Definition: The maximum current cost at any time point.
Explanation: This prevents double counting if user reinvests the money
However, if there is a huge capital outflow (and not coming back), then "P&L + Dividends + Closed" percentage will be depressed.
Example: If I started with $100,000 worth of stocks but because I needed cash (for whatever reasons),
I closed many positions and diverted the money elsewhere leaving only $10,000 worth of stocks for the next 5 years,
then it might not be reasonable to compute the returns based on $100,000 (max deployed capital).