On iOS

Your Portfolio Dashboard is divided into two sections. The top section provides an overview of your account and includes the following statistics:

Net liquidation value reflects your current account value – if you were to close (i.e., liquidate) every position in your portfolio at the current market price, thus converting every holding into cash, this is the amount you’d have.
Buying power is the maximum amount you can currently spend on buying stocks. For example, if your buying power is $5000, then you can purchase up to $5000 worth of stocks.
Cash is your current cash balance. Cash balance can be negative if you are employing leverage in your account. More on this shortly.
P&L today is your profits and losses on the day.
Leverage is defined as the ratio of your total stock values and your account value. If you start with $100 of cash and purchase $150 worth of stocks, then your cash balance becomes $ -\$50 $. Your account value is still $-50 + 150 = 100$ and your leverage is $ 150 / 100 = 1.5 $.

For a more comprehensive discussion of these statistics and margin trading in general, refer to Understanding Stock Margin Account.

The bottom section of the screen includes all your open positions. For each position, the following statistics are reported:

Shares: The number of shares you are currently holding. Short positions are reported with negative numbers.
Entry: The average entry cost of your position.
Last: The latest market price of your position.
Value: The market value of your position, calculated as $\text{share number} \times \text{last price} $.
Unrealized P&L: Unrealized profits and losses on this position. Unrealized P&Ls become “realized” once you close the position.

On the Web

Your Portfolio Dashboard contains two tables. The first table provides an overview of your account and includes the following statistics:

Net liquidation value reflects your current account value – if you were to close (i.e., liquidate) every position in your portfolio at the current market price, thus converting every holding into cash, this is the amount you’d have.
Cash is your current cash balance. Cash balance can be negative if you are employing leverage in your account. More on this shortly.
Buying power is the maximum amount you can currently spend on buying stocks. For example, if your buying power is $5000, then you can purchase up to $5000 worth of stocks.
Leverage is defined as the ratio of your total stock values and your account value. If you start with $100 of cash and purchase $150 worth of stocks, then your cash balance becomes $ -\$50 $. Your account value is still $-50 + 150 = 100$ and your leverage is $ 150 / 100 = 1.5 $.
P&L today is your profits and losses on the day.

For a more comprehensive discussion of these statistics and margin trading in general, refer to Understanding Stock Margin Account.

The bottom table of the page includes all your current positions. For each position, the following statistics are reported:

1D P&L: Today’s profits and losses of a position.
Position: The number of shares you are currently holding. Short positions are reported with negative numbers.
Average Cost: The average entry cost of your position.
Last Price: The latest market price of your position.
1D Chg (%): The latest 1-day percentage change in the stock’s price.
Market Value: The market value of your position, calculated as $\text{share number} \times \text{last price} $.
Realized and Unrealized P&L: The realized and unrealized profits and losses on this position. If you originally purchased 100 shares of stock A and then sold 20 shares. The profits and losses on these 20 shares are called the “realized P&L,” while the profits and losses on the remaining 80 shares are the “unrealized P&L.”