Suggestion about portfolio calculations

New Member Joined: Feb 09, 2004 Posts: 7

As promised, here is my post about portfolio calculations. I have some suggestions.

I think the calculation of (+/-), the variable $glPercent, is not the best approach for the real percentage of gain/loss, and I would prefer to redefine the Current Value too ($curValue).

In fact you buy 50 shares today for $120 each. The total value of the shares you have is 50X$120=$6000. If you pay $200 of fees, The total cost for you is $6200. If the share value rises to $150, your portfolio value would be 50X$150=$7500. The gain/loss must be calculated by market value of your shares - total purchase cost(incl. fees) = $7500-$6200=$1300. This represents a gain of 1300/6200=20.96%

According to your variable definition, the variable $glPercent is actually calculating the gain/loss as a percentage of the current value, and I also think that there is no need for a vaiable like $curValue. The current value is being calculated by market value of shares - fees. I think it is better to have a variable calculating purchase price + fees, instead of that.

What I propose is renaming the variable $curValue to, for example, $totalCost. Define $totalCost=$origCost+fees_ Change the variable $gainLoss=$curPrice-$totalCost and $glPercent=($curPrice-$totalCost)/$totalCost.

I would like to know the opinions of someone else about this. I have changed my index.php file. If someone wants to see, just let me know.

Site Admin/Owner Joined: Aug 27, 2002 Posts: 17088

This was debated when it was first written. I had at least 2 stock savvy people directing me on this. That's one of the reasons that there are 2 different configurable ways for calculation open/close prices. I will leave the disucssion open to see what others think. OTOH, this is the joy of OpenSource - you can customize it for your purposes!

Posted: Tue Feb 10, 2004 11:35 am

Ok. I prefer to do this in the way I posted here. If anyone is interested and prefer to have the script configured in the way I said, I will be more than happy to help, providing my configuration.