index
MSCI World IMI
Developed-market equities including small caps
Index Battle · Evidence-first comparison
MSCI World IMI vs S&P 500: Which Exposure Fits Your Portfolio?
One index reaches down to developed-market small caps across 23 countries. The other stops at the largest US companies.
Last reviewed: 26 August 2026IndependentNo paid placementsInformational only
vs
index
S&P 500
US large-cap equities
Overall verdict
This is the widest structural gap among the mainstream developed-market choices: MSCI World IMI targets roughly 99% of the free-float market capitalisation of each developed market, including the small-cap segment, while the S&P 500 is a committee-selected set of large US companies. The decision is about how much of the developed equity market the portfolio should attempt to own.
Quick Decision
Choose MSCI World IMI if…
you want the small-cap segment included by rule rather than added later as a separate satellite holding.
Choose S&P 500 if…
the intended exposure is US large-cap corporate earnings, and small caps and non-US markets are handled elsewhere or deliberately excluded.
Either can make sense if…
the decision is documented as an exposure choice, since small caps historically bring different volatility and liquidity characteristics.
At a glance
Entity characteristics—not reference-product fees.
| Characteristic | MSCI World IMI | S&P 500 |
|---|---|---|
| Exposure | Developed-market equities including small caps | US large-cap equities |
| Geography | Developed markets worldwide | United States |
| Market coverage | Large, mid and small cap | Large cap |
| Emerging markets | Not included | Not included |
| Small caps | Included | Not included |
| Weighting | Market-cap weighted | Market-cap weighted |
| Index provider | MSCI | S&P Dow Jones Indices |
Five key differences
- 1.Exposure: Developed-market equities including small caps compared with US large-cap equities.
- 2.Geography: Developed markets worldwide compared with United States.
- 3.Market coverage: Large, mid and small cap compared with Large cap.
- 4.Small caps: Included compared with Not included.
- 5.Index provider: MSCI compared with S&P Dow Jones Indices.
Decision scorecard
ExposureDepends
GeographyDepends
Market coverageDepends
Small capsDepends
Index providerDepends
“Depends” means the category reflects an investor objective, not universal superiority.
Coverage, countries and sectors
Verified holdings, concentration, country and sector datasets are not currently connected. When available, each dataset will be labelled as official index data or Reference ETF holdings; listing domicile will not be presented as economic revenue exposure.
What this means in a portfolio
MSCI World IMI already contains the S&P 500's companies. Holding both is a US large-cap tilt on top of a broad developed core, not a way of adding an asset class.
Common mistake
Assuming the small-cap segment materially changes the portfolio. It usually accounts for a low-to-mid single-digit share of an IMI index, so the ex-US allocation is the more consequential difference.
Historical comparison basis
Historical performance is represented using Grovcap-selected reference exchange-traded products. It is not the official index or spot return series. Fund or ETP returns can differ because of fees, taxes, tracking, cash positions, product structure and other implementation effects. Differences can reflect TER, tracking difference, withholding taxes, sampling, securities lending, cash drag, operating expenses, currency conversion and inception date.
No period is currently comparable across both reference products on a like-for-like currency, basis and reporting-date footing, so no return figures are shown. Grovcap never renders a missing return as 0.00%.
Grovcap does not currently hold a daily net-asset-value time series for these products. Indexed performance charts, annualised volatility, maximum drawdown and return-per-risk therefore remain unavailable rather than being estimated from period returns.
Reference instruments used
One canonical European exchange-traded product per exposure, chosen by published rules: exact benchmark family, active and published, plain long-only, then accumulating, unhedged, longest usable history and largest established product.
MSCI World IMI reference product
Xtrackers MSCI World IMI UCITS ETF 1C
- ISIN
- IE000X1GW0A7
- Product type
- UCITS ETF
- Provider
- Xtrackers
- Tracked benchmark
- MSCI World IMI Index
- Distribution
- Accumulating
- Currency hedging
- Unhedged
- Replication
- Physical
- Domicile
- IE
- Base currency
- USD
- Ongoing charge (TER)
- 0.15%
- Fund size
- €12.26m
- Inception
- 8 Apr 2026
Selected deterministically from 1 eligible product in the Grovcap database — never by commercial arrangement.
S&P 500 reference product
Xtrackers S&P 500 Swap UCITS ETF 1C
- ISIN
- LU0490618542
- Product type
- UCITS ETF
- Provider
- Xtrackers
- Tracked benchmark
- S&P 500 INDEX
- Distribution
- Accumulating
- Currency hedging
- Unhedged
- Replication
- Synthetic
- Domicile
- LU
- Base currency
- USD
- Ongoing charge (TER)
- 0.15%
- Fund size
- €8.17bn
- Inception
- 26 Mar 2010
Selected deterministically from 49 eligible products in the Grovcap database — never by commercial arrangement.
Continue researching
Related Grovcap guides, rankings and tools to take the next step.
Best ETFsBest MSCI World UCITS ETFsEvery plain MSCI World UCITS share class compared on cost, size and structure.Best ETFsBest S&P 500 UCITS ETFsEvery S&P 500 UCITS share class compared on cost, size and structure.ETF comparisonVWCE vs SPYIGlobal large- and mid-cap exposure versus an investable-market index with small caps.BenchmarkS&P 500 benchmark guideUnderstand the coverage and limits behind S&P 500 ETFs.ETF comparisonCSPX vs VUAATwo accumulating Irish-domiciled S&P 500 trackers compared side by side.
Disclaimer
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