Market Cap Indexes Intro copy

What are Market Cap Indexes?

Our suite of large, mid and small cap indexes is designed to accurately represent and measure global equity markets as they evolve, meeting a wide range of changing investor needs within a single framework. A company will be classified as large, mid or small cap based primarily on its market capitalization.1

Using a modular approach and a transparent, rules-based methodology, we have constructed a suite of investable indexes, the ACWI IMI (PDF, 180 KB) (opens in a new tab) family, which provides extensive coverage of the global equity investment universe. With no gaps or overlaps, the consistent framework enables investors to define their equity allocations and pursue their investment goals.

A building block approach that’s both flexible and adaptable

In addition to consistent selection and weighting, our methodology applies a modular approach across geographies (country, regions) and index types, such as size and sector. Consequently, investors are able to segment the global investable opportunity in ways that enhance their understanding of key performance drivers. Our building block approach also enables investors to tailor the universe to their needs and incorporate asset allocation views and insights.


How we construct our Indexes

MSCI Global Investable Market Indexes are constructed and maintained with the objective of reflecting the evolution of the world’s equity markets and segments on a timely basis, while remaining replicable and stable.

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Bringing the World Into Focus

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Data as of Jan. 18, 2023 (February index quarterly rebalance)


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Flagship Indexes

Flagship Indexes

Our Market Cap flagship Indexes are used by investors around the globe to define and help structure their equity allocations and portfolios.


    This index captures large, mid and small cap representation across Developed and Emerging Market countries. This comprehensive index covers approximately 99% of the global equity investment opportunity.

  • Developed Markets

    Our suite of Developed Markets Indexes is designed to offer investors a wide range of choices that reflect different regions, countries, size segments and sectors.

  • Emerging Markets Indexes

    Our suite of Emerging Markets Indexes is designed to offer investors a variety of choices that represent different regions, countries, size segments and sectors.

  • China Indexes

    The MSCI China Indexes consist of a range of indexes representing the Chinese markets, intended for both domestic and international investors, including Qualified Foreign Institutional Investors (QFII) licensees.

How our Market Cap Indexes can be used by investors


How our Market Cap Indexes can be used by investors

Our Market Cap Indexes support asset allocation, performance measurement and attribution, research and investment product development.

Click on the use cases below to find out more:

Use cases for Market Cap Indexes - Traditional and Established

Use cases for Market Cap Indexes - traditional and established

Our indexes can help active and passive investors assess the performance of their equity portfolios.

Investors use our indexes as benchmarks to understand how their equity investments are delivering on or falling short of expectations.


MSCI’s suite of ACWI IMI Indexes can be used by asset managers, banks and asset owners to create investment vehicles that reference or relate to our indexes, such as ETFs and mutual funds, as well as more complex structured products.

The growth of indexed investing vehicles has enabled a greater number of investors to participate in equity markets.


Investors can use MSCI’s suite of ACWI IMI Indexes and associated data to enhance their stock level research and gain a deeper understanding of performance and risk drivers at the portfolio level.

The depth and breadth of data available through the ACWI IMI framework supports investors’ decision-making process.


Use cases for Market Cap Indexes – Emerging and Growing

Use cases for Market Cap Indexes – Emerging and Growing

The flexibility and transparency of our construction methodology allows investors to tailor our indexes to meet their specific needs and objectives.

Because they incorporate a comprehensive and detailed representation of what is investable within equity markets, our indexes often are used as a reference for a variety of investment strategies. Investors can save time and resources by relying on our tried-and-tested index construction methodology and governance best practices.

Increasingly we work with asset and wealth managers to create tailored information and portfolios that reflect their clients’ personal circumstances.

As part of our commitment to foster transparency and afford investors greater control of their investment outcomes, we make available the data sets and insights that constitute the core components of our indexes. These help investors better understand how indexes are built and facilitate further customization.

Featured Content

Featured content

Global Investing Trends

Research and Insights

Our investing insights explore the topics that matter most, whether on climate and ESG, current market trends or global investing and risk management across asset classes.


State of Global Investing

State of Global Investing

The interconnectedness of equity markets around the world means they are often affected by geographical proximity, economic development, and market accessibility. Splitting global markets across two dimensions — level of development and geographical position — has resulted in correlation clusters.


Future of Emerging Markets

Future of Emerging Markets

Will emerging markets remain a distinct asset class and will they continue to represent an essential portfolio allocation for international investors?


Unlock Australia's Investment Potential with MSCI Australia Indexes

Unlock Australia's Investment Potential with MSCI Australia Indexes

Building on the MSCI Australian Domestic Module launched in 2020, our latest addition is an enhanced series of AUD-denominated market-cap indexes: the MSCI Australia Listed Indexes.

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Market Cap Indexes Related Content

Market Cap footnotes


1Through our legacy companies KLD, Innovest, IRRC, and GMI Ratings. ESG and climate data, research and ratings are produced by MSCI ESG Research LLC and are used as an input to the MSCI ESG indexes, calculated by MSCI, Inc. For more detailed information about how MSCI constructs its ACWI IMI Indexes, please refer to MSCI Global Investable Market Indexes Methodology (PDF, 1.88 MB) (opens in a new tab)