GMMF vs VOO
iShares Government Money Market ETF vs Vanguard S&P 500 ETF
Quick Verdict
VOO has a lower expense ratio. VOO delivered stronger 1-year returns. VOO offers more diversification with 509 holdings.
Side-by-Side Comparison
| Metric | GMMF | VOO | Winner |
|---|---|---|---|
| Expense Ratio | 0.20% | 0.03% | |
| AUM | $191M | $997.4B | |
| Dividend Yield | 3.86% | 1.08% | |
| Holdings | 152 | 509 | |
| YTD Return | +2.13% | +12.25% | |
| 1Y Return | +3.63% | +20.92% | |
| 3Y Return (annualized) | - | +21.79% | |
| 5Y Return (annualized) | - | +13.05% | |
| Volatility (annualized) | 0.6% | 14.1% | |
| Max Drawdown | -0.3% | -34.3% | |
| Fund Family | iShares by BlackRock (US) | Vanguard (US) | |
| Category | Money Market | Equity | |
| Inception | Feb 4, 2025 | Sep 7, 2010 |
GMMF vs VOO Performance
iShares Government Money Market ETF (GMMF) is a ETF from iShares by BlackRock (US) and Vanguard S&P 500 ETF (VOO) is a ETF from Vanguard (US). Over the past year GMMF returned +3.63% while VOO returned +20.92%. Year to date, GMMF is up 2.13% versus a gain of 12.25% for VOO.
Risk: Volatility and Drawdowns
VOO has been the more volatile fund, with annualized monthly volatility of 14.1% compared with 0.6% for GMMF. 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 -0.3% for GMMF and -34.3% for VOO. Drawdown depth is worth weighing if you expect to sell during market stress rather than ride it out.
The two funds' monthly returns correlate at 0.12. They move independently enough that combining them can meaningfully diversify a portfolio.
Fees and Cost Over Time
GMMF charges 0.20% per year while VOO charges 0.03%. On a $10,000 position that is $20 vs $3 annually, a gap of $17 per year that compounds over a long holding period. On income, GMMF currently yields 3.86% against 1.08% for VOO.
Holdings Overlap
GMMF and VOO share 0 holdings out of 521 unique holdings combined, representing a 0.0% weight overlap.
Moderate overlap means holding both could provide meaningful diversification benefits.
Frequently Asked Questions
Which is cheaper, GMMF or VOO?
GMMF has an expense ratio of 0.20% while VOO charges 0.03%. VOO is the cheaper option. On a $10,000 investment, that is $17 per year of difference.
Which performed better, GMMF or VOO?
Over the past year GMMF returned +3.63% vs +20.92% for VOO, so VOO leads on 1-year performance. Over the longest common window we track (2 years), GMMF annualized +3.83% vs +13.45% for VOO. Past performance does not guarantee future results.
Which is riskier, GMMF or VOO?
VOO has been the more volatile fund at 14.1% annualized versus 0.6% for GMMF. Worst drawdown: GMMF -0.3% vs VOO -34.3%.
Should I hold both GMMF and VOO?
GMMF and VOO have a monthly-return correlation of 0.12, so combining them can provide real diversification depending on your allocation goals.
What is the holdings overlap between GMMF and VOO?
GMMF and VOO share 0 common holdings with a 0.0% weight overlap. Combined, they hold 521 unique securities.
Which pays a higher dividend, GMMF or VOO?
GMMF yields 3.86% while VOO yields 1.08%, so GMMF currently pays the higher dividend yield.
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