The covariance between two investments of a portfolio is equal to the sum of the variances of the investments.

Covariance

A measure indicating the degree to which two random variables change together.

Variances

Statistical measures of the dispersion of data points in a dataset, indicating how far each data point in the set is from the mean.

Portfolio

A portfolio of investment vehicles, including equities, fixed income, raw materials, money, and money-like assets, along with mutual funds and ETFs.