Mrtrader3. I take the value of my portfolio at the beginning of the tax year 1 March and then I take the value of my portfolio at the end of the tax year 28 February. Then I work out the percentage gain for the year and divide by 12 to get monthly average gain. But in between at each month end I calculate percentage gain to date. Strict money management is applied. Risk to total portfolio value is not allowed to be more than 2% at any given time. Note 2% risk not exposure. Risk is only applicable when entering a trade. Once profit starts running risk is eliminated. The total portfolio value can never incur a loss if properly managed.