Fixed Fractional with Margin - Money Management Strategy
The Fixed Fractional with Margin strategy selects the number of contracts or shares to place on a trade based on several parameters. The parameters that are used to determine the number of contracts or shares to trade include the portfolio equity, the margin required per unit traded, the amount of portfolio equity to be risked, maximum number of contracts or shares and the allowable multiple of margin that can be purchased.
The percent risk is the percent of the total portfolio equity expressed in the selected currency that is available to invest in a trade. The number of contracts or shares N to place on a trade is calculated as:
N = Integer (Total Equity*Percent Risk/Margin). If N <= Maximum Number of Contracts/Shares then N is the final number.
Example
Total Equity = $100,000, Percent Risk = 10% and Margin =$4,000. Then N= Integer (100,000*0.1/4000) = 2. If Maximum Number of Contracts is 10 then since 2 < 10 then N = 2.
Since many securities can be traded with leverage (that is buying more of a security than one has capital for) it is also possible to allow the number of contracts or shares purchased to be a multiple of the margin required for each position. The field Multiple of Margin establishes that multiple. For example, a share of SPY at 110 normally requires $110 (assuming leverage of one) to buy one share. However, if the multiple of margin is set to two then one share could be purchased for every $55 available in capital.
Example
If we are trading the SPY shares on the Amex each point is worth $1 and the SPY is trading at 110. Let's say we select 10 percent to risk on every trade and the current portfolio equity is 50,000. We therefore have 5,000 available for this trade. As in the case with stocks the margin will be $110 per share. However, we are trading with a multiple of 2 or two times leverage for each position (relative to the capital allocated for a trade). We can therefore buy 5,000/$55 or 90 shares of the SPY on this trade using the Fixed Fractional with Margin strategy. Since 90 is smaller than the Maximum Number of Contracts set to 500, then 90 shares will be used as this trade size.