What Is IOO? iShares Global 100 ETF
Last updated September 2026
Short answer
IOO is iShares Global 100 ETF, an ETF that tracks the S&P Global 100 Index at a 0.40% expense ratio. IOO tracks the S&P Global 100, a list of very large multinational companies. In practice the market value of those multinationals is overwhelmingly American: nine of the ten largest positions are US-listed, with Samsung Electronics at 2.7% the sole exception. Technology reaches 45% of the fund and the top ten come to roughly 57% of assets, with Alphabet occupying two of those slots. Anyone buying IOO for international diversification is buying something closer to a US mega-cap fund. It charges 0.40%, well above category norms, on $8.5B.
IOO is issued by iShares and tracks the S&P Global 100 Index. It charges a 0.40% expense ratio, holds approximately $8.5B in assets under management, yields about 0.85%, and launched in 2000.
Global by mandate, American by weight
The top of the fund reads NVIDIA at 12.3%, Apple at 10.8%, Microsoft at 7.0%, Amazon at 5.9%, Alphabet Class A at 5.3%, Broadcom at 4.5% and Alphabet Class C at 4.2%. Every one of those is a US company. Samsung Electronics at 2.7% is the first non-US name, followed by Eli Lilly at 2.4% and JPMorgan at 2.2%, both American again.
This is not a flaw in the index construction. It is what happens when you select the hundred largest multinational companies by market value in a period when American technology companies are the largest in the world by a wide margin. The index is doing exactly what it says. The problem is the gap between what the word global suggests to a buyer and what the resulting portfolio contains.
For an investor whose goal is exposure outside the United States, IOO does not solve the problem. It concentrates the same companies that already dominate any US index, then charges more for the privilege. A dedicated international fund holding companies domiciled outside the US addresses that goal directly.
The concentration is severe even by mega-cap standards
Roughly 57% of the fund sits in its ten largest positions, and once the two Alphabet share classes are combined into a single 9.5% exposure, that is nine companies. NVIDIA alone at 12.3% is more than an eighth of the fund. Technology at 45% is close to half the portfolio before you add the communication services weight of 11%, which is largely Alphabet and its peers.
The remaining sectors are thin by comparison: financials at 10%, healthcare at 9% and consumer discretionary at 8%. A hundred holdings sounds diversified. The weight distribution says otherwise, and the weight distribution is what determines how the fund behaves.
Practically, IOO's day-to-day movement is set by a small number of semiconductor and platform technology companies. That can be exactly what someone wants, but it should be a decision rather than a surprise discovered after a sector drawdown.
The fee is the hardest part to justify
At 0.40%, IOO costs many times what plain large-cap index funds charge, and it has done since launching in 2000. Index funds tracking broad US or global benchmarks have repriced dramatically over that period, and this one has not moved with them. For a rules-based fund holding a hundred of the world's largest and most liquid companies, there is very little in the process that a higher fee is buying.
The 0.85% yield is low, following naturally from a portfolio dominated by technology companies that reinvest earnings and return cash largely through buybacks.
IOO is the wrong tool for international diversification, and an expensive tool for mega-cap exposure. It has a narrow legitimate use: an investor who specifically wants the world's largest multinationals as a single defined list, weighted by size, and is indifferent to the fee. Anyone whose real goal is either broad global equity exposure or cheap US large-cap exposure has better-fitting and cheaper options for both.
IOO holdings: top 10
Approximate weights as of August 2026. Each ticker links to its individual stock guide in Walnut.
How do I invest in IOO?
There are three common ways to get IOO exposure. Buy shares (or fractional shares) of IOO directly at any major broker that lists it. Hold it as a core position and layer more concentrated ideas on top. Or build it into a thematic portfolio in Walnut, so IOO sits alongside other holdings that express the same thesis, with target weights you can rebalance toward. IOO trades like a stock during market hours, so you buy it the same way you would any listed share.
New to buying funds? See how to buy an ETF, step by step.
Is IOO a good buy?
Whether IOO is a good buy depends less on any single call and more on your time horizon and what you already hold: it tracks the S&P Global 100 Index, so the real question is whether you want that exposure in your mix and at what weight. We walk through valuation, concentration, and what would have to be true for it to outperform from here in is IOO a buy?
The bottom line on IOO
IOO gives you the S&P Global 100 Index exposure in one ticker at a 0.40% expense ratio. Most investors use it as a core holding and layer more concentrated thematic portfolios on top.
