---
title: "CSI 300: Methodology"
description: "CSI 300 is maintained by China Securities Index and covers large/mid-cap shanghai + shenzhen a-shares. How the index selects and weights its constituents, and what that means for what it measures."
canonical: https://www.getswoopr.com/stocks/indexes/csi-300/
source: "Swoopr Investment: https://www.getswoopr.com"
---

# CSI 300: What It Measures and How It Is Built







## Direct Answer



> The CSI 300 is a rule-based measurement of large/mid-cap shanghai + shenzhen a-shares, maintained by China Securities Index. 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 CSI 300 covers large/mid-cap shanghai + shenzhen a-shares, within the China market. China Securities Index 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 300 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 China Securities Index's current methodology document, so none is stated here rather than guessed. The provider link below is authoritative.








## Current CSI 300 constituents



China Securities Index publishes and licenses the CSI 300 constituent list. Swoopr does not republish it here. The provider's own page is the authoritative source for current membership and weights.



[China Securities Index: official CSI 300 page](https://www.csindex.com.cn/en-us)








## 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 CSI 300?



China Securities Index maintains the CSI 300 and publishes the methodology document that defines its eligibility and weighting rules.




### What does the CSI 300 measure?



It measures large/mid-cap shanghai + shenzhen a-shares. 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 CSI 300 constituents?



China Securities Index 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.