A transaction portfolio in LUSID records a transaction history of economic events such as transactions and corporate actions. This events store enables LUSID to calculate holdings (at the taxlot level if required) and cash balances. The calculated holdings (positions) form part of the input into the calculation of valuations and trading position profit and loss within LUSID.

User defined ‘properties’ can be associated with portfolios to add in additional model data (e.g. a property for ‘portfolio manager’ could be added and linked to a portfolio for management and reporting purposes).

To support reconciliation between different views of the same portfolio (e.g. front office portfolio management system against the fund accounting view) a transaction portfolio can have holdings loaded directly, causing LUSID to automatically determine the 'correcting trades' which are required to bring the holdings in line with what has been specified. The 'correcting trades' can be used to identify e.g. late or incorrectly booked transactions.