Hi All,
To understand a lot of the complex ideas in CFA, I usually create my own example of “pseudo real life” and try and apply what I have learned.
I am having a problem that I can’t seem to figure out.
Here is the example set up:
A 2 asset portfolio setup.
I have 20 year returns of Small Caps and Bonds. I want to see what the Standard Deviation of the portfolio would be if I invest 60% in Small Caps and 40% in Bonds.
Small Caps mean return = 11.12% with a standard deviation of 18.79%. Bonds mean return = 5.35% with a standard dev of 3.53%.
This is the Covariance matrix I get :
Small Cap Variance: 0.035304 Bond Variance: 0.001249 CoVariance: 0.000342 (Calculated this way: 0.60*(11.12-6.67)+0.40*(5.35-2.14))
I am getting an expected return of 8.81% and a st. dev of portfolio to be 11.43%. Is that right?
Also, for correlation, when I have Excel calculate it based on 20 year history and using “correl” command, it is giving me -0.37. Doing it via formula manually from above covariance, I am getting a correlation of 0.05. Big difference there. I can understand some difference due to the weights vs. using Excel command on 20 year data…but that much?
Appreciate someone’s help. THis is good example for practice. If I have left out some key data, let me know.