WFSPX vs. SPXX
WFSPX (iShares S&P 500 Index Fund Class K) and SPXX (Nuveen S&P 500 Dynamic Overwrite Fund) are both S&P 500 funds. WFSPX is passively managed, while SPXX is actively managed. Over the past 10 years, WFSPX returned 15.68%/yr vs 10.31%/yr for SPXX. A 0.71 correlation means they provide meaningful diversification when combined. WFSPX charges 0.03%/yr vs 0.89%/yr for SPXX.
Performance
WFSPX vs. SPXX - Performance Comparison
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Returns By Period
In the year-to-date period, WFSPX achieves a 9.77% return, which is significantly higher than SPXX's 3.44% return. Over the past 10 years, WFSPX has outperformed SPXX with an annualized return of 15.68%, while SPXX has yielded a comparatively lower 10.31% annualized return.
WFSPX
- 1D
- -0.36%
- 1M
- 0.10%
- YTD
- 9.77%
- 6M
- 8.77%
- 1Y
- 25.45%
- 3Y*
- 21.35%
- 5Y*
- 13.57%
- 10Y*
- 15.68%
SPXX
- 1D
- -1.05%
- 1M
- 1.41%
- YTD
- 3.44%
- 6M
- 3.84%
- 1Y
- 13.31%
- 3Y*
- 13.85%
- 5Y*
- 7.18%
- 10Y*
- 10.31%
WFSPX vs. SPXX - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
WFSPX iShares S&P 500 Index Fund Class K | 9.77% | 17.83% | 24.94% | 26.25% | -18.14% | 28.63% | 18.43% | 31.45% | -4.83% | 21.27% |
SPXX Nuveen S&P 500 Dynamic Overwrite Fund | 3.44% | 9.78% | 27.10% | 0.85% | -6.92% | 29.03% | -0.37% | 25.36% | -13.42% | 27.92% |
Correlation
The correlation between WFSPX and SPXX is 0.77, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.
| Correlation | |
|---|---|
Correlation (1Y) Calculated over the trailing 1-year period | 0.77 |
Correlation (3Y) Calculated over the trailing 3-year period | 0.78 |
Correlation (5Y) Calculated over the trailing 5-year period | 0.78 |
Correlation (10Y) Calculated over the trailing 10-year period | 0.71 |
Correlation (All Time) Calculated using the full available price history since Nov 23, 2005 | 0.71 |
The correlation between WFSPX and SPXX has been stable across timeframes, ranging from 0.71 to 0.78 - a consistent structural relationship.
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Return for Risk
WFSPX vs. SPXX — Risk / Return Rank
WFSPX
SPXX
WFSPX vs. SPXX - 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 Nuveen S&P 500 Dynamic Overwrite Fund (SPXX). 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 | SPXX | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | +1.07 | ||
| Sortino ratioReturn per unit of downside risk | +1.32 | ||
| Omega ratioGain probability vs. loss probability | 1.39 | 1.19 | +0.20 |
| Calmar ratioReturn relative to maximum drawdown | 3.01 | 1.13 | +1.88 |
| Martin ratioReturn relative to average drawdown | 13.58 | 3.83 | +9.76 |
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Drawdowns
WFSPX vs. SPXX - Drawdown Comparison
The maximum WFSPX drawdown since its inception was -58.21%, which is greater than SPXX's maximum drawdown of -52.39%. Use the drawdown chart below to compare losses from any high point for WFSPX and SPXX.
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Drawdown Indicators
| WFSPX | SPXX | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -58.21% | -52.39% | -5.82% |
Max Drawdown (1Y)Largest decline over 1 year | -8.90% | -11.86% | +2.96% |
Max Drawdown (3Y)Largest decline over 3 years | -18.74% | -17.65% | -1.09% |
Max Drawdown (5Y)Largest decline over 5 years | -24.51% | -18.09% | -6.42% |
Max Drawdown (10Y)Largest decline over 10 years | -33.74% | -43.99% | +10.25% |
Current DrawdownCurrent decline from peak | -1.72% | -1.43% | -0.29% |
Average DrawdownAverage peak-to-trough decline | -12.76% | -7.45% | -5.31% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 1.97% | 3.49% | -1.52% |
Volatility
WFSPX vs. SPXX - Volatility Comparison
iShares S&P 500 Index Fund Class K (WFSPX) has a higher volatility of 4.67% compared to Nuveen S&P 500 Dynamic Overwrite Fund (SPXX) at 4.41%. This indicates that WFSPX's price experiences larger fluctuations and is considered to be riskier than SPXX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.
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Volatility by Period
| WFSPX | SPXX | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 4.67% | 4.41% | +0.26% |
Volatility (6M)Calculated over the trailing 6-month period | 9.83% | 9.55% | +0.28% |
Volatility (1Y)Calculated over the trailing 1-year period | 12.49% | 12.45% | +0.04% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 16.97% | 15.71% | +1.26% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 18.07% | 18.43% | -0.36% |
WFSPX vs. SPXX - Expense Ratio Comparison
WFSPX has a 0.03% expense ratio, which is lower than SPXX's 0.89% expense ratio.
Dividends
WFSPX vs. SPXX - Dividend Comparison
WFSPX's dividend yield for the trailing twelve months is around 1.59%, less than SPXX's 8.02% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
SPXX Nuveen S&P 500 Dynamic Overwrite Fund | 8.02% | 7.48% | 6.87% | 7.82% | 7.30% | 5.27% | 6.56% | 6.44% | 7.98% | 5.69% | 5.14% | 7.75% |
WFSPX iShares S&P 500 Index Fund Class K | 1.59% | 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
WFSPX and SPXX have a correlation of 0.77, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.
WFSPX has higher volatility (4.67%) compared to SPXX (4.41%). In terms of maximum drawdown, WFSPX dropped -58.21% vs SPXX's -52.39%.
WFSPX currently has the higher Sharpe Ratio (2.15 vs 1.08), 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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