How do I handle different tax lot accounting conventions?

  • Updated on Oct 21, 2025
  • Published on Aug 20, 2024
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There are two ways in which you can set up tax lot accounting in LUSID:

  1. If your source system provides specific tax lot ("versus purchase") details on all transactions then you can specify sub-holding keys (SHKs) for a portfolio to segregate instrument-level holdings into tax lots. See below.

  2. If your source system doesn't always provide tax lot information then you can configure LUSID to calculate tax lots based on a standard algorithm at either the portfolio or a more granular level. More information.

Using SHKs to segregate holdings into tax lots

Loading data into LUSID

  1. Create a custom property in the Transaction domain to store the tax lot identifier.

  2. Create a transaction portfolio and register the property as a SHK.

  3. Book transactions into LUSID and specify a property value for each to nominate a particular taxlot.

Retrieving data from LUSID

Using this method, the following APIs return tax lots automatically:

  • GetHoldings API (and the Portfolio Management > Holdings dashboard in the LUSID web app).

  • GetValuation API (and the Portfolio Management > Valuations dashboard).

Having LUSID determine tax lots automatically

Loading data into LUSID

Set the accounting method to one of the supported tax lot accounting methods.

You can specify this for one of the following entities, or create a waterfall of logic by specifying it for all of them:

  1. On a transaction portfolio, using the accountingMethod field. The accounting method applies to every transaction in the portfolio, unless overridden below.

  2. On a movement within a transaction type, using the TransactionConfiguration/default/TaxLotSelectionMethod system property. The accounting method applies to every transaction of that type in any portfolio, overriding the setting for a particular portfolio.

  3. On a custodian account, using the accountingMethod field. The accounting method applies to every transaction in the account, overriding any settings for a transaction type or for a particular portfolio.

  4. On an individual transaction, using the Transaction/default/TaxLotSelectionMethod system property. The accounting method applies just to that transaction, overriding all other settings.

Retrieving data from LUSID

Using this method, the following APIs return tax lots in certain circumstances:

  • GetHoldings API (and the Portfolio Management > Holdings dashboard in the LUSID web app): Providing the byTaxlots parameter is specified, for example:

  • GetValuation API (and the Portfolio Management > Valuations dashboard): Providing no specific grouping is applied.