This line chart displays the historical value of your portfolio, over a given period, converted into a specific currency. This includes all currencies, not just your reporting currencies. The target currency must be one of your reporting currencies.
The resolution of this chart is daily.
If you are looking for a breakdown of the value of each currency in your portfolio, consider the Converted Portfolio History chart.
For each account, address and offset in your portfolio, the balances, history and transactions are summed up for each currency, and converted with the closing (composite) rate for each day.