An allocation in LUSID represents the distribution of fills to the one or more orders that form the block which was placed.
For example, as a Portfolio Manager, you might have previously created two orders for two different portfolios, which a Trader has placed: one order for 100 AAPL US equity shares and a second order for 150 AAPL US equity shares. Having received fills for all 250 shares, LUSID allocates 40% of the shares to Portfolio A and 60% to Portfolio B.
Allocations are continuously updated in LUSID as executions are received, meaning that fills can be allocated before the placement is 100% executed.
You can automatically allocate fills to your portfolios using two methods:
Allocating fills to portfolios based on the number of executions received back against the placements made.
Using more complex allocation algorithms. Read more on using LUSID's built-in allocation algorithms.
Once one or more fills are allocated to a portfolio, the allocation can be booked as (that is, converted into) a transaction at any time, or automated in a way that suits you, such as booking transactions at market close or when an order reaches 100% filled.