Deleted
You’d do it the same way you would with any portfolio:
r_port_ = Σw_i_r_i_
where w_i_ = beginning value of stock i divided by the beginning value of the subportfolio.
For example, suppose that you have a portfolio with these returns and beginning values:
- Stock A: $10,000, r = 4%
- Stock A: $20,000, r = 5%
- Stock A: $30,000, r = 2%
- Stock A: $40,000, r = −1%
If you want the return for the subportfolio comprising stocks A & C, then the weight on A is ¼ and the weight on C is ¾: $10,000 / ($10,000 + $30,000) and $30,000 / ($10,000 + $30,000), respectively.
The return is ¼(4%) + ¾(2%) = 2.5%.
http://www.aaii.com/journal/article/how-to-calculate-the-return-on-your-portfolio
#WeightedAverageReturn
In excel, it would be sumproduct (returns, dollar balance) / sum(dollar balance)