The total original buy value of positions, excluding fees and taxes. Positions whose buy price
could not be determined are not part of this sum.
The day that has actually been valued, YYYY-MM-DD. This equals requestedDateString, except for
weekend requests which are answered with the preceding friday (the history only holds weekdays).
Positions that have been booked out because they knocked out or expired (they vanish from the portfolio without a sell order).
This is not filtered to dateString: an instrument that knocked out earlier explains why it is
absent from positions.
The open positions at the end of dateString. Empty if nothing was held on that day.
The date as it has been requested, so that a client can match up its request.
The total end-of-day value of positions (positions only, no cash).
The open positions of a portfolio at the end of one single day, with the price inputs each of them has been valued with. This is the detail behind one point of the value history.