Current price per coin &  market value of current holdings for a coin:

These two values are determined by the source of the price selected. Here's how you can change the source: https://support.getdelta.io/getting-started/advanced/how-do-i-choose-the-source-of-the-price-for-a-certain-coin

Let's take an example here of Ethereum (ETH). I have selected GDAX as the exchange and ETH/BTC as the pair. BTC is the base pair here. The price per coin i.e. ETH/BTC is taken directly from the exchange and displayed if in BTC view mode or is converted using the exchange's BTC/USD or BTC/USDT rate to display the price per coin in USD.
If an exchange doesn't have its own BTC/USD(T) pair, we use the BTC/USD from coinmarketcap.com for the conversion.

The market value of current holdings is then, simply, amount of the coin x current price.

All-time profit / loss for the whole portfolio:

All time profit/loss (in absolute) = Sum of total market value of all coins - Sum of all coins actual cost

Sum of all coins actual cost = sum of costs (from all purchases) - sum of proceeds (from all sells) + Total Deposited - Total Withdrawn

and

All time profit/loss (in percentage) = (All time profit/loss in absolute x 100) / Sum of all coins actual cost

Sum of all coins actual cost = sum of costs (from all purchases) - sum of proceeds (from all sells) + Total Deposited - Total Withdrawn

All-time profit / loss for a single coin:

All time profit/loss (in absolute) = Total market value + Proceeds - Sum of all costs (from all purchases)

and

All time profit/loss (in percentage) = (All time profit/loss in absolute x 100) / Sum of all costs (from purchases)

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