---
title: "What is a system property?"
slug: "what-is-a-system-property"
updated: 2026-07-21T09:15:19Z
published: 2026-07-21T09:15:19Z
canonical: "support.lusid.com/what-is-a-system-property"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://support.lusid.com/llms.txt
> Use this file to discover all available pages before exploring further.

# What is a system property?

A system property is a built-in function belonging to a particular type of entity that can either be read-only or writable:

| **Category** | **Enables you to...** | **Example** |
| --- | --- | --- |
| Read-only | Retrieve system information from LUSID that may not be available through other mechanisms. | `Transaction/default/SourcePortfolioId` You can retrieve this system property for transactions in a derived portfolio and LUSID reveals the original portfolio in which each transaction is booked. |
| Writable | Record data that LUSID can then use in valuation and other business operations. | `Transaction/default/TradeToPortfolioRate` You can add this system property to transactions with values that record exchange rates for those traded in a different currency, enabling LUSID to maintain the cost basis of the portfolio in the base currency |

You can interact with system properties in much the same way as the [custom properties](/v1/docs/properties) you create to extend the LUSID data model. System properties have a 3-stage key consisting of a domain, scope and code in exactly the same way, though note the underlying system property *types* are opaque.

## Retrieving system properties for entities

To retrieve a system property, decorate it onto entities of the appropriate type when you retrieve the latter [in the same way as a custom property](/v1/docs/how-do-i-retrieve-a-property-or-derived-property-for-an-entity). For example, to decorate `Transaction/default/SourcePortfolioId` onto transactions retrieved from one of the LUSID demonstration portfolios:

```json
curl -X GET "https://<your-domain>.lusid.com/api/api/transactionportfolios/Finbourne-Examples/UK-Equities/transactions?propertyKeys=Transaction%2Fdefault%2FSourcePortfolioId"
  -H "Authorization: Bearer <your-API-access-token>"
```

> **Note**: FINBOURNE reserves the right to change the underlying format and data type of system properties, so retrievals at different times may yield different results.

## Adding writable system properties to entities

To add a writable system property, enter the property key and a value when you upsert an entity of the appropriate type [in the same way as a custom property](/v1/docs/how-do-i-add-a-property-to-an-entity). For example, to use `Transaction/default/TradeToPortfolioRate` to record the USD/GBP rate for a USD transaction in one of the GBP-denominated demonstration portfolios:

```json
curl -X POST "https://<your-domain>.lusid.com/api/api/transactionportfolios/Finbourne-Examples/Global-Equity/transactions"
  -H "Authorization: Bearer <your-API-access-token>"
  -H "Content-Type: application/json-patch+json"
  -d '[{
  "transactionId": "01",
  "type": "Buy",
  "instrumentIdentifiers": {
    "instrument/default/Figi": "BBG000C6K6G9"
  },
  "transactionCurrency": "USD",
  "properties": {
    "Transaction/default/TradeToPortfolioRate": {
      "key": "Transaction/default/TradeToPortfolioRate",
      "value": {
        "metricValue": {
          "value": 0.73,
          "unit": "
        }
      }
    }
  },
  ...
}]'
```

## Transaction system properties

Note you can only use transaction system properties with [transactions](/v1/docs/adding-system-properties-to-transactions-and-to-transaction-types) (not other types of entity).

