The money in a trading account counting only what has been settled: deposits and withdrawals, and the results of positions that have been closed.
It does not move while a position is open; the profit or loss on an open position shows in equity and reaches the balance only when the position is closed.
balance = deposits − withdrawals + results of closed positions
Worked example
A balance of 10,000 with one open position that is 150 in loss is still a balance of 10,000; the equity is 9,850.
Educational information, not investment advice or a recommendation to trade.