At a glance
- Provider
- MSCI; benchmark administrator MSCI Limited[3]
- Launched
- March 31, 1986[1]
- Coverage
- Large and mid cap in 23 Developed Markets countries, about 85% of free float-adjusted market cap in each[1]
- Constituents
- Not fixed: 1,280 as of August 31, 2026[1]
- Weighting
- Free float-adjusted market capitalization[2]
- Reviews
- Quarterly index reviews in February, May, August and November[2]
- Currency
- Standard factsheet quoted in USD[1]
Index levels and returns change every trading day and are not shown here. Check the provider's own page for current figures.
Quick answer
The MSCI World Index covers large and mid-sized companies in 23 developed-market countries, aiming for about 85% of each country's free float-adjusted market value. MSCI weights companies by that free float-adjusted value and reviews the index every quarter [1] [2].
Key points
- "World" means developed markets only: 23 countries, with emerging markets left out.
- Within each country, MSCI aims to capture about 85% of free float-adjusted market value using large and mid-sized companies.
- Weights follow free float-adjusted market value, so the biggest markets and companies dominate.
- The index is reviewed four times a year; which countries count as developed is reviewed every June.
- For a dollar-based investor, currency moves change the index's value even when local share prices do not move.
#What does the MSCI World Index cover?
MSCI's factsheet says the index "captures large and mid-cap representation across 23 Developed Markets (DM) countries" and "covers approximately 85% of the free float-adjusted market capitalization in each country" [1]. Large and mid cap means the bigger companies in each market; small companies are outside this index. Free float is the part of a company's shares that investors can actually buy.
| Region | Countries |
|---|---|
| Americas | Canada, United States |
| Europe and Middle East | Austria, Belgium, Denmark, Finland, France, Germany, Ireland, Israel, Italy, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom |
| Pacific | Australia, Hong Kong, Japan, New Zealand, Singapore |
The country list is the provider's, not ours; the regional grouping above is only for easier reading. Many large economies are missing because MSCI classifies them as emerging or frontier markets. For why spreading money across countries and companies matters, see diversification explained.
#How does MSCI decide which countries are developed?
MSCI uses a market classification framework with three criteria: economic development, size and liquidity requirements, and market accessibility [4]. Markets fall into four groups: developed, emerging, frontier and standalone [4]. Every June, MSCI announces the results of its Annual Market Accessibility Review, followed shortly by the Annual Market Classification Review [4]. A country's classification can therefore change, which would move it into or out of the developed-market group.
From a country to an MSCI World constituent
#How is the MSCI World weighted?
MSCI's Global Investable Market Indexes methodology uses free float-adjusted market capitalization weighting [2]. The key input is the Foreign Inclusion Factor, which MSCI defines as "the proportion of shares outstanding that is available for purchase in the public equity markets by international investors" [2]. The methodology sets a target coverage of 85% ± 5% for its Standard indexes, the large and mid-cap level used by the MSCI World [2]. For the basic size measure, see market capitalization.
Worked example
Worked example: free float and currency in a two-company index
Two hypothetical companies. J is listed in Japan: ¥2,000 share price, 1 billion shares, inclusion factor 0.70. U is listed in the U.S.: $80 share price, 500 million shares, inclusion factor 0.95. The index is calculated in U.S. dollars. First the yen trades at 150 per dollar, then at 160, with no change in either share price.
- J in dollars at ¥150 (2,000 × 1bn × 0.70 ÷ 150)
- $9.33 billion → 19.72% weight
- U in dollars (80 × 500m × 0.95)
- $38.00 billion → 80.28% weight
- J in dollars at ¥160
- $8.75 billion → 18.72% weight
- Change in J's dollar value from currency alone
- −6.25%
J's dollar value fell 6.25% and its weight shrank, although its share price in yen never moved. In a multi-country index, exchange rates are part of the result.
Hypothetical companies and exchange rates, calculated in Python.
#How often is the MSCI World reviewed?
MSCI holds index reviews in February, May, August and November [2]. Since February 2023, MSCI has applied its comprehensive review approach at each of those four quarterly reviews, instead of reserving it for May and November [5]. To limit unnecessary trading, the methodology uses buffer zones to manage companies migrating between size segments [2]. The number of constituents therefore changes over time: the August 31, 2026 factsheet listed 1,280 [1].
#How is MSCI World different from a U.S. index?
The S&P 500 covers large U.S. companies only. The MSCI World includes the U.S. plus 22 other developed markets, so it adds non-U.S. companies and exchange-rate effects. It still excludes emerging markets and small companies, so it is not literally the whole world. MSCI's own factsheets show it in more than one currency, such as a USD version with gross returns and a EUR version with price returns [6]. Funds that track it can differ from it because of fees and costs [7]; see index funds explained.
Common beginner mistakes
Reading "World" as "every country"
The index covers 23 developed markets. Emerging and frontier markets are outside it.
Assuming equal country weights
Weights follow free float-adjusted market value, so countries with very large stock markets carry far more weight than smaller ones.
Forgetting currency
An investor who measures results in a currency other than the one the index is quoted in sees an extra layer of gains or losses from exchange rates.
Using an old constituent count or country list
Membership changes every quarter and country classifications are reviewed every June. Check the date on any factsheet you rely on.
What's the bottom line?
The MSCI World is a free float-adjusted, cap-weighted index of large and mid-sized companies in 23 developed markets, reviewed quarterly and quoted in U.S. dollars on its standard factsheet. It is broad, but not global in the full sense, and currency is part of what it measures. For the basics of any index, start with what a stock market index is.
Frequently asked questions
Does the MSCI World include emerging markets?
No. It covers Developed Markets countries only. MSCI classifies other markets as emerging, frontier or standalone in separate indexes.
Does the MSCI World include small companies?
No. It captures large and mid-cap companies, aiming for about 85% of each country's free float-adjusted market value. Smaller companies fall outside that coverage.
Why do different websites show different MSCI World returns?
MSCI publishes the index in more than one currency and return type. Its standard USD factsheet shows gross returns, while its EUR factsheet shows price returns. Always check which currency and version a figure refers to.
How many companies are in the MSCI World?
It changes over time. MSCI's factsheet listed 1,280 constituents as of August 31, 2026.
Sources
Grade A = primary source (regulator, government agency, official rulebook or the index provider's own documents). Numbers in brackets in the text point here.
- MSCI. MSCI World Index (USD) factsheet, as of August 31, 2026 (2026). Accessed 2026-10-03.A
- MSCI. MSCI Global Investable Market Indexes Methodology (May 2025 edition) (2025). Accessed 2026-10-03.A
- MSCI. MSCI World Index (2026). Accessed 2026-10-03.A
- MSCI. Market Classification (2026). Accessed 2026-10-03.A
- MSCI. Q&A: Quarterly Comprehensive Index Review Implementation (2022). Accessed 2026-10-03.A
- MSCI. MSCI World Index (EUR) factsheet — price returns (2026). Accessed 2026-10-03.A
- U.S. SEC — Investor.gov. Index Funds (2026). Accessed 2026-10-03.A
This page is general education, not personal financial, tax or legal advice. Figures in worked examples are hypothetical and calculated before taxes and fees unless stated. Rules and limits change; check the linked primary sources for the current version. How we check every page.
