An index can include developed and emerging markets without holding every listed company or giving every country the same weight. MSCI’s rules — the GIMI methodology, August 2026 edition and the market classification framework, read in full — explain what ACWI adds to World and where its boundaries lie.
At a glance. MSCI ACWI brings together large and mid cap companies from markets MSCI classifies as developed and emerging. In the 31 August 2026 factsheet, it has 2,458 securities across 23 developed and 24 emerging markets. MSCI says it covers approximately 85% of the global investable equity opportunity set. The definition of that opportunity set matters as much as the percentage.
MSCI’s best known index is the World, covered by our guide and the “Inside the indexes” series. But MSCI also builds other global equity indexes, with different coverage:
What changes from MSCI World
“World” sounds like the entire world. In MSCI’s index family, it covers developed markets. ACWI, the All Country World Index, adds emerging markets while retaining large and mid cap companies. On the same date, World has 1,280 securities and ACWI 2,458. The count tells us how many securities are represented, not how much of the index they weigh.
The weight row of the table explains why: not an equal slice per market, not GDP, but market value adjusted for free float. Additional securities can therefore change the constituent count much more than they change overall weight. In the 31 August 2026 snapshot, the US weighs 72.14% in World and 63.59% in ACWI. Including emerging markets lowers its share without removing concentration.
Country, company, security: three different things
A company may sell around the globe, but MSCI assigns its securities to a country under its classification rules. A country’s index weight therefore describes exposure to companies classified in that market, not the origin of their revenue or the size of its economy. The same company may have securities with different listings and different levels of access for investors. These distinctions matter whenever a chart says “China weight” or “US weight”.
Before assigning weights, MSCI builds an eligible universe in each market. It examines size, trading activity, the available float, remaining room for foreign investors and other requirements; it then divides companies into large, mid and small cap segments. Continuity rules and buffer zones help avoid frequent entries and exits caused by small changes. This is a rules based construction process, not a manager choosing the “best” companies.
Here is a simple illustration of free float. If a company’s total market value is €10 billion and 40% of its shares are available to investors, its starting float adjusted value is €4 billion, before any further inclusion factor. The example illustrates arithmetic; it is not an actual constituent or a universal weighting rule.
China in ACWI: what are A shares and H shares?
A share is a small ownership stake in a company. Chinese companies can have shares listed in different markets: A shares trade in Shanghai and Shenzhen, in mainland China; H shares trade in Hong Kong. The same company can have both. The letters tell us which shares we are looking at and where they are listed.
This matters for ACWI because MSCI does not automatically include every share of every Chinese company. For A shares, one of its checks is whether international investors can access them through Stock Connect, the link between Hong Kong and mainland China’s stock exchanges. H shares have their own selection rules.
Then there is the 20% figure, which applies to eligible large and mid cap A shares (GIMI methodology, August 2026 edition). MSCI first looks at the portion of shares available for investors to trade, known as the free float. For these A shares, it then counts 20% of that value when calculating the index. A simplified example: if the tradable portion of a share class were worth 100, MSCI would count 20 when calculating its index weight. This does not mean China makes up 20% of ACWI, or that only 20% of Chinese companies can be included.
So “China is in ACWI” is true. “ACWI includes the entire Chinese stock market” would mean something different.
What “All Country” leaves out
ACWI covers large and mid cap securities. Small cap companies sit outside it. MSCI ACWI IMI adds that size segment and has 8,162 constituents in the 31 August 2026 factsheet. MSCI describes ACWI IMI as covering approximately 99% of its global investable equity opportunity set. IMI still applies investability requirements: broader coverage does not mean every listed company.
ACWI also excludes markets MSCI classifies as frontier or standalone, as well as securities that fail the rules within included markets. Classification follows a framework covering economic development, market size and liquidity, and accessibility for international investors. South Korea, for example, is classified as an emerging market by MSCI. This is a market classification, not an assessment of the quality of Korean companies.
The categories can change. In its 2026 review, MSCI announced a planned move of Greece from emerging to developed status at the May 2027 index review. Greece was still an emerging market in the 31 August 2026 factsheet. An announcement and its implementation are separate events; this dated example will be updated when MSCI confirms the change.
More countries does not mean equal diversification
ACWI’s country chart answers “where are companies classified?”, not “where do they earn their revenue?”. And a larger number of securities does not by itself show how evenly the index is weighted: on 31 August 2026, its top ten securities account for 24.26%. Countries, sectors and individual companies are different views of concentration.
There is no threshold at which an index suddenly becomes “the entire world”. ACWI adds part of the universe absent from World while retaining rules on size, access and weighting. Those rules tell us more than the name on the cover.
ACWI, ACWI IMI and FTSE All-World: similar names, different indexes
ACWI and ACWI IMI are both MSCI indexes; the latter also covers small cap companies. FTSE All-World is built by FTSE Russell and likewise covers large and mid cap companies across developed and emerging markets. But the providers’ methodologies and country classifications differ: ETFs tracking these indexes do not declare the same benchmark. A fund with “ACWI” in its name may also track a screened, sector or currency hedged variant. Its marketing name cannot replace the exact benchmark named in its documentation.
