IOO vs SPY
iShares Global 100 ETF vs State Street SPDR S&P 500 ETF Trust
Which is better, IOO or SPY?
Nearly the same fund. SPY costs less.
SPY has a lower expense ratio. IOO led over 1Y, 3Y and 5Y, SPY over the full window. The two have moved almost in lockstep, correlation 0.95. SPY is less concentrated, with 37.8% of the fund in its ten largest positions against 58.7%.
MarketXLS is not an investment adviser. This comparison is generated automatically from market data and is for information only. A Best mark means the better reading on that one measure, not a recommendation to buy.
Side-by-Side Comparison
| Metric | IOO | SPY |
|---|---|---|
| Expense Ratio | 0.40% | 0.09%Best |
| AUM | $9.1B | $804.7B |
| Dividend Yield | 0.81% | 0.98% |
| Holdings | 117 | 505 |
| YTD Return | +14.21%Best | +12.99% |
| 1Y Return | +22.36%Best | +16.73% |
| 3Y Return (annualized) | +26.32%Best | +22.52% |
| 5Y Return (annualized) | +16.07%Best | +13.07% |
| Volatility (annualized) | 15.8% | 15.1%Best |
| Max Drawdown | -57.9% | -56.5%Best |
| $10,000 over 5 years | $21,067Best | $18,481 |
| Top 10 Weight | 58.7% | 37.8%Best |
| Fund Family | iShares by BlackRock (US) | State Street Investment Management |
| Category | Equity | Equity |
| Style | Large Cap Blend | Large Cap Blend |
| Inception | Dec 5, 2000 | Jan 22, 1993 |
Volatility and max drawdown are measured over the window both funds cover: Dec 8, 2000 to Sep 23, 2026 (25.8 years).
IOO vs SPY growth
Month-end closes. Both lines start at 0% in the first month shown, so the gap between them is the difference in growth across that window. The full view covers the 25.8 years both funds cover.
IOO vs SPY Performance
iShares Global 100 ETF (IOO) is an ETF from iShares by BlackRock (US) and State Street SPDR S&P 500 ETF Trust (SPY) is an ETF from State Street Investment Management. Over the past year IOO returned +22.36% while SPY returned +16.73%. Year to date, IOO is up 14.21% versus a gain of 12.99% for SPY.
Over three years, IOO compounded at +26.32% per year against +22.52% for SPY; over five years the annualized figures are +16.07% and +13.07% respectively. Across the full 26-year window we track, SPY has the edge at +7.31% annualized vs +5.82%.
Past performance does not guarantee future results.
Risk: Volatility and Drawdowns
IOO has been the more volatile fund, with annualized monthly volatility of 15.8% compared with 15.1% for SPY. Lower volatility generally means a smoother ride, though it often comes with lower long-run returns.
The deepest peak-to-trough decline in our data was -57.9% for IOO and -56.5% for SPY. Drawdown depth is what each fund did in the worst stretch of the window measured above.
The two funds' monthly returns correlate at 0.95. They move almost in lockstep, so holding both mostly duplicates the same exposure.
Fees and Cost Over Time
IOO charges 0.40% per year while SPY charges 0.09%. On a $10,000 position that is $40 vs $9 annually, a gap of $31 per year that compounds over a long holding period. On income, IOO currently yields 0.81% against 0.98% for SPY.
Holdings Overlap
80.2% of IOO's money is in holdings SPY also owns. 50.2% of SPY's money is in holdings IOO also owns.
Most of IOO is already inside SPY. Owning both mostly buys the same companies twice.
51 positions in common, counted across the 102 positions we hold weights for in IOO and 504 in SPY, against full books of 117 and 505.
What only one of them owns
Our book lists 446 positions for SPY that do not appear in our book for IOO (49.2% of the fund), and 5 for IOO that do not appear in SPY (3.5%).
Some of those will be the same company recorded under a different code in one of the two books, so the real difference in what you would own is no larger than this and may be smaller. We do not name the individual positions here for that reason.
Top Shared Holdings
| Stock | Weight in IOO | Weight in SPY | Difference |
|---|---|---|---|
| NVDANvidia Corp | 12.85% | 8.01% | 4.84% |
| AAPLApple, Inc | 11.18% | 7.26% | 3.92% |
| MSFTMicrosoft Corp | 9.05% | 5.66% | 3.39% |
| AMZNAmazon.Com Inc | 6.11% | 3.79% | 2.32% |
| GOOGLAlphabet Inc,class A | 4.78% | 2.99% | 1.79% |
| AVGOBroadcom Inc | 4.21% | 2.66% | 1.55% |
| GOOGAlphabet Inc | 3.81% | 2.39% | 1.42% |
| JPMJpmorgan Chase | 2.28% | 1.45% | 0.83% |
| LLYEli Lilly & Co. | 2.20% | 1.40% | 0.80% |
| XOMExxon Mobil Corp. | 1.60% | 1.04% | 0.56% |
80.2% of IOO is already inside SPY.
You probably hold more than these two. Add the rest and see how much of the whole book is the same companies twice.
Free for up to 10 holdings. No account needed.
Frequently Asked Questions
Which is cheaper, IOO or SPY?
IOO has an expense ratio of 0.40% while SPY charges 0.09%. SPY is the cheaper option, by $31 a year on a $10,000 investment.
Which performed better, IOO or SPY?
Over the past year IOO returned +22.36% vs +16.73% for SPY, so IOO leads on 1-year performance. Over the longest common window we track (26 years), IOO annualized +5.82% vs +7.31% for SPY. Past performance does not guarantee future results. This is information, not a recommendation.
Which is riskier, IOO or SPY?
IOO has been the more volatile fund at 15.8% annualized versus 15.1% for SPY. Worst drawdown: IOO -57.9% vs SPY -56.5%.
Should I hold both IOO and SPY?
IOO and SPY have a monthly-return correlation of 0.95, so they move almost identically. What is left to separate them is the fee and the index each one tracks. This is information, not a recommendation.
What is the holdings overlap between IOO and SPY?
80.2% of IOO's money is in holdings SPY also owns. 50.2% of SPY's is in holdings IOO also owns. They hold 51 positions in common, counted across the 102 positions we hold weights for in IOO and 504 in SPY.
Which pays a higher dividend, IOO or SPY?
IOO yields 0.81% while SPY yields 0.98%, so SPY currently pays the higher dividend yield.
Is SPY better than IOO?
SPY has a lower expense ratio. IOO led over 1Y, 3Y and 5Y, SPY over the full window. The two have moved almost in lockstep, correlation 0.95. SPY is less concentrated, with 37.8% of the fund in its ten largest positions against 58.7%. Which one suits a particular account depends on what it is for. This is information, not a recommendation.