Every trade booked to an account alters a position in this contract.

Types of position accounting

Accounts used for strategies (Virtual Accounts or Strategy Subaccounts) may choose the type of position accounting:

Netted (default) — there may be only one position in a given contract on the account
Hedged — there may be different positions in one contract

When using the hedged mode, every order must specify the Position Effect — whether its execution opens a new position or closes an existing one. The field named StrategyPositionId links orders, trades, and positions.

Broker accounts always use the Netted accounting.

Executable subaccounts (ESAs) have the same accounting as the strategy they are subscribed to.

Position

Property	Description
OpenTradeId	ID of the last trade that affected the position. See explanation about position history below.
AccountId
StrategyPositionId	For accounts that use Hedged accounting, an arbitrary string identifying the position.
ContractId
Volume	Unsigned volume in contract units
SignedVolume
Side
OpenPrice	TotalOpenPayments / Volume
TotalOpenPayments	Sum of the payments of all trades that increased the position
OpenDt	Initial open timestamp
HistoryOpenDt	Timestamp of the last change (due to the trade or end of day)
TotalSettlPayments	Value of the position at the last end of day in the settlement/quote currency
TotalSettlPaymentsInAccountCcy
SettlPrice	TotalSettlPayments / Volume
CloseTradeId	Only for positions history — reference to the trade that changed the position
ClosePrice	Only for positions history. See explanation about position history below
CloseDt	Only for positions history
IsClosed
RealizedPnL	Gross PnL (not accounting for commissions) attributed to this position history record
RealizedPnLInAccountCcy
FloatingPnL	Daily floating PnL attributed to this position history record
TotalFloatingPnL
Commission	Total commission attributed to this part of the position.
For opened positions it equals the sum of commissions of opening trades, for closed positions — commissions of opening trades and the closing trade.
SignalGroupId
IsSynthetic	Whether the contract is synthetic
ParentPositionId	For positions that are real positions in legs of a synthetic contract, contains the reference to the parent position in the synthetic contract
ChangeType	Only for position history records — the type of the change:
• Open
• Close
• MTM (mark to market at the end of day)

Position history

Whenever a position changes, a history record is saved to indicate the position's state at that time. For example:

The first trade opens a position +10 AAPL @ 295
The second trade +5 AAPL is booked:
- The open positions will contain one position +15 AAPL. Its OpenTradeId will be set to the ID of the second trade, and HistoryOpenDt — to its timestamp
- Position history will contain a record +10 AAPL, with CloseDt and CloseTradeId set to those of the second trade; and OpenDt and OpenTradeId — to those of the first one. The close price will be equal to the open price (since the position has increased and there was no change in realized PnL)
If the position is partially closed, the volume of the position history record will reflect the closed amount. The record will additionally contain the realized PnL attributed to the closed part. The commissions and TotalFloatingPnL are distributed between the closed and the remaining part proportionally to their volumes.
At the end of day all positions are marked to market. Position history records are created for all existing positions, with CloseDt equal to the timestamp of the end of day, ClosePrice — to the end of day price, and FloatingPnL reflecting the today’s value. For the active positions, SettlPx will be updated to the end of day price, HistoryOpenDt — to the timestamp, and TotalSettlPayments — to the value as of the end of day.

Position history allows us to see the actual positions at any moment in time (by selecting history records with HistoryOpenDt ≤ timestamp and CloseDt ≥ timestamp) and helps build P&L reports.

PnL and yield calculation

At the end of each day (the exact time is determined by platform-wide settings), all active positions and balances are marked to market. For contracts quoted or settled in currencies different from the account base currency, the value is converted to the account currency. The account's total equity is recorded and compared with the equity at the end of the previous day to calculate the daily PnL.

Yield also accounts for the changes in the investment; see details here.