From index to ETF
An index is a calculation framework, not a fund one can buy. A fund selects a way of tracking it and incurs its own costs and operational effects. The table below displays only ETFs whose stated benchmark is the standard MSCI ACWI, with ACWI IMI, screened, thematic and hedged variants kept apart. TER, KID transaction costs, assets and tracking difference come from Rebalix’s issuer sourced register, with its own observation period and date. Tracking difference compares the fund’s actual return with the index variant declared as its benchmark, in the same currency and period. The table is neither a ranking nor a forecast.
8 ETFs in our registry track this index. Below, 6 funds: the largest among those for which we computed the 1-year tracking difference on official NAV series (6 of 8): how much the fund actually returned versus the index, all costs included — often more telling than the TER.
| Fund | Issuer | TER | Transaction costs (KID) | 1y TD | Fund size ▾ | Replication | Income | Milan |
|---|---|---|---|---|---|---|---|---|
| iShares MSCI All Country World UCITS ETFIE00B6R52259 · 3 classes | iShares | 0.20% | 0.01% | +0.08% | 31.5 bn | Physical (optimised) | Acc / Dist | ✓ |
| State Street® SPDR® MSCI All Country World UCITS ETF (Acc)IE00B44Z5B48 | SPDR | 0.12% | 0.00% | +0.16% | 20.0 bn | Physical (optimised) | Acc | ✓ |
| UBS MSCI ACWI SF UCITS ETF USD accIE00BYM11H29 | UBS | 0.21% | 0.00% | -0.05% | 3.9 bn | Synthetic (swap) | Acc | ✓ |
| Amundi MSCI All Country World Swap UCITS ETFLU1829220216 · 2 classes | Amundi | 0.45% | 0.00% | -0.23% | 2.5 bn | Synthetic (swap) | Acc | ✓ |
| Xtrackers Scalable Msci Ac World Xtrackers UCITS ETFLU2903252349 | Xtrackers | 0.15% | 0.04% | +0.27% | 783 m | Synthetic (swap) | Acc | ✓ |
| UBS MSCI ACWI SF UCITS ETF USD UkdisIE00BJXFZ989 | UBS | 0.21% | 0.00% | -0.06% | — | Synthetic (swap) | Dist |
This is a sample: the full picture of the family, with costs and tracking difference, is on the dedicated page → The MSCI ACWI family compared
TD = fund return − index return over the last 12 months, computed by Rebalix on the NAV series published by the issuers and checked against external sources; negative = the fund returned less than the index. Fund size in euro. Funds sorted by fund size. Registry data as of 17 October 2026. Transaction costs (KID) = the issuer’s estimate in the PRIIPs KID: a separate cost item, not included in the TER; the two figures should not be added up as if they were the total cost. “—” = not declared, not a zero. How we compute tracking difference →
Objective data, not a recommendation: which fund suits you depends on your situation.
Returns also depend on which version of an index is shown. Price reflects prices; Gross and Net include dividends under different conventions. MSCI’s international Net version uses the withholding tax assumptions in its calculation methodology, which need not match the tax actually paid by a particular ETF. Where this article shows index returns, the series is MSCI ACWI EUR Net. “EUR” identifies the currency in which the return is expressed; it does not, by itself, mean foreign currency exposure is hedged. Read each fund’s documentation for its precise benchmark.
How this page is maintained
The index snapshot shows its date, 31 August 2026. The ETF comparison has a separate register date, shown under the table. The rules are checked against the cited MSCI methodologies; when a methodology or country classification changes, the editorial text is reviewed and dated. A fresh numerical snapshot does not, by itself, mean the methodology text has been reviewed.
The figures on this page come from the MSCI factsheets of 31 August 2026, which Rebalix archives at their observation date. The official index pages — MSCI ACWI, MSCI World, MSCI ACWI IMI — show current data instead, and change over time: they are the place to verify the figures, not an exact copy of this snapshot.
Frequently asked questions
Does MSCI ACWI include emerging markets?
Yes, alongside developed markets, according to MSCI’s country classification on the snapshot date.
Does ACWI include small cap stocks?
No. Within the MSCI family, ACWI IMI adds that segment, subject to investability screens.
Is MSCI World plus an emerging markets ETF identical to an ACWI ETF?
Not automatically. A comparison needs the exact benchmarks, weights, dates, currency, return variants and fund data. Similar geographic coverage does not make two products identical.
Are ACWI and FTSE All-World the same index?
No. Both cover developed and emerging markets and large and mid cap companies, but different providers build them under different rules.
Does an ACWI index expressed in euros hedge currency risk?
No. Index reporting currency and currency hedging are separate features.
Does a country’s weight tell me where its companies make sales?
No. It combines the securities of companies MSCI classifies in that market; those companies may sell in many other countries.
Why might an ETF’s return differ from ACWI’s return?
Funds have costs, replication choices, taxes, valuation dates and potential deviations from the benchmark. A fair comparison uses the actual index variant named by the fund and the same period.