pgarland1 / stock-portfolio-manager

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Cost basis incorrect #73

Open GoogleCodeExporter opened 8 years ago

GoogleCodeExporter commented 8 years ago
What steps will reproduce the problem?
1. Look at the cost basis in the Performance panel field on the picture located 
at https://code.google.com/p/stock-portfolio-manager/
2. Let's use the RY.TO stock for discussion
3.

What is the expected output? What do you see instead?
The transaction cost of RY.TO is $1434.90. Since there are 30 shares owned the 
correct adjusted cost basis per share should be $47.83. The average cost per 
share of $47.50 is correct but it is useless from an investment point of view 
as it is not including the commission cost for the two purchase transactions. 
If you execute a sell trade using the 47.50 as your adjusted cost you may end 
up in a situation where it looks like you made money but actually lost money, 
net of commissions. 

What version of the product are you using? On what operating system?

Please provide any additional information below.
Recommend you put in a foreign exchange field, on a per transaction level. Many 
people make the mistake of doing this on a global basis but if you know 
anything about stock trades you'll know that foreign exchange always changes so 
each transaction exchange rate is different. You'll want the FX to be able to 
do at least 4 decimal places. 

Let's do an example:

BUY 100 IBM (NYSE) @ $163.138 $USD 
Commission is $6.95 $USD
FX to CAD is 1.12400
Adjusted Cost Basis = ((100 x $163.138) + $6.95) x 1.12400 = $18344.523

SELL 100 IBM (NYSE) @ $164.250 $USD
Commission is $6.95 $USD
FX to CAD is 1.11760
Cost of Liquidating = ((100 x $164.25) + 6.95) x 1.11760 = $18348.813

Net gain = $4.290 
(I made $1.1120 per share but lost almost all of it because of FX.)

Original issue reported on code.google.com by jkn...@gmail.com on 10 May 2015 at 2:49