More on IOO
Whether IOO is worth buying today depends more on your time horizon and what you already hold than on any single call. We walk through valuation, concentration, and what would have to be true for it to outperform from here in is IOO a buy?
IOO yields 0.85% as of August 2026, paid by passing through the dividends of its underlying holdings. For the payout schedule, history, and how the distributions are taxed, see IOO dividend: yield and schedule.
New to funds like IOO? Start with what an ETF is, then how to buy an ETF, or browse the full guide to ETF investing.
Wondering how IOO fits the portfolio you already own? Walnut is an AI investing app that connects your brokerage read-only and answers questions like that about your actual holdings: overlap, concentration, and how each position tracks the S&P 500. Compare the best AI portfolio analyzers or see the best AI investing apps in 2026.
Investing in IOO with AI
Connect the broker you already use and ask Walnut's AI how IOO fits what you actually hold: what it overlaps with, what it leaves you exposed to, and how it has tracked the S&P 500. Read-only by default, and you approve anything before it reaches your broker.
FAQ
Is IOO a genuinely international fund?
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Only nominally. It selects the largest multinational companies by market value, and that selection currently lands overwhelmingly on US-listed businesses. Nine of the ten largest holdings are American, with Samsung Electronics at 2.7% the only exception. An investor whose objective is exposure to companies outside the United States will not achieve it here and should look at a dedicated international or ex-US fund instead.
How concentrated is the portfolio?
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Very. The ten largest positions total roughly 57% of assets, and because Alphabet appears as two share classes at 5.3% and 4.2%, those ten slots represent nine companies. NVIDIA alone is 12.3% and Apple 10.8%. Technology is 45% of the fund. A hundred holdings is a misleading headline when the weight is distributed this unevenly.
Why is the 0.40% fee notable?
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Because it is many times what broad index funds charge for holding a superset of the same companies. The fund follows a published list of large, liquid multinationals, which is not costly to replicate. Index fund pricing has fallen sharply since IOO launched in 2000 and this fee has not followed. Over a long holding period that difference compounds into a meaningful drag.
How does IOO differ from a total world stock fund?
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A total world fund holds thousands of companies across developed and emerging markets, including mid caps and small caps, weighted by market value. IOO holds a hundred of the largest multinationals. The total world fund still leans American because global market value does, but it carries far more names, far more countries and typically a much lower fee. They are not close substitutes.
Why does Alphabet appear twice?
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The company has two listed share classes and the index holds each separately, at 5.3% and 4.2%. Combined, Alphabet is roughly 9.5% of the fund, which would make it the third largest position. This is standard practice for market-cap-weighted indices and means the top ten holdings list represents nine companies, so effective concentration is slightly higher than the list implies.
What is the fund's yield?
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0.85%, which is low. The portfolio is dominated by technology and communication services companies that reinvest earnings or return cash through share buybacks rather than dividends. That is a structural feature of what the fund holds, not a temporary condition. Investors seeking income from global equities generally look at dividend-screened or value-oriented international funds instead.
Does IOO include emerging markets?
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Only incidentally, through companies that happen to qualify by size. Samsung Electronics is the visible example at 2.7%. The index selects on scale and multinational reach rather than by geography, so emerging market exposure is a byproduct of which companies are large enough to qualify. It is not a deliberate allocation and should not be relied on as one.
Who would reasonably hold this fund?
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Someone who specifically wants the world's largest multinational companies as a single defined list weighted by size, and who accepts the 0.40% cost for that definition. It suits neither an investor seeking cheap US large-cap exposure nor one seeking real international diversification, because other funds do each of those jobs more directly and at lower cost.
What is IOO's expense ratio?
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IOO has an expense ratio of 0.40% per year as of August 2026, charged by iShares and deducted from the fund's value rather than billed to you separately. On a $10,000 position that is roughly $40 a year. Fees compound over time, so on a long-term holding the expense ratio is one of the few return drivers you control. It is worth comparing against other funds that track the S&P Global 100 Index before you choose.
How do I compare IOO to similar ETFs?
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Put a few fields side by side: the expense ratio (fees compound over decades), the index or strategy it tracks, the top holdings and how much they overlap with what you already own, the dividend yield, and the AUM, liquidity, and bid-ask spread that affect trading costs. For index funds, tracking error (how closely it follows its index) and tax efficiency matter too. IOO's figures are above; the full method is in Walnut's guide on how to compare ETFs.
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Walnut is informational, not investment advice. Holdings weights and fund statistics on this page are approximations stamped to August 2026; verify current figures against iShares's fund page or your broker before investing.