SOPIX vs. FXAIX

Last updated Jun 23, 2026

SOPIX (ProFunds Short NASDAQ-100 Fund) and FXAIX (Fidelity 500 Index Fund) are both mutual funds - SOPIX is a Inverse Equities fund managed by ProFunds, while FXAIX is a S&P 500 fund tracking the S&P 500 Index. Over the past 10 years, SOPIX returned -20.89%/yr vs 15.58%/yr for FXAIX. At a correlation of -0.90, they often move in opposite directions. SOPIX charges 1.78%/yr vs 0.02%/yr for FXAIX.

Performance

SOPIX vs. FXAIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in ProFunds Short NASDAQ-100 Fund (SOPIX) and Fidelity 500 Index Fund (FXAIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, SOPIX achieves a -16.61% return, which is significantly lower than FXAIX's 10.19% return. Over the past 10 years, SOPIX has underperformed FXAIX with an annualized return of -20.89%, while FXAIX has yielded a comparatively higher 15.58% annualized return.

SOPIX

• 1D: -2.47%
• 1M: -3.30%
• YTD: -16.61%
• 6M: -15.82%
• 1Y: -27.00%
• 3Y*: -20.90%
• 5Y*: -16.29%
• 10Y*: -20.89%

FXAIX

• 1D: 1.09%
• 1M: 0.47%
• YTD: 10.19%
• 6M: 9.68%
• 1Y: 27.18%
• 3Y*: 20.98%
• 5Y*: 14.10%
• 10Y*: 15.58%

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

SOPIX vs. FXAIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
SOPIX ProFunds Short NASDAQ-100 Fund	-16.61%	-15.80%	-23.82%	-31.85%	34.73%	-25.69%	-42.92%	-28.29%	-3.07%	-25.24%
FXAIX Fidelity 500 Index Fund	10.19%	17.84%	25.01%	26.29%	-18.14%	28.71%	18.42%	31.48%	-4.43%	21.82%

Correlation

The correlation between SOPIX and FXAIX is -0.94, meaning they tend to move in opposite directions. This is especially valuable for risk management - when one declines, the other has historically tended to hold steady or rise.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	-0.94
Correlation (3Y) Calculated over the trailing 3-year period	-0.93
Correlation (5Y) Calculated over the trailing 5-year period	-0.93
Correlation (10Y) Calculated over the trailing 10-year period	-0.90
Correlation (All Time) Calculated using the full available price history since May 4, 2011	-0.90

The correlation between SOPIX and FXAIX has been stable across timeframes, ranging from -0.94 to -0.90 - a consistent structural relationship.

Return for Risk

SOPIX vs. FXAIX — Risk / Return Rank

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

SOPIX

SOPIX Risk / Return Rank: 0
SOPIX Sharpe Ratio Rank: 0
SOPIX Sortino Ratio Rank: 0
SOPIX Omega Ratio Rank: 0
SOPIX Calmar Ratio Rank: 0
SOPIX Martin Ratio Rank: 0

FXAIX

FXAIX Risk / Return Rank: 66
FXAIX Sharpe Ratio Rank: 64
FXAIX Sortino Ratio Rank: 59
FXAIX Omega Ratio Rank: 61
FXAIX Calmar Ratio Rank: 68
FXAIX Martin Ratio Rank: 79

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.

SOPIX vs. FXAIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for ProFunds Short NASDAQ-100 Fund (SOPIX) and Fidelity 500 Index Fund (FXAIX). 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.

	SOPIX	FXAIX	Difference
Sharpe ratio: Return per unit of total volatility	-1.52	2.17	-3.69
Sortino ratio: Return per unit of downside risk	-2.28	2.93	-5.21
Omega ratio: Gain probability vs. loss probability	0.76	1.39	-0.64
Calmar ratio: Return relative to maximum drawdown	-0.98	3.04	-4.02
Martin ratio: Return relative to average drawdown	-1.96	13.75	-15.70

SOPIX vs. FXAIX - Sharpe Ratio Comparison

The current SOPIX Sharpe Ratio is -1.52, which is lower than the FXAIX Sharpe Ratio of 2.17. The chart below compares the historical Sharpe Ratios of SOPIX and FXAIX, 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

SOPIX vs. FXAIX - Drawdown Comparison

The maximum SOPIX drawdown since its inception was -99.07%, which is greater than FXAIX's maximum drawdown of -33.79%. Use the drawdown chart below to compare losses from any high point for SOPIX and FXAIX.

Drawdown Indicators

	SOPIX	FXAIX	Difference
Max Drawdown Largest peak-to-trough decline	-99.07%	-33.79%	-65.28%
Max Drawdown (1Y) Largest decline over 1 year	-26.57%	-8.89%	-17.68%
Max Drawdown (3Y) Largest decline over 3 years	-54.87%	-18.76%	-36.11%
Max Drawdown (5Y) Largest decline over 5 years	-65.00%	-24.50%	-40.50%
Max Drawdown (10Y) Largest decline over 10 years	-90.86%	-33.79%	-57.07%
Current Drawdown Current decline from peak	-99.06%	-1.36%	-97.70%
Average Drawdown Average peak-to-trough decline	-76.17%	-3.79%	-72.38%
Ulcer Index Depth and duration of drawdowns from previous peaks	13.63%	1.96%	+11.67%

Volatility

SOPIX vs. FXAIX - Volatility Comparison

ProFunds Short NASDAQ-100 Fund (SOPIX) has a higher volatility of 8.39% compared to Fidelity 500 Index Fund (FXAIX) at 4.77%. This indicates that SOPIX's price experiences larger fluctuations and is considered to be riskier than FXAIX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	SOPIX	FXAIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	8.39%	4.77%	+3.62%
Volatility (6M) Calculated over the trailing 6-month period	14.28%	9.91%	+4.37%
Volatility (1Y) Calculated over the trailing 1-year period	17.63%	12.47%	+5.16%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	23.61%	17.01%	+6.60%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	22.61%	18.11%	+4.50%

SOPIX vs. FXAIX - Expense Ratio Comparison

SOPIX has a 1.78% expense ratio, which is higher than FXAIX's 0.02% expense ratio.

Dividends

SOPIX vs. FXAIX - Dividend Comparison

SOPIX's dividend yield for the trailing twelve months is around 2.57%, more than FXAIX's 1.04% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FXAIX Fidelity 500 Index Fund	1.04%	1.11%	1.25%	1.45%	1.69%	1.22%	1.60%	2.06%	2.72%	1.97%	2.52%	2.83%
SOPIX ProFunds Short NASDAQ-100 Fund	2.57%	2.14%	0.00%	6.71%	0.00%	0.00%	0.00%	0.29%	0.00%	0.00%	0.00%	0.00%

Frequently Asked Questions

Can I hold both SOPIX and FXAIX in my portfolio?

SOPIX and FXAIX have a correlation of -0.94, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, SOPIX or FXAIX?

SOPIX has higher volatility (8.39%) compared to FXAIX (4.77%). In terms of maximum drawdown, SOPIX dropped -99.07% vs FXAIX's -33.79%.

Which has better risk-adjusted returns?

FXAIX currently has the higher Sharpe Ratio (2.17 vs -1.52), 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.