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IOO vs SPY: Differences, Returns & Fees

IOO and SPY hold 51% of their weight in the same names, and IOO returned +21.1% over the year. Net assets: $9.4bn on Oct 9, 2026 for iShares Global 100 ETF, and $817.2bn on Oct 8, 2026 for SPDR S&P 500 ETF Trust.

SPY costs 0.31 points a year less; their one-year returns differ by 3.8 points; SPY is far larger, $817.2bn against $9.3bn.

IOO vs SPY: Differences, Returns & Fees
IOOSPY
Expense ratio0.40%0.09%
Net assets, as of Oct 8, 2026$9.3bn$817.2bn
Total return, 1 year+21.1%+17.3%
What it tracksS&P Global 100S&P 500 Index
Holdings in common51%
Top ten holdings, share of the fund59.9%39.1%

Holdings in common uses holdings dated Oct 8, 2026 and Oct 9, 2026.

+21.1%
IOO total return, 1 year
+17.3%
SPY total return, 1 year
0.40%
IOO expense ratio
0.09%
SPY expense ratio

What they hold in common

By the books each fund has filed, IOO and SPY hold 51% of their money in the same securities at the same weight. Above 50%, holding both is close to holding one of them twice. Holdings dated Oct 8, 2026 and Oct 9, 2026.

half

51% in common

Positions both hold, largest shared weight first
Holding IOO SPY
NVIDIA 13.21% 8.34%
APPLE 11.70% 7.42%
MICROSOFT 9.46% 5.80%
AMAZON.COM INC 6.13% 3.73%
ALPHABET CLASS A 4.91% 3.06%
BROADCOM INC 4.10% 2.56%
ALPHABET CLASS C 3.94% 2.45%
ELI LILLY 2.25% 1.40%
JPMORGAN CHASE & CO 2.11% 1.32%
EXXONMOBIL HOLDINGS CORP 1.65% 1.04%
JOHNSON & JOHNSON 1.50% 0.92%
INTEL CORPORATION 1.24% 0.80%
Only in IOO
SAMSUNG ELECTRONICS LTD 2.12%
ASML HOLDING 1.65%
TENCENT HOLDINGS 0.80%
HSBC HOLDINGS PLC 0.75%
SHELL 0.69%
MITSUBISHI UFJ FINANCIAL GROUP 0.62%
NOVARTIS AG 0.62%
ASTRAZENECA PLC 0.58%
Only in SPY
META PLATFORMS INC CLASS A 2.38%
MICRON TECHNOLOGY INC 1.75%
TESLA INC 1.58%
ADVANCED MICRO DEVICES 1.51%
BERKSHIRE HATHAWAY INC CL B 1.42%
VISA INC CLASS A SHARES 0.96%
ABBVIE INC 0.72%
PALANTIR TECHNOLOGIES INC A 0.68%

Check overlap with more funds →

On the same fields

IOO
iShares Global 100 ETF
SPY
SPDR S&P 500 ETF Trust
Where it sits Stock ETF Stock ETF
Issuer iShares State Street
What it is Tracks an index Tracks the S&P 500
Total return, 1 year +21.1% +17.3%
Its benchmark over the same days not published +17.3% (VOO)
Gap to its benchmark not available −0.1 pts vs VOO
Expense ratio 0.40% 0.09%
Already in the S&P 500 79.0% 99.8%
Holdings 104 504
Net assets, IOO as of Oct 9, 2026 and SPY as of Oct 8, 2026 $9.4bn $817.2bn

IOO and SPY on the fields both publish, as of Oct 9, 2026. Source: ETFIQ.

About IOO

IOO tracks an index. Over the year to Oct 9, 2026 it returned +21.1% with distributions reinvested. The prospectus expense ratio is 0.40% a year. By its holdings published by its issuer for Oct 9, 2026, 79% of the fund by weight is stocks the S&P 500 also holds, across 104 positions, with the top ten at 59.9%.

About SPY

SPY tracks the S&P 500. Over the year to Oct 9, 2026 it returned +17.3% with distributions reinvested, against +17.3% for its benchmark, the S&P 500 Index. The prospectus expense ratio is 0.09% a year. By its holdings published by its issuer for Oct 8, 2026, 100% of the fund by weight is stocks the S&P 500 also holds, across 504 positions, with the top ten at 39.1%.

Questions people ask

Which returned more over the last year, IOO or SPY?
In the year to Oct 9, 2026, with distributions reinvested, IOO returned +21.1% and SPY +17.3%.
Which is cheaper, IOO or SPY?
SPY is cheaper, by 0.31 percentage points a year. That is about $31 on $10,000 held for a year. Fees come from each fund's prospectus.
How much do IOO and SPY overlap with the S&P 500?
By their latest filed holdings, 79% of IOO and 100% of SPY by weight is stocks the S&P 500 already holds.
Other comparisons
IOO vs IVVIOO vs VTIIOO vs VOOIOO vs SPYMSPY vs THRORECS vs SPYSCHK vs SPYSPY vs USMC
IOO on its own →SPY on its own →Hold both: look the portfolio through →Rankings →Standards and sources →
Where these figures came from
IOO filings on SEC EDGAR ↗IOO prospectus with the expense ratio (SEC) ↗iShares page for IOO ↗SPY filings on SEC EDGAR ↗State Street website ↗

ETFIQ links to the documents behind every figure; a link is not an endorsement. A comparison is not a recommendation.

How this is computed

Overlap adds up the smaller of the two weights for each security both funds hold.

Cite this pageCitation, APA and Markdown

ETFIQ, IOO against SPY, data as of Oct 9, 2026. https://etfiq.com/compare/any/ioo-vs-spy

Open data

Free to use with attribution for figures ETFIQ computes; issuer data stays under its owner's terms.