Profit and loss

The result, in money, of what has been dealt. On a single position it is the difference between the closing and opening prices multiplied by the units the position covers, expressed first in the currency the instrument is quoted in and then converted into the account currency. It exists in two states. While the position is open the figure is unrealised and changes with every tick. When the position closes it becomes realised and is written to the balance, which is why balance and equity differ by exactly the unrealised total.

What belongs in the figure is wider than the price difference. Commission is charged on the deal, financing accrues each night a position is held, and dividend adjustments apply on share and index contracts. A platform's profit column typically reports the price difference alone and keeps commission and swap in columns of their own, so the result of a position is the sum of the three rather than the number under the heading that says profit. An account level figure adds one more layer, since deposits and withdrawals move the balance without being a result of anything traded.

Two details cause most of the confusion. A position is valued at the price at which it could be closed, which is the opposite side of the quote from the one it was opened on, so it shows a small negative the moment it opens: that is the spread already accounted for, not a loss that has separately occurred. And the unrealised figure is not merely informational. It moves equity, and equity is what the margin level is calculated from, so an unrealised loss has consequences for an account long before anything is realised.