Optimizing Portfolio in Excel

I have a set of opening stock data for which i have calculated the returns and the mean returns. I need to now create a covariance matrix which i do not understand how to do?

Can someone please help me on how i would generate the covariance matrix for the portfolio. I have attached my excel file containing the portfolio if any1 wants to see.portfolio.xls

Hi NFS,

Never done one before, but a simple Google search got me this...

http://www.allquests.com/question/40...ay-in-vba.html

Hope this helps...