SPFIX vs. SPXX

Last updated Jun 24, 2026

SPFIX (Shelton Capital Management S&P 500 Index Fund) and SPXX (Nuveen S&P 500 Dynamic Overwrite Fund) are both S&P 500 funds. SPFIX is passively managed, while SPXX is actively managed. Over the past 10 years, SPFIX returned 17.83%/yr vs 10.31%/yr for SPXX. A 0.71 correlation means they provide meaningful diversification when combined. SPFIX charges 0.43%/yr vs 0.89%/yr for SPXX.

Performance

SPFIX vs. SPXX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Shelton Capital Management S&P 500 Index Fund (SPFIX) and Nuveen S&P 500 Dynamic Overwrite Fund (SPXX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, SPFIX achieves a 9.49% return, which is significantly higher than SPXX's 3.44% return. Over the past 10 years, SPFIX has outperformed SPXX with an annualized return of 17.83%, while SPXX has yielded a comparatively lower 10.31% annualized return.

SPFIX

• 1D: -0.37%
• 1M: 0.07%
• YTD: 9.49%
• 6M: 8.49%
• 1Y: 25.03%
• 3Y*: 26.40%
• 5Y*: 16.23%
• 10Y*: 17.83%

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%

*Multi-year figures are annualized to reflect compound growth (CAGR)

SPFIX vs. SPXX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
SPFIX Shelton Capital Management S&P 500 Index Fund	9.49%	17.23%	42.83%	25.48%	-18.22%	27.99%	17.41%	41.64%	-4.68%	21.55%
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 SPFIX 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	0.79
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 SPFIX and SPXX has been stable across timeframes, ranging from 0.71 to 0.79 - a consistent structural relationship.

Return for Risk

SPFIX vs. SPXX — Risk / Return Rank

Compare risk-adjusted metric ranks to identify better-performing investments over the past 12 months.

SPFIX

SPFIX Risk / Return Rank: 63
SPFIX Sharpe Ratio Rank: 61
SPFIX Sortino Ratio Rank: 56
SPFIX Omega Ratio Rank: 58
SPFIX Calmar Ratio Rank: 65
SPFIX Martin Ratio Rank: 75

SPXX

SPXX Risk / Return Rank: 15
SPXX Sharpe Ratio Rank: 16
SPXX Sortino Ratio Rank: 16
SPXX Omega Ratio Rank: 15
SPXX Calmar Ratio Rank: 13
SPXX Martin Ratio Rank: 15

The rank (0–100) shows how this investment's returns compare to the risk taken. Higher = better. Based on the past 12 months of data, combining Sharpe, Sortino, and other metrics used by quantitative funds and institutional investors.

SPFIX vs. SPXX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Shelton Capital Management S&P 500 Index Fund (SPFIX) 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.

	SPFIX	SPXX	Difference
Sharpe ratio: Return per unit of total volatility	2.12	1.08	+1.04
Sortino ratio: Return per unit of downside risk	2.87	1.59	+1.28
Omega ratio: Gain probability vs. loss probability	1.38	1.19	+0.20
Calmar ratio: Return relative to maximum drawdown	2.96	1.13	+1.83
Martin ratio: Return relative to average drawdown	13.32	3.83	+9.50

SPFIX vs. SPXX - Sharpe Ratio Comparison

The current SPFIX Sharpe Ratio is 2.12, which is higher than the SPXX Sharpe Ratio of 1.08. The chart below compares the historical Sharpe Ratios of SPFIX and SPXX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Drawdowns

SPFIX vs. SPXX - Drawdown Comparison

The maximum SPFIX drawdown since its inception was -54.81%, roughly equal to the maximum SPXX drawdown of -52.39%. Use the drawdown chart below to compare losses from any high point for SPFIX and SPXX.

Drawdown Indicators

	SPFIX	SPXX	Difference
Max Drawdown Largest peak-to-trough decline	-54.81%	-52.39%	-2.42%
Max Drawdown (1Y) Largest decline over 1 year	-8.90%	-11.86%	+2.96%
Max Drawdown (3Y) Largest decline over 3 years	-18.94%	-17.65%	-1.29%
Max Drawdown (5Y) Largest decline over 5 years	-24.69%	-18.09%	-6.60%
Max Drawdown (10Y) Largest decline over 10 years	-33.83%	-43.99%	+10.16%
Current Drawdown Current decline from peak	-1.73%	-1.43%	-0.30%
Average Drawdown Average peak-to-trough decline	-8.94%	-7.45%	-1.49%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.97%	3.49%	-1.52%

Volatility

SPFIX vs. SPXX - Volatility Comparison

Shelton Capital Management S&P 500 Index Fund (SPFIX) has a higher volatility of 4.66% compared to Nuveen S&P 500 Dynamic Overwrite Fund (SPXX) at 4.41%. This indicates that SPFIX'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.

Volatility by Period

	SPFIX	SPXX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.66%	4.41%	+0.25%
Volatility (6M) Calculated over the trailing 6-month period	9.80%	9.55%	+0.25%
Volatility (1Y) Calculated over the trailing 1-year period	12.45%	12.45%	0.00%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	18.31%	15.71%	+2.60%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.92%	18.43%	+0.49%

SPFIX vs. SPXX - Expense Ratio Comparison

SPFIX has a 0.43% expense ratio, which is lower than SPXX's 0.89% expense ratio.

Dividends

SPFIX vs. SPXX - Dividend Comparison

SPFIX's dividend yield for the trailing twelve months is around 3.32%, less than SPXX's 8.02% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
SPFIX Shelton Capital Management S&P 500 Index Fund	3.32%	3.45%	27.20%	8.08%	5.07%	5.43%	8.06%	16.60%	2.49%	3.01%	2.92%	4.35%
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%

Frequently Asked Questions

Can I hold both SPFIX and SPXX in my portfolio?

SPFIX 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.

Which is riskier, SPFIX or SPXX?

SPFIX has higher volatility (4.66%) compared to SPXX (4.41%). In terms of maximum drawdown, SPFIX dropped -54.81% vs SPXX's -52.39%.

Which has better risk-adjusted returns?

SPFIX currently has the higher Sharpe Ratio (2.12 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.