| **System property key** | **Writable?** | **Data type** | **Explanation** |
| --- | --- | --- | --- |
| `Transaction/default/BondInterest` | YES | Number | Stores the bond interest bought or sold when buying or selling fixed income instruments. |
| `Transaction/default/TradeToPortfolioRate` | YES | Number | Stores the exchange rate between the transaction currency and the portfolio base currency. |
| `Transaction/default/GrossConsideration` | YES | Number | Stores the gross consideration, which is the total consideration plus any fees. Note both gross consideration and total consideration are in [settlement currency](/v1/docs/how-is-cost-calculated-in-lusid#understanding-the-implications-of-transaction-currencies), not transaction currency. |
| `Transaction/default/TotalFees` | YES | Number | Stores total fees when LUSID's [transaction fee engine](/v1/docs/transaction-fees-and-capitalisation) is enabled, both capitalised and expensed. |
| `Transaction/default/TotalCapitalisedFees` | YES | Number | Stores total capitalised fees. |
| `Transaction/default/TotalNonCapitalisedFees` | YES | Number | Stores total expensed fees. |
| `Transaction/default/OriginalTradeDate` | YES | String | Overrides the transaction date when creating a new tax lot. This is mainly used for 'transfer'-type transactions; that is, the transfer is recorded with a transaction date of ‘today’ but it's an investment you've held for ten years, and you want to preserve the 'days held'. |
| `Transaction/default/OriginalSettlementDate` | YES | String | As above, but for the settlement date. |
| `Transaction/default/TaxLotSelectionMethod` | YES | String | Overrides the [tax lot accounting method](/v1/docs/what-are-the-supported-tax-lot-accounting-methods-in-lusid) set either on the portfolio, transaction type or custodian account. |
| `Transaction/default/PriorityTaxLots` | YES | Array of strings | Replaces (or partially replaces) the [tax lot accounting method](/v1/docs/what-are-the-supported-tax-lot-accounting-methods-in-lusid) for a transaction that reduces a position in a holding in order to dispose of particular tax lots as a priority. Specify an array of tax lot IDs, for example `["TL-2", "TL-6", "TL-9"]`. Note that the incumbent accounting method is used if the priority lots cannot meet the requirement. So for example if the accounting method set on the portfolio is FIFO and there are three lots: - `TL-1`: 100 units - `TL-2`: 100 units - `TL-3`: 100 units Then a `Sell` transaction for 250 units with priority lots set to `["TL-2"]` first liquidates `TL-2`, then `TL-1`, and then 50 units from `TL-3`. |
| `Transaction/default/AllocationMethod` | YES | String | Set the value to `Prorated` to override the default behavior (either built-in to LUSID or set on the transaction type) and prorate a transaction that itself has no sub-holding keys across all sub-holding keys defined for the portfolio. This is typically useful where a transaction represents a single coupon or dividend payment but the investment is held in multiple strategies. |
| `Transaction/default/RequiresFundingLegHistory` | YES | String | Set the value to `True` to override the default behavior and indicate that the instrument being transacted is a funding leg. |
| `Transaction/default/NotionalAmount` | YES | Number | Stores the notional amount of a buy or sell transaction in a [future](/v1/docs/modelling-exchange-traded-futures-and-options-in-lusid) or [CFD](/v1/docs/modelling-cfds-in-lusid) instrument. |
| `Transaction/default/PortfolioId` | NO | String | For a transaction in a portfolio group, retrieves the code of the portfolio in which it is booked. |
| `Transaction/default/PortfolioScope` | NO | String | As above, but retrieves the portfolio scope. |
| `Transaction/default/SourcePortfolioId` | NO | String | For a transaction in a derived transaction portfolio, retrieves the code of the original portfolio in which it is booked. |
| `Transaction/default/SourcePortfolioScope` | NO | String | As above, but retrieves the portfolio scope. |
| `Transaction/default/TxnInputType` | NO | String | For a transaction booked with a transaction type that is aliased to a source, retrieves the original transaction type. For example, transactions from SourceA might have a BUY transaction type, those from SourceB have an ACHETER type, and both are aliased to a PURCHASE type that is set as the default source: \| **Type** \| **Units** \| **Source** \| **Transaction/default/TxnInputType** \| \| --- \| --- \| --- \| --- \| \| PURCHASE \| 100 \| SourceA \| BUY \| \| PURCHASE \| 200 \| default \| \| \| PURCHASE \| 300 \| SourceB \| ACHETER \| |
| **Type** | **Units** | **Source** | **Transaction/default/TxnInputType** |
| PURCHASE | 100 | SourceA | BUY |
| PURCHASE | 200 | default |  |
| PURCHASE | 300 | SourceB | ACHETER |
| `Transaction/default/ResultantHolding` | NO | Number | For a transaction booked with a transaction type that itself has a movement with a ‘security’ side (that is, concerned with instruments and units), retrieves the current holding. For example: \| **Type** \| **Units** \| **Transaction/default/ResultantHolding** \| \| --- \| --- \| --- \| \| PURCHASE \| 100 \| 100 \| \| PURCHASE \| 200 \| 300 \| \| SELL \| 250 \| 50 \| |
| **Type** | **Units** | **Transaction/default/ResultantHolding** |
| PURCHASE | 100 | 100 |
| PURCHASE | 200 | 300 |
| SELL | 250 | 50 |
| `Transaction/default/InvestmentScalingMetadata` | NO | String |  |
| `Transaction/default/CounterpartyAgreementId` | NO | String |  |
| `Transaction/system/SourceInstrumentId` | NO | String |  |
| `Transaction/system/SourceInstrumentId` | NO | String |  |
| `Transaction/system/AppliedTaxRule` | NO | String | Retrieves the tax rule in a tax rule set that LUSID applied to an activity such as a corporate action based on matching property values. [More information](/v1/docs/calculating-dividend-tax-and-reporting-it-as-a-separate-cash-balance#tax-rule-set). |

