is charged when a position is opened, designed to cover the cost of initiating trades **without charging again on close**. This fee is a flat rate for traditional (non-crypto) assets—e.g., a 4 bps fee, equivalent to 2 bps open + 2 bps close on other platforms—kept simple and predictable. More details [here](https://ostium-labs.gitbook.io/ostium-docs/ostium-trading-engine/opening-trades#protocol-opening-fee).
{% hint style="info" %}
There is a $0.10 upfront oracle fee for closing positions manually, which is entirely refunded after the trade is executed. Automated close orders (SL/TP) do not incur such a fee.
{% endhint %}
All pairs are subject to a fixed opening fee, regardless of leverage or Open Interest skew.
***
## Oracle Fee
A flat **$0.10** fee charged whenever the protocol must fetch and attest an external price (oracle read) to process your action. This covers oracle and automation costs.\
For market **opens**, if the transaction reaches chain and fails for any reason, the oracle fee is still charged. The front end blocks most failure cases except **slippage**, so slippage is the most common reason you might see a fail with the fee consumed.
### When the oracle fee is charged (and refunded or not)
| Action | Charged | Refunded | Notes |
| ------------------------------------- | ------- | ---------------------- | ------------------------------------------------------------------------------------------------------------------------------------- |
| Open **market** order | Yes | No | If the open fails (including due to **slippage**), collateral is returned but the oracle fee is consumed. |
| Open **limit** order (place) | Yes | No | Charged when placing the limit order. |
| **Cancel** limit order | — | No | Collateral is returned, but the fee paid at placement is not refunded. |
| **Partial close** | Yes | No | Charged per partial-close execution. |
| **Remove collateral** (reduce margin) | Yes | No | Charged per request. |
| **Full close (100%)** | Yes | **Yes, if successful** | Fee is charged upfront and **refunded** on a successful full close. If the close fails (e.g., slippage), the fee is **not** refunded. |
***
### Liquidation Fee
If a position is liquidated, the trader’s remaining collateral is seized and paid out as a negative PnL to the Vault. More details [here](https://ostium-labs.gitbook.io/ostium-docs/ostium-trading-engine/closing-trades#liquidation).
***
### Price Impact
Orders execute at the underlying bid or ask price based on the order’s side and type, unless the pair has **Dynamic Spreads** enabled—in which case execution occurs at the **Price-After-Impact**, a dynamically adjusted price that reflects real-time liquidity conditions and short-term order flow balance. Click [here](https://ostium-labs.gitbook.io/ostium-docs/dynamic-spreads) to learn more.
***
### Rollover Fee
The rollover fee reflects underlying market carry costs, and is applied to all assets.
* Charges may differ by side
* Fees compound per block and are factored directly into unrealized PnL
* Rollover fees are realized when the position is closed
This fee covers the cost of carrying positions over time. More details [here](https://ostium-labs.gitbook.io/ostium-docs/broken-reference).
The rollover fee is displayed on the Net Rate (L/S) label. Hover over it to display a tooltip explaining the long/short rollover fees.
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