MSCI World, FTSE All-World or ACWI? Compared
July 22, 2026
5 min read
MSCI World, FTSE All-World or ACWI — Which World Index?
What separates the three, what they share, and what actually matters from a Swiss perspective.
The short version
- The biggest difference is emerging markets. The MSCI World excludes them; ACWI and FTSE All-World include them, at a low double-digit percentage weight.
- The second difference is breadth. FTSE All-World holds the most constituents, MSCI World the fewest. More holdings do not automatically mean more diversification, because the additional names carry tiny weights.
- Return differences have historically been smaller than the debate suggests. All three are dominated by the same very large companies.
- From a Swiss perspective something else matters more: fund domicile, stamp duty and FX surcharges affect your outcome more than the choice between these three.
01What the three indices cover
All three represent the global equity market, with different reach.
| MSCI World | MSCI ACWI | FTSE All-World | |
|---|---|---|---|
| Developed markets | yes, 23 | yes, 23 | yes |
| Emerging markets | no | yes | yes |
| Small caps | no | no | no |
| Number of holdings | fewest | middle | most |
| US weight | highest | slightly lower | slightly lower |
Holding counts and country weights change continuously with market capitalisations. Current figures belong in the factsheet of the specific fund, not in an article.
The MSCI World is the narrowest: developed markets, large and mid caps. No China, no India, no Brazil.
The MSCI ACWI takes those same developed markets and adds emerging ones. It is effectively the MSCI World plus emerging markets in one instrument.
The FTSE All-World also covers both, but draws the line between mid and small caps differently and therefore holds more individual names. FTSE also classifies some countries differently from MSCI — South Korea is the best-known example.
02Why the differences are smaller than they look
All three weight by market capitalisation. That means the world's largest companies dominate each of them — and they are the same companies in all three.
The emerging markets share in ACWI and All-World sits in the low double digits. Even if those markets run very differently from developed ones for a year, it shifts the overall return by only fractions of a percent. The extra holdings in FTSE All-World carry even smaller weights and barely register.
The honest framing
Over long periods the three have tracked closely. Sometimes one led, sometimes another, depending on whether emerging markets were outperforming. Anyone holding one of these for thirty years will not be able to attribute the outcome to the index choice.
03What actually matters
If the index choice matters little, what matters a lot? Four things, none of them connected to World versus ACWI versus All-World.
Fund domicile. An Irish-domiciled fund pays 15% instead of 30% withholding tax on US dividends. Because US equities are the largest block in all three indices, that is worth roughly 0.15% to 0.19% a year — considerably more than the typical return gap between the indices. Details in Irish ETFs: 15% Instead of 30%.
Tracking difference. It measures how far the fund's actual return deviates from the index and contains more than the TER. Two funds on the same index can differ noticeably here.
The costs around buying. FX surcharges and stamp duty apply to every contribution. In a savings plan they weigh on the result permanently, whichever index you chose.
Whether you stay invested. The biggest lever of all, and the one no index debate addresses.
04Which suits whom?
You want maximum simplicity and accept that emerging markets are missingMSCI World
You want emerging markets in a single instrumentACWI or All-World
You want the broadest holding coverageFTSE All-World
You want to control the emerging markets weight yourselfMSCI World plus a separate EM block
The last option is the most work, because it requires rebalancing — and rebalancing costs stamp duty, spread and currency conversion. Why one position is often cheaper than several is covered in A World Equity Portfolio.
What we use
The arvy ETF Savings Plan covers the entire world, but not through a single fund: roughly 88% developed markets and roughly 12% emerging markets, matching the weighting in the ACWI. The reason is price — two blocks cost 0.06% together against 0.12% to 0.20% for a single-fund solution. The details are on The Building Blocks.
05Frequently asked questions
What is the difference between MSCI World and MSCI ACWI?
The ACWI additionally includes emerging markets; the MSCI World covers developed markets only. Otherwise the methodology and the largest holdings are largely identical. The emerging markets share in the ACWI sits in the low double digits.
What is the difference between MSCI ACWI and FTSE All-World?
Both cover developed and emerging markets. FTSE All-World holds more individual names because FTSE draws the small-cap boundary differently, and it classifies some countries differently from MSCI. Return differences have historically been small.
Do I need emerging markets in my portfolio?
Not necessary, but it can be sensible. A developed-markets index leaves out a significant part of the world economy. On the other hand, many of the large index companies already generate revenue globally. If you want emerging markets, ACWI or All-World delivers them in one instrument.
Should I buy MSCI World and emerging markets separately?
That allows your own weighting but requires regular rebalancing. Every reallocation costs stamp duty, spread and possibly currency conversion. If you do not want to steer the weighting deliberately, one instrument is simpler and cheaper.
Which index performed best historically?
Entirely dependent on the period. Sometimes developed markets led, sometimes emerging ones. Because all three are dominated by the same large companies, differences over long periods were small. No forecast can be derived from it.
Does the index choice matter much at all?
Less than most assume. Fund domicile, tracking difference, FX surcharges and above all your own staying power affect the final result more than choosing between these three indices.
Keep reading
We made the choice for you
The arvy ETF Savings Plan covers developed and emerging markets — 0.39% management plus 0.06% product costs.
This article was written by Thierry Borgeat, co-founder of arvy, and reviewed by Patrick Rissi, CFA, and Florian Jauch, CFA.
Disclaimer: arvy AG is a manager of collective assets authorised by FINMA under Art. 24 CISA. This article is for information purposes only and constitutes neither investment advice nor tax or legal advice. All amounts are indicative and depend on canton, municipality and personal circumstances. Past performance is not a reliable indicator of future results.
