--- title: "MSX 30 Index: Methodology" description: "MSX 30 Index is maintained by Muscat Stock Exchange and covers top 30 companies listed on the Muscat Stock Exchange by market capitalisation." canonical: https://www.getswoopr.com/stocks/indexes/msx-30/ source: "Swoopr Investment: https://www.getswoopr.com" --- # MSX 30 Index: What It Measures and How It Is Built ## Direct Answer > The MSX 30 Index is a rule-based measurement of top 30 companies listed on the Muscat Stock Exchange by market capitalisation, maintained by Muscat Stock Exchange. 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 MSX 30 Index covers top 30 companies listed on the Muscat Stock Exchange by market capitalisation, within the Oman market. Muscat Stock Exchange 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 30 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 Free float market capitalisation weighted, with a 10% cap per company applied through a capping factor. Founders, government holdings, strategic holdings of 10% or more and shares locked in for at least three months are excluded from free float. Free float and capping factors are reset quarterly. The weighting method is the single biggest driver of how an index behaves. Two indexes covering the same market can diverge for years purely because they weight differently, which is why comparing index levels without knowing the method tells you very little. ## What qualifies for inclusion Common shares of public joint stock companies on the Regular and Parallel markets; preferred shares, bonds, funds and Third Market companies are excluded. Selection scores market capitalisation at 40%, liquidity at 45% and return on investment at 15%. Eligibility rules are the part of an index most readers never look at and the part that decides what it can possibly measure. A screen that excludes a whole sector, or admits only one listing venue, shapes the result far more than any day of trading does. ## How long a listing must exist first Newly listed companies are considered for inclusion only after a minimum of six months from the listing date. A seasoning rule is why a large new listing does not appear in an index the week it starts trading. It is a deliberate lag, and it means an index can under-represent a fast-growing part of the market for months at a time. ## When the membership is revised The sample is reviewed and reconstituted annually, and companies are added or removed only at that review. The guide places the sample amendment at the beginning of July, while free float and capping factors are reset at the end of March, June, September and December. Reconstitution is the one date an index changes shape by design rather than by price. Funds tracking it have to trade toward the new membership, which is why the schedule matters to anyone holding the tracker rather than only to the provider. ## The rule that surprises people MSX keeps the right to include or exclude any company to meet the index objectives, so the scored selection is not purely mechanical. ## References - [Muscat Stock Exchange: Muscat Stock Exchange MSX30 Index Guide April 2021](https://www.msx.om/MSMDOCS/downloads/en_1619947612937_MSX30%20EN.pdf), as published 2021. Every rule described on this page is taken from this document. ## Current MSX 30 Index constituents Muscat Stock Exchange publishes and licenses the MSX 30 Index constituent list. Swoopr does not republish it here. The provider's own page is the authoritative source for current membership and weights. [Muscat Stock Exchange: official MSX 30 Index page](https://www.amf.org.ae/en/amf_indices/yearly) ## Related reading - [All stock market indexes](https://www.getswoopr.com/stocks/indexes/): how indexes are built, weighted and revised. - [Emerging Markets indexes](https://www.getswoopr.com/stocks/indexes/emerging-markets/): 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 MSX 30 Index? Muscat Stock Exchange maintains the MSX 30 Index and publishes the methodology document that defines its eligibility and weighting rules. ### What does the MSX 30 Index measure? It measures top 30 companies listed on the Muscat Stock Exchange by market capitalisation. 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 MSX 30 Index constituents? Muscat Stock Exchange 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.