SEIS vs VOO
SEI Select Small Cap ETF vs Vanguard S&P 500 ETF
Which is better, SEIS or VOO?
Small Cap Blend against Large Cap Blend.
VOO has a lower expense ratio. VOO led over 1Y and the full window. SEIS is less concentrated, with 10.7% of the fund in its ten largest positions against 36.4%.
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 | SEIS | VOO |
|---|---|---|
| Expense Ratio | 0.55% | 0.03%Best |
| AUM | $602M | $997.4B |
| Dividend Yield | 0.34% | 1.08% |
| Holdings | 373 | 509 |
| YTD Return | +15.99%Best | +13.81% |
| 1Y Return | +19.20% | +21.53%Best |
| 3Y Return (annualized) | - | +21.46% |
| 5Y Return (annualized) | - | +12.87% |
| Volatility (annualized) | 18.4% | 12.8%Best |
| Max Drawdown | -25.7% | -18.7%Best |
| $10,000 over 1.9 years | $13,069 | $13,717Best |
| Top 10 Weight | 10.7%Best | 36.4% |
| Fund Family | SEI EXCHANGE TRADED FUNDS | Vanguard (US) |
| Category | Equity | Equity |
| Style | Small Cap Blend | Large Cap Blend |
| Inception | Oct 8, 2024 | Sep 7, 2010 |
Volatility and max drawdown, and the $10,000 over 1.9 years row, are measured over the window both funds cover: Oct 10, 2024 to Sep 3, 2026 (1.9 years).
SEIS vs VOO 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 1.9 years both funds cover.
SEIS vs VOO Performance
SEI Select Small Cap ETF (SEIS) is an ETF from SEI EXCHANGE TRADED FUNDS and Vanguard S&P 500 ETF (VOO) is an ETF from Vanguard (US). Over the past year SEIS returned +19.20% while VOO returned +21.53%. Year to date, SEIS is up 15.99% versus a gain of 13.81% for VOO.
Past performance does not guarantee future results.
Risk: Volatility and Drawdowns
SEIS has been the more volatile fund, with annualized monthly volatility of 18.4% compared with 12.8% for VOO. 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 -25.7% for SEIS and -18.7% for VOO. Drawdown depth is what each fund did in the worst stretch of the window measured above.
The two funds' monthly returns correlate at 0.79. They usually move together, but the gap leaves some room for diversification.
Fees and Cost Over Time
SEIS charges 0.55% per year while VOO charges 0.03%. On a $10,000 position that is $55 vs $3 annually, a gap of $52 per year that compounds over a long holding period. On income, SEIS currently yields 0.34% against 1.08% for VOO.
Holdings Overlap
3.0% of SEIS's money is in holdings VOO also owns. 0.6% of VOO's money is in holdings SEIS also owns.
SEIS and VOO share little of their money.
The two holdings books were reported 49 days apart, SEIS as of Aug 18, 2026 and VOO as of Jun 30, 2026, so some of the difference between them is the time between the two reports rather than the funds.
10 positions in common, counted across the 369 positions we hold weights for in SEIS and 505 in VOO, against full books of 373 and 509.
What only one of them owns
Our book lists 487 positions for VOO that do not appear in our book for SEIS (98.9% of the fund), and 341 for SEIS that do not appear in VOO (90.8%).
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 SEIS | Weight in VOO | Difference |
|---|---|---|---|
| KEYSKeysight Technologies Inc. | 0.69% | 0.09% | 0.60% |
| AXONAxon Enterprise Inc | 0.47% | 0.07% | 0.40% |
| FTNTFortinet Inc | 0.36% | 0.15% | 0.21% |
| MPWRMonolithic Power Systems Inc | 0.37% | 0.11% | 0.26% |
| TYLTyler Technologies Inc | 0.26% | 0.02% | 0.24% |
| CHDChurch & Dwight Co. Inc. | 0.24% | 0.04% | 0.20% |
| ROLRollins Inc. | 0.22% | 0.02% | 0.20% |
| FICOFair Isaac Corproation | 0.17% | 0.04% | 0.13% |
| CPRTCopart Inc | 0.10% | 0.04% | 0.06% |
| CSGPCostar Group Inc. | 0.11% | 0.02% | 0.09% |
You are not choosing between two funds in isolation.
Whichever of SEIS and VOO you pick has to sit alongside everything else you own. Add the rest and see what the combination actually holds.
Free for up to 10 holdings. No account needed.
Frequently Asked Questions
Which is cheaper, SEIS or VOO?
SEIS has an expense ratio of 0.55% while VOO charges 0.03%. VOO is the cheaper option, by $52 a year on a $10,000 investment.
Which performed better, SEIS or VOO?
Over the past year SEIS returned +19.20% vs +21.53% for VOO, so VOO leads on 1-year performance. Over the longest common window we track (2 years), SEIS annualized +15.13% vs +18.10% for VOO. Past performance does not guarantee future results. This is information, not a recommendation.
Which is riskier, SEIS or VOO?
SEIS has been the more volatile fund at 18.4% annualized versus 12.8% for VOO. Worst drawdown: SEIS -25.7% vs VOO -18.7%.
Should I hold both SEIS and VOO?
SEIS and VOO have a monthly-return correlation of 0.79, so their returns are far enough apart for the mix to behave differently from either one alone. This is information, not a recommendation.
What is the holdings overlap between SEIS and VOO?
3.0% of SEIS's money is in holdings VOO also owns. 0.6% of VOO's is in holdings SEIS also owns. They hold 10 positions in common, counted across the 369 positions we hold weights for in SEIS and 505 in VOO.
Which pays a higher dividend, SEIS or VOO?
SEIS yields 0.34% while VOO yields 1.08%, so VOO currently pays the higher dividend yield.
Is VOO better than SEIS?
VOO has a lower expense ratio. VOO led over 1Y and the full window. SEIS is less concentrated, with 10.7% of the fund in its ten largest positions against 36.4%. Which one suits a particular account depends on what it is for. This is information, not a recommendation.