Adding an Asset to a Portfolio – Improving the Minimum Variance Frontier
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We can use the Sharpe Ratio to determine if adding an asset creates a better (higher) minimum variance frontier.
The Sharpe ratio is calculated using the following formula:
Sharpe Ratio = (E(Rasset) – RF)/σasset
Calculate the Sharpe ratio for the current portfolio and then calculate the Sharpe ratio after adding the new asset.
If the Sharpe Rationew port > (Sharpe Ratiocurrent port * ρ(new asset, current port)), then the new asset should be added.
ρ(new asset, current port) = correlation coefficient between the current portfolio’s returns and the new asset’s returns