Find the stocks that really move your ETF
ETF Scanner searches 6,000+ Korean and US ETFs, and dissects the 4,000+ whose holdings we have at the constituent level, so you can see exactly which holdings lifted — or dragged down — your ETF today.
The question this site answers
Most investors know what their ETF holds, but not who actually drove its move today. If the index rose +1% and a single stock produced half of that, you're not really index-investing — you're concentrated in that one name. ETF Scanner answers these questions with numbers:
- Which stock lifted my ETF the most (the hero) and which dragged it down (the suspect)?
- How would the return change if one stock were removed? (What-If simulation)
- Are my several ETFs secretly overlapping on the same stocks?
- How concentrated is this ETF in a few names? (HHI)
Tools we provide
How the numbers are computed
Every metric is a plain calculation from public definitions — no arbitrary weighting or hidden algorithm.
- Contribution (%p) = (weight ÷ 100) × stock return. A 10% holding falling 2% contributes −0.20 percentage point. Cash, derivatives, currency and timing can cause the stock contribution sum to differ from the ETF's market return. Read the Others, estimate and tracking-difference labels alongside it.
- What-If return: excluding a holding simply drops its contribution and leaves the rest untouched. Remaining weights are not renormalized, so the change in return equals exactly the contribution shown for that holding.
- Concentration (HHI): sum of squared weights, quantifying top-holding skew.
- Full definitions are in the Glossary and ETF Anatomy.
Limitations & disclaimer
Figures refer to the stated time. This service is for reference only and is not investment advice. Investment decisions and outcomes are your responsibility.
Contact
For data corrections, partnerships, or any inquiry, email kospi9988@gmail.com or use the contact page.