Direct Answer
The MSCI ACWI ex USA is a rule-based measurement of large- and mid-cap equities across developed and emerging market countries excluding the US, maintained by MSCI. 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 MSCI ACWI ex USA covers large- and mid-cap equities across developed and emerging market countries excluding the US, within the Global market. MSCI defines which securities are eligible, how they are selected from that pool, and how much each one contributes to the published number.
The index name does not state a fixed company count, so the number of constituents follows the eligibility rules rather than a target.
How constituents are weighted
Constituents are weighted by free float-adjusted market capitalization, scaled by the Foreign Inclusion Factor. Because the index is a composite of country indexes with the US market left out, the remaining countries keep the constituents they hold in the parent All Country index and only the weights are rescaled.
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
Large and mid cap (Standard Index) segments of the developed markets other than the US and of the emerging markets. Each market is built to reach about 85% plus or minus 5% of its free float-adjusted coverage, within a global minimum size range of 0.5 to 1.15 times a global reference, so that company sizes are comparable across countries.
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
A new issue must have traded for at least three months before a review to be considered. Large IPOs can be added early, after the close of their tenth trading day, and existing constituents are tested against lower retention thresholds than new names.
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
Quarterly reviews in February, May, August and November. Global minimum size references and ranges are recalculated at each review, and event-related changes between reviews are applied as they occur.
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
Nothing is reselected to compensate for the missing US. MSCI builds every market on its own and forms regional composites from those building blocks, so an ex USA index is a subtraction: its coverage target is applied country by country, not to the combined non-US total.
References
- MSCI: MSCI GIMI Methodology: Index Construction Objectives, Guiding Principles and Methodology for the MSCI Global Investable Market Indexes, as published 2026. Every rule described on this page is taken from this document.
Current MSCI ACWI ex USA constituents
MSCI publishes and licenses the MSCI ACWI ex USA constituent list. Swoopr does not republish it here. The provider's own page is the authoritative source for current membership and weights.
Related reading
- All stock market indexes: how indexes are built, weighted and revised.
- Global indexes: others covering the same region.
- Index concentration: measuring how much of an index sits in its largest holdings.
- Index rebalancing and inclusion effects: what happens to a stock when index membership changes.
Frequently Asked Questions
Who maintains the MSCI ACWI ex USA?
MSCI maintains the MSCI ACWI ex USA and publishes the methodology document that defines its eligibility and weighting rules.
What does the MSCI ACWI ex USA measure?
It measures large- and mid-cap equities across developed and emerging market countries excluding the US. 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 MSCI ACWI ex USA constituents?
MSCI publishes the current constituent list. Swoopr does not republish it, because index providers license constituent data and Swoopr holds no such licence.