Alpha of Portfolio Calculator
Is Active Management Actually Adding Value?
Alpha measures the return a holding produces above and beyond what its risk level would predict — it's the number fund managers point to as evidence of skill rather than luck. A portfolio built from several positions, each with its own alpha, needs those figures combined the same way returns and betas do: weighted by how much capital sits in each one. This calculator produces that blended figure so you can judge the whole portfolio's excess performance at a glance.
The Formula
As with portfolio beta, weights are normalized to sum to 100% before being applied, so entering raw dollar amounts, share counts, or percentages all produce the same result.
Where This Matters
- Evaluating a fund manager — a consistently positive portfolio alpha across holdings is one of the few objective signs that active selection is beating a risk-adjusted benchmark.
- Blending active and passive positions — combining a market-tracking index fund (alpha near zero) with actively managed positions lets you see the net alpha contribution of the active sleeve.
- Attribution reviews — seeing each holding's weighted alpha contribution separately highlights which specific positions are driving (or dragging down) overall outperformance.
| Holding | Weight | Alpha | Weighted contribution |
|---|---|---|---|
| Holding 1 | 40% | 1.5% | 0.60% |
| Holding 2 | 30% | -0.5% | -0.15% |
| Holding 3 | 30% | 2.0% | 0.60% |
| Portfolio Alpha | 1.05% | ||
Even with one underperforming holding dragging on the total, the blend still nets a positive 1.05% alpha.
How to Use This Calculator
- Enter the weight of each holding, comma-separated (e.g.
40,30,30). - Enter each holding's alpha as a percentage, comma-separated, in the same order (e.g.
1.5,-0.5,2.0). - Select Calculate to see each holding's normalized weight and the combined portfolio alpha.
Related Calculations
Compare this against the Portfolio Beta Calculator for the risk side of the equation, or the CAPM Calculator to see what return beta alone would have predicted.