An index is a scoreboard for a group of securities chosen by fixed rules. Some indexes weight companies by market value; others use equal weights or other methods. Fund managers and news headlines use indexes as benchmarks: did this portfolio beat or lag the market? You cannot invest in an index itself, but index funds and exchange traded products try to copy its returns. Knowing what sits inside an index stops you from treating every market move as a personal portfolio move.
Key takeaways
- An index summarises many prices into one comparable number.
- Methodology (who is included and how they are weighted) changes the story.
- Indexes are benchmarks, not guarantees of your own results.
- Index tracking products aim to match, not beat, the chosen basket.