Suppose you have three stocks in your portfolio. Suppose you have ten shares of Stock A which is currently trading at $15 per share;
you have 20 shares of Stock B which is currently trading at $19 per share; and 30 shares of Stock C which is currently trading at $22 per share. What is the weight of each stock in your portfolio?
Suppose the next day you find that Stock A had a return of positive 5 percent, Stock B had a return of negative 2 percent, and Stock C had a return of positive 9 percent.
What is the portfolio's return? What are the new weights in your portfolio?