---
title: "Nikkei 225: Methodology"
description: "Nikkei 225 is maintained by Nikkei and covers price-weighted japanese blue-chip benchmark. How the index selects and weights its constituents, and what that means for what it measures."
canonical: https://www.getswoopr.com/stocks/indexes/nikkei-225/
source: "Swoopr Investment: https://www.getswoopr.com"
---

# Nikkei 225: What It Measures and How It Is Built







## Direct Answer



> The Nikkei 225 is a rule-based measurement of price-weighted japanese blue-chip benchmark, maintained by Nikkei. Like every index it owns nothing: it is a number produced by applying a published weighting formula to a selected list of companies, revised on a schedule the provider sets.








## What this index covers



The Nikkei 225 covers price-weighted japanese blue-chip benchmark, within the Japan market. Nikkei defines which securities are eligible, how they are selected from that pool, and how much each one contributes to the published number.



The name states a target of 225 companies. A target is not a guarantee of the exact count on any given day: corporate actions, dual share classes and pending additions all move the real number around it.








## How constituents are weighted



Swoopr has not verified the weighting method for this index against Nikkei's current methodology document, so none is stated here rather than guessed. The provider link below is authoritative.








## Current Nikkei 225 constituents



Nikkei publishes and licenses the Nikkei 225 constituent list. Swoopr does not republish it here. The provider's own page is the authoritative source for current membership and weights.



[Nikkei: official Nikkei 225 page](https://indexes.nikkei.co.jp/en/nkave)








## Related reading



- [All stock market indexes](https://www.getswoopr.com/stocks/indexes/): how indexes are built, weighted and revised.
- [Asia-Pacific indexes](https://www.getswoopr.com/stocks/indexes/asia-pacific/): others covering the same region.
- [Index concentration](https://www.getswoopr.com/technical-analysis/market-concentration/index-concentration/): measuring how much of an index sits in its largest holdings.
- [Index rebalancing and inclusion effects](https://www.getswoopr.com/stocks/corporate-actions-catalysts/index-rebalancing-and-inclusion-effects/): what happens to a stock when index membership changes.








## Frequently Asked Questions


### Who maintains the Nikkei 225?



Nikkei maintains the Nikkei 225 and publishes the methodology document that defines its eligibility and weighting rules.




### What does the Nikkei 225 measure?



It measures price-weighted japanese blue-chip benchmark. The index is a calculated number applying a weighting formula to a selected list of companies, and it holds nothing itself.




### Where can I see the current Nikkei 225 constituents?



Nikkei publishes the current constituent list. Swoopr does not republish it, because index providers license constituent data and Swoopr holds no such licence.











## About the author



The [Swoopr Editorial Team](https://www.getswoopr.com/authors/swoopr-editorial-team/) writes Swoopr Investment's educational library, covering market structure, analysis methods and the mechanics behind the numbers investors read every day.



Our [editorial policy](https://www.getswoopr.com/legal/editorial-policy/) and [corrections policy](https://www.getswoopr.com/legal/corrections-policy/) set out how this content is produced, reviewed and fixed when it is wrong.