When you configure a transaction type in LUSID you will need to specify a Side for each movement. Put simply, the Side tells LUSID which attributes (required, optional and/or properties) to use when converting a Transaction into a set of Movements that are used to generate the holdings for a portfolio.
1. Introduction
An example of a side is the default "Side1":
| Field | Value | Description |
| side | Side1 | The unique name for the side. In this example "Side1". |
| security | Txn:LusidInstrumentId | The security to use for the side. In this example this is the security that the Transaction resolves to as identified by its unique LUSID Instrument Id. |
| currency | Txn:TradeCurrency | The currency to use for the side. In this example this is the TransactionCurrency on a transaction. |
| rate | Txn:TradeToPortfolioRate | The exchange rate to the portfolio's base currency. This is used to maintain the cost basis in the portfolio's base currency. |
| units | Txn:Units | The units to use for the side. In this example this is the Units on a Transaction. |
| amount | Txn:TradeAmount | The amount to use for the side. In this example this is a calculated field which uses other attributes on the Transaction. |
Here you can see that each of the attributes are all prefixed with "Txn:" as they are either required, optional or calculated attributes on a Transaction.
The full list of predefined "Txn:" values for each Field in the side configuration is contained in the table below:
| Field | Valid side values | Description | Example value |
| security | Txn:LusidInstrumentId | The transaction's LUID. | LUID_98ABCDJK |
| security | Txn:SettlementCurrency | The transaction's settlement currency. | CCY_USD |
| currency | Txn:TradeCurrency | The transaction's currency. | GBP |
| currency | Txn:SettlementCurrency | The transaction's settlement currency. | USD |
| rate | Txn:TradeToPortfolioRate | The exchange rate between the transaction's trade currency and the portfolio base currency added to the transaction using the property Transaction/default/TradeToPortfolioRate | 1.09 |
| rate | Txn:SettledToPortfolioRate | The exchange rate between the transaction's settle currency and the portfolio base currency. | 1.78 |
| units | Txn:Units | The transaction's units. | |
| units | Txn:BondInterest | The accrued interest in the settlement currency that is included in the purchase/sale of a bond added to a transaction using the property Transaction/default/BondInterest | 12678 |
| units | Txn:TotalConsideration | The transaction's value in the settlement currency. | 102000 |
| units | Txn:BasedOnSeparateBondInterest | The transaction's total consideration with the bond interest subtracted. | 122000 |
| units | Txn:TradeAmount | The transaction's value in the transaction currency. | 8000 |
Sides are returned as part of the response to List transaction types.
2. Custom Sides
You can create custom sides via LUSID's SystemConfiguration API. This allows you to pick the values for the units, currency, security etc. from custom defined properties rather than the default transaction fields. You can find a great example of creating a side in the sample Jupyter notebook tracking your trading commissions. In the notebook the Side configuration is as follows:
| Field | Value | Description |
| side | TradeCommissions | The unique name for the side. In this example "TradeCommissions". |
| security | Txn:LusidInstrumentId | The security to use for the side. In this example this is the security that the Transaction resolves to as identified by its unique LUSID Instrument Id. |
| currency | Txn:SettlementCurrency | The currency to use for the side. In our example this is the Settlement Currency on a Transaction. |
| rate | Transaction/custodian/exchange_rate | The rate to use for the side. In this example this is the custom property Transaction/custodian/exchange_rate. |
| units | Transaction/custodian/broker_commission | The units to use for the side. In this example this is the custom property Transaction/custodian/broker_commission. |
| amount | Transaction/custodian/broker_commission | The amount to use for the side. In this example this is the custom property Transaction/custodian/broker_commission. |
In this instance you can see the use of custom properties defined by their three part propertykey instead of just the default transaction attributes.
3. Missing Values
Note that if you upsert a transaction with missing values for properties used by a custom Side the behaviour is as follows:
| Missing Field | Behaviour |
| security | The instrument will resolve to the LUSID unknown instrument with "LUID_ZZZZZZZ" |
| currency | The currency will resolve to the unknown currency "ZZZ" |
| rate | The rate will default to zero (0) |
| units | The units will default to zero (0) |
| amount | The amount will default to zero (0) |