The percent gain or loss of the invested monies into an investment:

The end value already includes reinvested distributions, so end value + distributed distributions + redemptions gives the value generated by any purchases. Purchases includes any purchases made during the period plus the starting value for the date range.  This field is labeled %Gain-I.

Note on Short Positions:

For short positions "purchases" are selling short, or increasing your short position, and "redemptions" are buying shares (covering/decreasing your short position).  The absolute value of purchases is used in the denominator to provide meaningful figures.