# Jensen's Alpha: Explained

## What is it, how to calculate it, formula, why it's important

Have you ever heard of Jensen's Alpha? No, it's not some kind of superhero. It's actually a term used in finance to measure the performance of an investment. And let me tell you, it's pretty important.

So, what exactly is Jensen's Alpha? In simple terms, it's a measure of a portfolio's risk-adjusted performance. In other words, it tells you whether an investment is doing better or worse than it should be, based on the amount of risk it is taking on.

But where did this term come from? It's named after Michael Jensen, a finance professor at Harvard Business School who came up with the concept in the 1960s. And it's been widely used ever since.

But enough history, let's get into the nitty-gritty of how Jensen's Alpha works.

## The Formula

Without going too much into the technical details, the formula for Jensen's Alpha is pretty straightforward:

(Actual Return) - (Expected Return)

Where the expected return is calculated using the CAPM (Capital Asset Pricing Model), which takes into account the risk-free rate, the market risk premium, and the stock's beta.

Now, don't worry if that sounds like a foreign language to you. All you need to know is that Jensen's Alpha compares the actual return of an investment to what we would expect it to have returned based on the level of risk it is taking on.

## Interpreting Jensen's Alpha

So, let's say we have two investments with the same level of risk. Investment A has an actual return of 10%, while Investment B has an actual return of 12%. But when we calculate their expected returns using the CAPM, we find that Investment A should have returned 8%, while Investment B should have returned 9%.

Using the formula we mentioned earlier, we can calculate the Jensen's Alpha for each investment:

Investment A: 10% - 8% = 2%
Investment B: 12% - 9% = 3%

As you can see, Investment B has a higher Jensen's Alpha than Investment A. That means it has done a better job of delivering returns relative to the risk it is taking on.

Now, it's worth noting that Jensen's Alpha is not a perfect measure of performance. It has its limitations and should be used in conjunction with other performance metrics. But it is a useful tool to have in your investment arsenal.

## The Bottom Line

Jensen's Alpha may not be the most exciting topic in the world of finance, but it's an important one. As investors, we want to make sure we're getting the best return possible for the amount of risk we're taking on. And Jensen's Alpha helps us do just that.