> ## Documentation Index
> Fetch the complete documentation index at: https://docs.roxom.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Pre-Trade Order Controls

> Roxom employs comprehensive pre-trade and post-trade risk controls to maintain market integrity and protect traders from abnormal events.

* **Fair Mark Pricing:** As discussed, Roxom uses a **Mark Price** derived from external indices for all margin and liquidation calculations. This isn't exactly a "control" on trades, but it's a fundamental risk principle: traders are not liquidated or margined off possibly manipulated last prices.
* **Price Band Limits (Pre-Trade):** To avoid absurd or fat-finger prices, Roxom sets **price bands** around the current market price for each contract. By default, no order can be placed more than **±50%** away from the current Mark Price of the contract. If a user submits an order with a price beyond these bands, the system will automatically reject it. *(Each contract can have its own band threshold; 50% is the default. Specific instruments might have tighter bands* [*specified in their specs*](/rulebook/our-contracts-offering-and-specs/gold-btc)*).*
* **Maximum Order Size (Pre-Trade):** Roxom imposes a limit on the size of any single order to prevent an individual order from being so large that the market cannot safely absorb it. If a user tries to place an order larger than the allowed cap, the system will reject it. The specific **order size caps** are calibrated per instrument liquidity and can be adjusted by Roxom's risk committee as needed. At launch:
  * **Market Order Size Cap:** **0.5 BTC** notional per single market order, *and* the trade is limited by the slippage impact cap (as per instrument specs) as described earlier. Essentially, a market order will not execute more than 0.5 BTC worth, or beyond 2% price impact, whichever condition hits first. This prevents a single market order from consuming too much order book depth.
  * **Limit Order Size Cap:** **0.5 BTC** notional per single limit order. Although limit orders add liquidity rather than taking it, Roxom still caps them to manage risk. A large limit order does not immediately move the market; in fact, it can help stabilize the order book by providing depth.