> For the complete documentation index, see [llms.txt](https://docs.prophetmarket.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.prophetmarket.ai/reference/fees-spread-and-gas.md).

# Fees spread and gas

*Exactly what trading costs, and who pays for what.*

Prophet does not charge a separate commission line. The cost of trading is the spread, which is already inside the prices you are quoted, and the only other costs you face are external to Prophet entirely.

| Cost             | Who pays | When it applies                                          |
| ---------------- | -------- | -------------------------------------------------------- |
| Trading spread   | You      | Every trade. Already baked into the displayed price.     |
| Polygon gas      | Prophet  | Every on chain action. You never need to hold MATIC.     |
| Bridging fee     | You      | Cross chain deposits only. Deducted by the bridge route. |
| Source chain gas | You      | Cross chain deposits only. External to Prophet.          |

## The spread

The spread is the gap between the price to buy and the price to sell. Prophet earns that gap, functioning much like a currency exchange booth that quotes one rate to buy and a slightly worse rate to sell.

**The cost of a round trip**

```
Buy YES at 65¢          you pay      65¢
Sell YES at 63¢         you receive  63¢
```

Cost of entering and exiting without any price movement: 2¢ per share.

{% hint style="danger" %}
**The spread is substantial**

Prophet's spread is currently around twenty percent, and the rate may be adjusted depending on the risk profile of a market. This is the single largest cost of using Prophet and it should shape how you trade. Check the buy and sell prices on any market before sizing a position.
{% endhint %}

Two practical conclusions follow. First, short holding periods are expensive, because you pay the spread twice regardless of how brief the trade was. Second, your view needs to be wrong by less than the spread for a trade to be worth making, which means marginal opinions are not tradeable and strong disagreements are.

## Gas

Prophet absorbs all Polygon gas so you never need to hold the network's gas token. This is a real cost that Prophet pays on your behalf to keep the experience clean, and it applies to every on chain action including trades, redemptions and withdrawals.

{% hint style="success" %}
**You only ever need USDC**

There is no second token to acquire, no gas balance to top up, and no failed transaction because you ran out of MATIC.
{% endhint %}


---

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