Alpha (performance above the market)

What is Alpha

Alpha is an investment metric that measures how much an investment has outperformed or underperformed its benchmark after adjusting for risk. In other words, Alpha expresses so-called performance above the market. If a portfolio has an Alpha of +2%, it means the portfolio manager achieved a return 2 percentage points higher than the market they track. Conversely, an Alpha of -2% means the portfolio underperformed by 2 percentage points.

Alpha is one of the key metrics used to evaluate the skill of active managers, because it shows whether their decisions truly added value compared with passively copying the market.

How Alpha is calculated

The calculation of Alpha is based on the difference between the actual portfolio return and the expected return, estimated using models such as CAPM (Capital Asset Pricing Model). This model takes market risk into account, measured by Beta, and assumes the return the investment should generate if it exactly replicated the market.

A positive Alpha means the portfolio beat the market, a negative Alpha shows a worse result.

Why Alpha matters

Alpha is useful for investors who want to find out whether it makes sense to pay higher fees for active management. If a portfolio manager consistently produces a positive Alpha over the long term, it means their strategy delivers results beyond what passive investing offers. On the other hand, a long-term negative Alpha can be a signal that the investor should consider a different approach, such as passive investing.

Limits and risks of using Alpha

Though Alpha provides valuable information, it is not perfect. It measures only historical performance and does not guarantee that positive results will be repeated in the future. It can also be distorted by the choice of an inappropriate benchmark – if the manager picks an index that is easy to beat, Alpha can look artificially high.

Alpha should therefore be used alongside other metrics such as the Sharpe ratio, volatility or Beta, so that the investor gets a comprehensive view of risk and return.

A practical example

A fund tracks the performance of the S&P 500 index. Over the past year it delivered a return of 12%, while the market returned 9%. After adjusting for risk using the CAPM model, the fund's expected return comes out at 10%. This means the fund beat the market by 2 percentage points.

Alpha on the Stonkee platform

On Stonkee you can track Alpha in real time for selected super-investors, funds and individual portfolios. This lets users quickly see which managers or strategies consistently deliver performance above the market. The platform also allows you to compare Alpha with other metrics, so that investors can make decisions based on comprehensive data.

Summary

Alpha measures how much an investment has outperformed its benchmark after adjusting for risk. It helps investors assess whether active management really adds value. On Stonkee, Alpha is part of a broader analytical toolkit that helps users better understand the performance of their investments.