A holding can be one of the following types:
A holding in an instrument.
The settled cash balance. For example, the cash from a SELL trade which settled last week is included in this balance.
Future cash payment in/out of the portfolio from trading activity. For example, the unsettled cash from yesterday's BUY trade. Each separate unsettled trade is represented as a unique line in the response.
Future cash flow into the portfolio from non-trading activity such subscriptions, redemptions, fees, taxes etc. This label of "Receivable" is used to capture the class of holding types which represent both Receivables and Payables.
Future cash flow that has been classified as an accrual (e.g. accrued dividend from a corporate action)
Future cash flow from an FX forward transaction. These will be represented in pairs, one for each leg of the FX Forward.