## Transaction type system properties

Note you can only use transaction type system properties with [transaction types](/v1/docs/adding-system-properties-to-transactions-and-to-transaction-types#transaction-types) (not other types of entity).

| **System property key** | **Writable?** | **Data type** | **Explanation** |
| --- | --- | --- | --- |
| ***On the transaction type itself*** |
| `TransactionConfiguration/default/CashFlowType` | YES | String | Overrides the cash flow type associated with a particular transaction type. By default, LUSID's cashflow generation tool (the [GetUpsertablePortfolioCashFlows](https://www.lusid.com/docs/api#operation/GetUpsertablePortfolioCashFlows) API) generates a set of upsertable transactions with the built-in `CashFlow` transaction type. If you would prefer LUSID to assign a different transaction type to a particular upsertable transaction based on the cash flow type emitted by the underlying instrument, apply this property to that transaction type and give it one of the following cash flow type values: \| **Cash flow type** \| **Explanation** \| \| --- \| --- \| \| `Premium` \| A premium. \| \| `Coupon` \| A coupon payment. Distinct from a premium in that a coupon would be paid for a bond or rates leg whereas as a premium would be paid on an insurance-related product such as a credit default swap. \| \| `Notional` \| A notional-related flow, such as a notional exchange. \| \| `Principal` \| A payment of principal, typically return of principal. \| \| `Protection` \| A payment as a result of a default event on a credit protection leg. \| \| `Cash` \| A cash payment resulting from an option or settlement of an option. \| For example, an interest rate swap transaction emits a cash flow type of `Coupon`. You could assign a property with this value to a transaction type that specifies a more sophisticated set of movements more appropriate to an IRS than `CashFlow`. For an example, see the life cycle section of [this Jupyter Notebook](https://github.com/finbourne/sample-notebooks/blob/master/examples/use-cases/instruments/Interest%20Rate%20Swap.ipynb). |
| **Cash flow type** | **Explanation** |
| `Premium` | A premium. |
| `Coupon` | A coupon payment. Distinct from a premium in that a coupon would be paid for a bond or rates leg whereas as a premium would be paid on an insurance-related product such as a credit default swap. |
| `Notional` | A notional-related flow, such as a notional exchange. |
| `Principal` | A payment of principal, typically return of principal. |
| `Protection` | A payment as a result of a default event on a credit protection leg. |
| `Cash` | A cash payment resulting from an option or settlement of an option. |
| `TransactionConfiguration/default/AllocationMethod` | YES | String | Set the value to `Prorated` to override the default behavior and prorate all the transactions of this transaction type that have no sub-holding keys across all sub-holding keys defined for the portfolio. This is typically useful where transactions represent a single coupon or dividend payment but investments are held in multiple strategies. Note you can override this for an [individual transaction](/docs/what-is-a-system-property#transaction). For an example, see [this Jupyter Notebook](https://github.com/finbourne/sample-notebooks/blob/master/examples/features/core-lusid/Sub-holding%20Keys.ipynb). |
| `TransactionConfiguration/default/InstrumentEventType` | YES | String | Set the value to `transitionEvent/Dividend` to use this transaction type for corporate actions automatically determined by LUSID to be cash dividends. By default, LUSID applies the built-in `Dividend` transaction type to corporate actions representing cash dividends, which has the effect of increasing the main cash balance by the dividend amount, minus any tax due if a tax rule set applies. For example, you may want to override `Dividend` and specify your own transaction type in order to process tax differently. [See an example](/v1/docs/calculating-dividend-tax-and-reporting-it-as-a-separate-cash-balance). |
| ***On a movement within the transaction type*** |
| `TransactionConfiguration/default/TaxLotSelectionMethod` | YES | String | Overrides the default [tax lot accounting method](/v1/docs/what-are-the-supported-tax-lot-accounting-methods-in-lusid) set on the portfolio. Note you can override this for an [individual transaction](/v1/docs/what-is-a-system-property#transaction-system-properties). |

