MSCI Index: What It Is & Why Global Investors Watch It

What Is the MSCI Index?

The MSCI Index refers to a family of stock market indexes created and maintained by MSCI Inc. (formerly Morgan Stanley Capital International), the world's most influential index provider for international investing. MSCI indexes serve as benchmarks for trillions of dollars in global assets, guiding investment decisions by institutional investors, mutual funds, ETFs, and pension funds worldwide. When investors refer to "the MSCI Index," they typically mean one of the flagship indexes like the MSCI World, MSCI ACWI, or MSCI Emerging Markets Index, each covering different segments of the global equity market.

Understanding MSCI indexes is essential for any investor with international exposure because these indexes determine which countries and stocks are included in the most widely used global investment benchmarks. A stock's inclusion in an MSCI index can trigger billions of dollars in passive capital flows, while exclusion can cause significant selling pressure.

MSCI Inc.: Background and Significance

MSCI Inc. was originally part of Morgan Stanley's Capital International division, which began calculating international equity indexes in the 1960s. The company became independent through a series of transactions and went public in 2007. Today, MSCI is a publicly traded company (ticker: MSCI) that generates revenue primarily from index licensing fees, analytics tools, and ESG (Environmental, Social, and Governance) ratings.

MSCI's dominance in the index world is difficult to overstate. Over $16 trillion in assets are benchmarked to MSCI indexes globally. This means that when MSCI adds or removes a stock, reclassifies a country, or adjusts its methodology, the effects ripple across global capital markets as trillions of dollars in index-tracking investments must adjust.

The company's influence extends beyond indexing. MSCI's ESG ratings have become a standard for sustainable investing, and its risk analytics tools (through the Barra platform) are used by the world's largest asset managers.

Key MSCI Indexes Explained

MSCI maintains a comprehensive family of indexes covering virtually every corner of the global equity market. Here are the most important ones investors should know.

MSCI World Index

The MSCI World Index tracks large-cap and mid-cap stocks across 23 developed market countries. It includes approximately 1,500 stocks and represents roughly 85% of the free-float-adjusted market capitalization of each country's equity market. Despite its name, the MSCI World does not include emerging markets — it covers only developed economies.

Due to the size of the U.S. stock market, the MSCI World is heavily weighted toward American stocks (approximately 70%). Japan, the United Kingdom, France, and Canada are the next largest country weights.

MSCI ACWI (All Country World Index)

The MSCI ACWI is the broadest MSCI index, covering both developed and emerging markets. It includes roughly 2,900 stocks across 47 countries (23 developed and 24 emerging market countries) and aims to represent approximately 85% of the global investable equity market.

The ACWI is the benchmark of choice for investors seeking truly global equity exposure. Because developed markets (especially the U.S.) have much larger market capitalizations than emerging markets, the ACWI still has a dominant U.S. weighting of roughly 63%.

MSCI Emerging Markets Index

The MSCI Emerging Markets (EM) Index tracks large-cap and mid-cap stocks across 24 emerging market countries. It includes approximately 1,400 stocks and is the most widely followed benchmark for emerging market investing.

The EM Index is heavily weighted toward a handful of large emerging economies:

The MSCI EM Index is critical because it determines where billions in passive emerging market fund flows are directed. Countries included in the index receive substantial foreign investment from ETFs and index funds that track it.

MSCI EAFE Index

The MSCI EAFE (Europe, Australasia, and Far East) Index covers developed markets outside North America. It includes approximately 800 stocks across 21 countries and is the oldest and most established MSCI international benchmark, dating back to 1969.

EAFE is the standard benchmark for U.S.-based investors seeking developed market international exposure without doubling up on U.S. stocks they already own. Major ETFs tracking EAFE include the iShares MSCI EAFE ETF (EFA).

How Stocks Are Added to and Removed from MSCI Indexes

MSCI uses a rules-based methodology to determine which stocks qualify for inclusion in its indexes. The process is transparent and follows specific criteria, though MSCI retains some discretion for exceptional cases.

Key inclusion criteria:

• Market capitalization: The stock must meet minimum size requirements. For the MSCI Standard Index (large and mid-cap), a stock generally needs a full market cap of at least $5 billion to $7 billion and a free-float-adjusted market cap of at least $2.5 billion to $3.5 billion (thresholds vary by market).
• Free float: MSCI calculates indexes based on free-float-adjusted market capitalization, meaning only shares available for public trading are counted. Shares held by governments, founding families, or strategic holders are excluded from the calculation.
• Liquidity: The stock must meet minimum trading volume and frequency requirements to ensure that index-tracking funds can buy and sell the stock without excessive market impact.
• Foreign ownership limits: For emerging markets, MSCI considers whether foreign investors can freely access the stock. Restrictions on foreign ownership can reduce or eliminate a stock's index weight.

Rebalancing schedule: MSCI reviews its indexes quarterly (February, May, August, November), with the May and November reviews being the most comprehensive semi-annual rebalancing events. During these reviews, stocks may be added, removed, or have their weights adjusted.

The index inclusion effect: When MSCI announces that a stock will be added to a major index, the stock typically rises in anticipation of the buying pressure from index-tracking funds. Conversely, stocks being removed often decline. This effect can be substantial — in emerging markets, an MSCI addition can trigger hundreds of millions of dollars in passive buying.

Country Classification and Its Significance

MSCI classifies every country into one of four categories: Developed Market, Emerging Market, Frontier Market, or Standalone Market. This classification has enormous economic consequences because it determines which index a country's stocks are included in, directly affecting how much foreign capital flows into that country.

