Final answer:
To calculate the standard deviation of a portfolio, we need to take into account the weights and correlations of the individual stocks. In this case, Stock A has a weight of -0.29 and Stock B has a weight of 0.71.
Step-by-step explanation:
To calculate the standard deviation of a portfolio, we need to take into account the weights and correlations of the individual stocks. In this case, Stock A weighs -7 million / (-7 million + 17 million) = -0.29, and Stock B weighs 17 million / (-7 million + 17 million) = 0.71.
The standard deviation of the portfolio can be calculated using the formula:
Standard Deviation = sqrt((weight A)^2 * (SD A)^2 + (weight B)^2 * (SD B)^2 + 2 * weight A * weight B * (correlation * SD A * SD B))
Plugging in the values, we get:
Standard Deviation = sqrt((-0.29)^2 * (0.4)^2 + (0.71)^2 * (0.45)^2 + 2 * -0.29 * 0.71 * (0.45 * 0.4)) = 0.386, or 38.6%