The following guide should be read in conjunction with the specific documentation from the broker or exchange involving these order types, lists/groups and execution instructions (such as for Interactive Brokers).

## Order Lists ¶

Combinations of contingent orders, or larger order bulks can be grouped together into a list with a common  order_list_id  . The orders contained in this list may or may not have a contingent relationship with each other, as this is specific to how the orders themselves are constructed, and the specific exchange they are being routed to.

## Contingency Types ¶

•  OTO  are parent orders with ‘one-triggers-other’ child orders.

•  OCO  are linked orders with  linked_order_ids  which are contingent on the other(s) (one-cancels-other when triggered).

•  OUO  are linked orders with  linked_order_ids  which are contingent on the other(s) (one-updates-other when triggered or modified).

Note

These contingency types relate to ContingencyType FIX tag <1385> https://www.onixs.biz/fix-dictionary/5.0.sp2/tagnum_1385.html .

### One Triggers the Other (OTO) ¶

An OTO orders involves two orders—a parent order and a child order. The parent order is a live marketplace order. The child order, held in a separate order file, is not. If the parent order executes in full, the child order is released to the marketplace and becomes live. An OTO order can be made up of stock orders, option orders, or a combination of both.

### One Cancels the Other (OCO) ¶

An OCO order is an order whose execution results in the immediate cancellation of another order linked to it. Cancellation of the Contingent Order happens on a best efforts basis. In an OCO order, both orders are live in the marketplace at the same time. The execution of either order triggers an attempt to cancel the other unexecuted order. Partial executions will also trigger an attempt to cancel the other order.

### One Updates the Other (OUO) ¶

An OUO order is an order whose execution results in the immediate reduction of quantity in another order linked to it. The quantity reduction happens on a best effort basis. In an OUO order both orders are live in the marketplace at the same time. The execution of either order triggers an attempt to reduce the remaining quantity of the other order, partial executions included.

## Bracket Orders ¶

Bracket orders are a type of advanced order that allows traders to set a take-profit and stop-loss level for a position at the same time. This is typically done by placing a parent order (also known as the entry order) and two child orders: a take-profit  LIMIT  order and a stop-loss  STOP_MARKET  order. When the parent order is executed, the two child orders are also placed in the market. If the market moves in favor of the trade, the take-profit order will be filled, closing the position and locking in profits. If the market moves against the trade, the stop-loss order will be filled, closing the position and limiting losses.

Bracket orders can be created using the OrderFactory class in the Nautilus Trader API. This allows for easy and efficient creation of bracket orders, with different order types, parameters and instructions.

Warning

You should be aware of the margin requirements of positions, as bracketing a position will consume more order margin.