What correlation would an investor need in order to eliminate the variability in the total...

Correlation measures how two securities move in relation to each other. A correlation of +1.0 means the two stocks move perfectly together, so diversification provides no reduction in variability. A correlation of 0.0 means there is no consistent relationship, which reduces some portfolio risk but does not eliminate variability. A correlation of +0.5 still shows a positive relationship, so risk reduction is limited. A correlation of -1.0 means the two securities move perfectly opposite to each other. In theory, if two assets have perfectly negative correlation and are properly weighted, one asset’s gain can offset the other asset’s loss, eliminating variability in total returns. Therefore, -1.0 is the correct answer.