# Facilitating matchmaking

* In order to kickstart liquidity on BullvBear, we have decided to limit the choices in terms of trading in our interface, limiting it in 3 ways :&#x20;
  * Limited [choice of collection](https://bullvbear.gitbook.io/home/understanding-the-protocol/facilitating-matchmaking/choice-of-collections), with only a few collections open for trading
  * Fixed [contract parameters](https://bullvbear.gitbook.io/home/understanding-the-protocol/facilitating-matchmaking/choice-of-option-parameters), with only one contract (Strike/Duration) available per collection at a given time
  * Fixed Settlement price and Security Deposit, defined and regularly updated by our [Automated Pricing Engine](https://bullvbear.gitbook.io/home/understanding-the-protocol/facilitating-matchmaking/automated-pricing-engine)
* Our key objective in doing so is to optimise the chances of matchmaking and have as many trades as possible on the platform.
* When users decides they want to trade on a contract, they are entered in our [order book](https://bullvbear.gitbook.io/home/understanding-the-protocol/facilitating-matchmaking/the-order-book) to be matched.
