An order block in LUSID is the grouping together, or blocking, of one or more similar orders, allowing you to place all of them in the market at once, or create multiple smaller placements for the block. Every order in LUSID must have a block associated with it. A block can be made up of one or many orders, and you can block orders created at different times.
For example, a Portfolio Manager might create one order for 100 AAPL US equity shares at 10:00am, and a separate order for 150 AAPL US equity shares just before midday. As a Trader, assuming the orders pass compliance checks, you might pick both of these orders up in the afternoon and block them together to create a block of 250 shares, ready to place.
There is no limit to the number of orders you can add to a block as long as they have the same:
LUSID Instrument ID (LUID).
Order side, for example whether the order is to buy or sell.
State, which must be “New”.
Order type, either market, limit or stop. If the order type is limit or stop, the price must also be equal to be able to add multiple orders to a block.
Time in force, that is, how long the order stays in effect.