Reclassification events are among the most significant MSCI decisions. When a country is upgraded from Frontier to Emerging Market status, its stocks suddenly become eligible for the MSCI EM Index, which is tracked by trillions in assets. This can trigger massive capital inflows. When South Korea and Taiwan were first included in the MSCI EM Index decades ago, they attracted enormous foreign investment that helped fuel their economic growth.

Conversely, when a country is downgraded (for example, if Argentina was reclassified from Emerging to Standalone due to capital controls), it can trigger significant capital outflows as index funds are forced to sell.

Recent notable classification discussions:

• South Korea and Taiwan have long been debated for potential upgrade to Developed Market status
• China A-shares were partially included in the MSCI EM Index starting in 2018, with gradual weight increases
• Israel was upgraded from Emerging to Developed Market status in 2010
• Saudi Arabia was included in the MSCI EM Index in 2019, attracting billions in foreign investment

ETFs That Track MSCI Indexes

The practical way most individual investors access MSCI indexes is through exchange-traded funds (ETFs) that track them.

Note that Vanguard switched from MSCI to FTSE indexes in 2012 to reduce licensing costs. This is important because FTSE and MSCI classify some countries differently. For example, FTSE classifies South Korea as a developed market while MSCI classifies it as an emerging market. This means VWO (Vanguard's emerging markets ETF) does not include South Korean stocks, while EEM and IEMG (iShares' MSCI-tracking ETFs) do.

MSCI ESG Indexes and Factor Indexes

Beyond traditional market-cap-weighted indexes, MSCI has expanded into specialized index families.

MSCI ESG Indexes screen or weight stocks based on environmental, social, and governance criteria. The MSCI ESG Leaders Index selects the highest-ESG-rated companies in each sector, while the MSCI SRI (Socially Responsible Investing) Index applies stricter exclusions (tobacco, weapons, fossil fuels). These indexes have grown dramatically as ESG investing has become mainstream.

MSCI Factor Indexes target specific investment factors that academic research has linked to excess returns:

How MSCI Indexes Affect Individual Investors

Even if you never directly invest in an MSCI-tracking fund, MSCI indexes affect your portfolio in several ways.

Benchmark comparisons. When you evaluate a mutual fund or portfolio manager's performance, it is often compared to an MSCI benchmark. An international fund that underperforms the MSCI EAFE consistently may not be worth its fees.

Capital flows. MSCI index changes drive massive capital flows that move individual stock prices. If you own a stock that is added to or removed from an MSCI index, your position will be affected by the resulting buying or selling pressure.

Country allocation. MSCI's country classification determines how global capital is distributed across economies. This affects exchange rates, interest rates, and economic growth in those countries, indirectly influencing global market conditions.

Portfolio construction. Understanding MSCI index composition helps you identify gaps in your portfolio. If your international allocation only includes an EAFE fund, you are missing emerging markets entirely. If you own only an MSCI World fund, you still lack emerging market exposure despite the word "World" in the name.

Frequently Asked Questions

What is the difference between MSCI World and MSCI ACWI?

The MSCI World Index includes only developed market countries (23 countries), while the MSCI ACWI (All Country World Index) includes both developed and emerging markets (47 countries). ACWI is the broader index that adds approximately 1,400 emerging market stocks to the MSCI World universe. For investors who want a single index covering the global equity market, ACWI is more comprehensive. However, because emerging markets represent only about 10% to 12% of ACWI by weight, the performance difference between MSCI World and ACWI is often modest.

Why does MSCI classification matter for emerging markets?

MSCI classification matters because it directly controls the flow of passive investment capital. When a country is classified as an Emerging Market by MSCI, its stocks are included in the MSCI EM Index, which is tracked by over $1.8 trillion in assets. Index-tracking funds must buy stocks from included countries and sell stocks from excluded countries. This makes MSCI classification a powerful determinant of foreign investment flows, stock market liquidity, and even a country's cost of capital. Governments actively lobby MSCI for favorable classification decisions because the economic stakes are so high.

Is the MSCI Emerging Markets Index a good investment?

The MSCI EM Index provides exposure to faster-growing economies with younger populations, rising middle classes, and lower starting valuations than developed markets. Over the long term, emerging markets have the potential for higher returns but with higher volatility, political risk, and currency risk. Whether it is a "good" investment depends on your time horizon and risk tolerance. A 5% to 15% allocation to emerging markets is standard for a globally diversified portfolio, providing meaningful diversification benefits even if returns vary from year to year.

How often does MSCI rebalance its indexes?

MSCI conducts quarterly reviews in February, May, August, and November, with changes implemented at the end of those months. The May and November reviews are the most comprehensive semi-annual rebalancing events, where MSCI considers additions, deletions, and country reclassifications. The February and August reviews are smaller, typically involving only minor adjustments. MSCI announces changes approximately two to three weeks before implementation, giving the market time to adjust.

Why did Vanguard switch from MSCI to FTSE indexes?

Vanguard switched its international index funds from MSCI to FTSE benchmarks in 2012 primarily to reduce costs. MSCI's index licensing fees were higher than FTSE's, and the switch allowed Vanguard to lower expense ratios for its international funds. The most significant practical difference is in country classification: FTSE classifies South Korea as a developed market while MSCI considers it an emerging market. This means Vanguard's VWO (Emerging Markets ETF) excludes South Korean stocks, while iShares' EEM (which tracks MSCI) includes them. Investors should be aware of this difference when comparing international funds from different providers.