## Holding system properties

| **System property key** | **Writable?** | **Data type** | **Explanation** |
| --- | --- | --- | --- |
| `Holding/default/TaxlotPurchaseDate` | NO | DateTime | Retrieves the date on which a set of assets was purchased. |
| `Holding/default/TaxlotPurchasePrice` | NO | Decimal | Retrieves the price paid in the portfolio currency for the set of assets purchased. |
| `Holding/default/TaxlotId` | NO | String | Retrieves a unique identifier for each taxlot, using the identifier of the transaction that set up the taxlot. |
| `Holding/default/SourcePortfolioId` | NO | String | For a holding in a portfolio group, retrieves the code of the portfolio to which it belongs. |
| `Holding/default/SourcePortfolioScope` | NO | String | As above, but retrieves the portfolio scope. |

## Portfolio system properties

Note you can only use portfolio system properties with [portfolios](/v1/docs/portfolios) (not other types of entity).

| **System property key** | **Writable?** | **Data type** | **Explanation** |
| --- | --- | --- | --- |
| `Portfolio/default/ModelFees` | YES | Number | Stores fees for LUSID to use when calculating aggregated returns. |
| `Portfolio/default/AnnualReturnAdjustment` | YES | Number | Stores adjustments for LUSID to use when calculating aggregated returns. |
| `Portfolio/default/FundFamily` |  |  |  |
| `Portfolio/default/ConstituentAnnualReturnAdjustment` | YES | Number | Stores adjustments for constituents in a benchmark for LUSID to use when calculating aggregated returns. |

## Instrument system properties

Note you can use instrument system properties with transactions and holdings as well as [instruments](/v1/docs/instruments).

| **System property key** | **Writable?** | **Data type** | **Explanation** |
| --- | --- | --- | --- |
| `Instrument/default/Name` | NO | String | Retrieves the display name of the instrument. |
| `Instrument/default/Scope` | NO | String | Retrieves the scope in which the instrument is mastered. |
| `Instrument/default/BloombergExchangeCode` | NO | String | Retrieves the Bloomberg exchange code. |
| `Instrument/default/LusidInstrumentId` | NO | String | Retrieves the automatically-generated LUID identifier. |
| `Instrument/default/ClientInternal` | NO | String | Retrieves the ClientInternal market identifier. |
| `Instrument/default/MicCode` | NO | String | Retrieves the market identifier code for the exchange. |
| `Instrument/default/Currency` | NO | String | Retrieves the ISO 4217 currency code. |
| `Instrument/default/Isin` | NO | String | Retrieves the Isin market identifier. |
| `Instrument/default/Cusip` | NO | String | Retrieves the Cusip market identifier. |
| `Instrument/default/Sedol` | NO | String | Retrieves the Sedol market identifier. |
| `Instrument/default/RIC` | NO | String | Retrieves the RIC market identifier. |
| `Instrument/default/Ticker` | NO | String | Retrieves the Ticker market identifier. |
| `Instrument/default/CompositeFigi` | NO | String | Retrieves the CompositeFigi market identifier. |
| `Instrument/default/ShareClassFigi` | NO | String | Retrieves the ShareClassFigi market identifier. |
| `Instrument/default/Figi` | NO | String | Retrieves the Figi market identifier. |
| `Instrument/default/WertPapier` | NO | String | Retrieves the Wertpapier market identifier. |
| `Instrument/default/QuotePermId` | NO | String | Retrieves the QuotePermId market identifier. |
| `Instrument/default/EdiKey` | NO | String | Retrieves the EdiKey market identifier. |
| `Instrument/default/LookThroughPortfolioId` | NO | String |  |
| `Instrument/default/LookThroughPortfolioScope` | NO | String |  |

## Legal entity system properties

Note you can only use legal entity system properties with [legal entities](/v1/docs/representing-institutions-in-lusid-using-legal-entities) (not other types of entity).

| **System property key** | **Writable?** | **Data type** | **Explanation** |
| --- | --- | --- | --- |
| `LegalEntity/default/LEI` | YES | String | Stores the Legal Entity Identifier, a 20-character alpha-numeric code based on the ISO 17442 standard. See [gleif.org](https://www.gleif.org/en) for further information. |