To make the most of LUSID's bi-temporal event store and ability to back-date trades and corrections, it is important that you specify the appropriate creation date when you create a portfolio.
If you aren't familiar with LUSID's bi-temporal event store read about it here before continuing.
What is the significance of creation date?
When you create a portfolio inside LUSID two dates are important. These are the asAt date, which specifies when you actually made the call to LUSID and the created date, which specifies the activation point of the portfolio.
The asAt date cannot be altered; it is system generated. The created date by contrast is optional. If left out, it will default to the asAt, and if specified, an historic date can be supplied from which you may then upsert transactions.
For example if you created a portfolio today without specifying the 'created' parameter you would only be able to add transactions that are effective from today onward. You can see this represented in the diagram below.
Diagram 1: Creating a portfolio without specifying the 'created' parameter
However, with a current created date, there is no way to back-fill older transactions, so on-boarding existing portfolios would fail.
To overcome this you can set the 'created' parameter to be the date at which the portfolio first became active. For example, if our portfolio was first set-up in another system 3 years ago, you can pass this date as the 'created' parameter. As you can see in the diagram below this allows you to post the entire backdated transaction history, using effectiveAt dates to reflect when the transactions were executed.
Diagram 2: Creating a portfolio with a 'created' parameter of 3 years ago
You can see further details on how to create a portfolio with the 'created' parameter in our technical documentation.