On Beta (Part 3 of 3)
After presenting five different methods for calculating beta in Excel, I used examples to demonstrate why beta should not be used to set expectations about future return. There are several reasons for this:
- Beta isn’t even reliable for estimating the historical returns on which it is based.
- Beta is a point estimate summarizing a multitude of data points.
- A stock’s beta will change in the future.
- Using beta for stock projections, relies first on a prediction of the market’s return – a futile task.


