WFSPX vs. VOO
WFSPX (iShares S&P 500 Index Fund Class K) and VOO (Vanguard S&P 500 ETF) are both S&P 500 funds tracking the S&P 500 Index, from BlackRock and Vanguard respectively. Both are passively managed. Over the past 10 years, WFSPX returned 14.85%/yr vs 14.93%/yr for VOO. Their 0.99 correlation means they have historically moved very closely together. Both charge a 0.03% expense ratio.
Performance
WFSPX vs. VOO - Performance Comparison
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Returns By Period
The year-to-date returns for both investments are quite close, with WFSPX having a 8.96% return and VOO slightly higher at 8.98%. Both investments have delivered pretty close results over the past 10 years, with WFSPX having a 14.85% annualized return and VOO not far ahead at 14.93%.
WFSPX
- 1D
- 0.06%
- 1M
- 0.86%
- 6M
- 7.24%
- YTD
- 8.96%
- 1Y
- 17.34%
- 3Y*
- 19.04%
- 5Y*
- 12.49%
- 10Y*
- 14.85%
- ALL TIME*
- 16.24%
VOO
- 1D
- 0.03%
- 1M
- 1.35%
- 6M
- 7.28%
- YTD
- 8.98%
- 1Y
- 17.38%
- 3Y*
- 18.94%
- 5Y*
- 12.57%
- 10Y*
- 14.93%
- ALL TIME*
- 14.72%
Liquidity Comparison
| Position | Avg. Volume Value (2W) | Avg. Volume Value (1M) | Avg. Volume Value (3M) |
|---|---|---|---|
| $3.33B | $3.89B | $5.42B | |
| $0.00 | $0.00 | $0.00 |
WFSPX vs. VOO - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
WFSPX iShares S&P 500 Index Fund Class K | 8.96% | 17.83% | 24.94% | 26.25% | -18.14% | 28.63% | 18.43% | 31.45% | -4.83% | 21.27% |
VOO Vanguard S&P 500 ETF | 8.98% | 17.82% | 24.98% | 26.32% | -18.17% | 28.79% | 18.32% | 31.37% | -4.50% | 21.77% |
Correlation
The correlation between WFSPX and VOO is 1.00 - they have historically moved very closely together. At this level, their price movements offset little of one another.
| Correlation | |
|---|---|
Correlation (1Y) Focuses on recent behavior, but can change the most. | 1.00 |
Correlation (3Y) Balances recent behavior with more history. | 1.00 |
Correlation (5Y) Shows whether the relationship held over a longer period. | 1.00 |
Correlation (10Y) Provides a long-term view across more market conditions. | 0.99 |
Correlation (All Time) Calculated using the full available price history since Sep 9, 2010 | 0.99 |
The correlation between WFSPX and VOO has been stable across timeframes, ranging from 0.99 to 1.00 - a consistent structural relationship.
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Return for Risk
WFSPX vs. VOO — Risk / Return Rank
WFSPX
VOO
WFSPX vs. VOO - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for iShares S&P 500 Index Fund Class K (WFSPX) and Vanguard S&P 500 ETF (VOO). Risk-adjusted metrics are performance indicators that assess an investment's returns in relation to its risk, enabling a more accurate comparison of different investment options.
Values are calculated on a 1-year rolling basis and updated daily. Risk-adjusted metrics are more stable over longer periods — use the period switch above to explore them.
| WFSPX | VOO | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | +0.03 | ||
| Sortino ratioReturn per unit of downside risk | +0.03 | ||
| Omega ratioGain probability vs. loss probability | 1.25 | 1.25 | 0.00 |
| Calmar ratioReturn relative to maximum drawdown | 2.01 | 1.96 | +0.05 |
| Martin ratioReturn relative to average drawdown | 8.71 | 8.43 | +0.28 |
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Drawdowns
WFSPX vs. VOO - Drawdown Comparison
The maximum WFSPX drawdown since its inception was -58.21%, which is greater than VOO's maximum drawdown of -33.99%. Use the drawdown chart below to compare losses from any high point for WFSPX and VOO.
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Drawdown Indicators
| WFSPX | VOO | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -58.21% | -33.99% | -24.22% |
Max Drawdown (1Y)Largest decline over 1 year | -8.90% | -8.90% | 0.00% |
Max Drawdown (3Y)Largest decline over 3 years | -18.74% | -18.69% | -0.05% |
Max Drawdown (5Y)Largest decline over 5 years | -24.51% | -24.52% | +0.01% |
Max Drawdown (10Y)Largest decline over 10 years | -33.74% | -33.99% | +0.25% |
Current DrawdownCurrent decline from peak | -2.44% | -2.43% | -0.01% |
Average DrawdownAverage peak-to-trough decline | -12.73% | -3.67% | -9.06% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 2.05% | 2.07% | -0.02% |
Volatility
WFSPX vs. VOO - Volatility Comparison
The current volatility for iShares S&P 500 Index Fund Class K (WFSPX) is 2.94%, while Vanguard S&P 500 ETF (VOO) has a volatility of 3.22%. This indicates that WFSPX experiences smaller price fluctuations and is considered to be less risky than VOO based on this measure. The chart below showcases a comparison of their rolling one-month volatility.
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Volatility by Period
| WFSPX | VOO | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 2.94% | 3.22% | -0.28% |
Volatility (6M)Calculated over the trailing 6-month period | 9.85% | 9.84% | +0.01% |
Volatility (1Y)Calculated over the trailing 1-year period | 12.66% | 12.64% | +0.02% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 16.96% | 16.91% | +0.05% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 18.01% | 18.01% | 0.00% |
WFSPX vs. VOO - Expense Ratio Comparison
Both WFSPX and VOO have an expense ratio of 0.03%, making them cost-effective options compared to the broader market, where average expense ratios typically range from 0.3% to 0.9%.
Dividends
WFSPX vs. VOO - Dividend Comparison
WFSPX's dividend yield for the trailing twelve months is around 1.67%, more than VOO's 1.08% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
VOO Vanguard S&P 500 ETF | 1.08% | 1.13% | 1.24% | 1.46% | 1.69% | 1.25% | 1.54% | 1.88% | 2.06% | 1.78% | 2.02% | 2.10% |
WFSPX iShares S&P 500 Index Fund Class K | 1.67% | 1.72% | 1.41% | 1.50% | 2.02% | 1.82% | 1.66% | 1.99% | 2.00% | 1.62% | 2.37% | 2.49% |
Frequently Asked Questions
With a correlation of 1.00, WFSPX and VOO move almost identically. Holding both adds very little diversification - you're essentially doubling your position in the same market segment. Choosing one is usually more capital-efficient.
VOO has higher volatility (3.22%) compared to WFSPX (2.94%). In terms of maximum drawdown, WFSPX dropped -58.21% vs VOO's -33.99%.
WFSPX currently has the higher Sharpe Ratio (1.41 vs 1.38), meaning it's delivered slightly more return per unit of risk over the trailing 12 months. However, this ranking shifts over time - use the Risk/Return Score above for a more comprehensive view that combines Sharpe, Sortino, and other measures used by quantitative funds.
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