RYSOX vs. FDFIX

Last updated Jun 24, 2026

RYSOX (Rydex S&P 500 Fund) and FDFIX (Fidelity Flex 500 Index Fund) are both mutual funds - RYSOX is a S&P 500 fund tracking the S&P 500 Index, while FDFIX is a Large Cap Blend Equities fund tracking the Fidelity U.S. Large Cap Index. Both are passively managed. Over the past 5 years, RYSOX returned 11.75%/yr vs 13.53%/yr for FDFIX. With a 1.00 correlation, they move nearly in lockstep. RYSOX charges 1.56%/yr vs 0.00%/yr for FDFIX.

Performance

RYSOX vs. FDFIX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Rydex S&P 500 Fund (RYSOX) and Fidelity Flex 500 Index Fund (FDFIX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, RYSOX achieves a 8.94% return, which is significantly lower than FDFIX's 9.64% return.

RYSOX

• 1D: -0.37%
• 1M: -0.02%
• YTD: 8.94%
• 6M: 7.91%
• 1Y: 23.49%
• 3Y*: 19.41%
• 5Y*: 11.75%
• 10Y*: 13.84%

FDFIX

• 1D: -0.38%
• 1M: 0.31%
• YTD: 9.64%
• 6M: 8.63%
• 1Y: 25.08%
• 3Y*: 21.26%
• 5Y*: 13.53%
• 10Y*: —

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

RYSOX vs. FDFIX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
RYSOX Rydex S&P 500 Fund	8.94%	15.93%	22.98%	24.15%	-19.47%	26.68%	16.25%	29.15%	-6.01%	13.12%
FDFIX Fidelity Flex 500 Index Fund	9.64%	17.59%	25.06%	26.27%	-18.10%	28.69%	18.46%	31.47%	-4.45%	14.41%

Correlation

The correlation between RYSOX and FDFIX is 1.00 - these two move nearly in lockstep. At this level, holding both provides almost no diversification benefit. If you already own one, adding the other does little to reduce portfolio risk.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	1.00
Correlation (3Y) Calculated over the trailing 3-year period	0.99
Correlation (5Y) Calculated over the trailing 5-year period	1.00
Correlation (All Time) Calculated using the full available price history since Mar 9, 2017	1.00

The correlation between RYSOX and FDFIX has been stable across timeframes, ranging from 0.99 to 1.00 - a consistent structural relationship.

Return for Risk

RYSOX vs. FDFIX — Risk / Return Rank

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

RYSOX

RYSOX Risk / Return Rank: 55
RYSOX Sharpe Ratio Rank: 53
RYSOX Sortino Ratio Rank: 49
RYSOX Omega Ratio Rank: 51
RYSOX Calmar Ratio Rank: 55
RYSOX Martin Ratio Rank: 66

FDFIX

FDFIX Risk / Return Rank: 61
FDFIX Sharpe Ratio Rank: 60
FDFIX Sortino Ratio Rank: 54
FDFIX Omega Ratio Rank: 56
FDFIX Calmar Ratio Rank: 65
FDFIX Martin Ratio Rank: 73

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.

RYSOX vs. FDFIX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Rydex S&P 500 Fund (RYSOX) and Fidelity Flex 500 Index Fund (FDFIX). 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.

	RYSOX	FDFIX	Difference
Sharpe ratio: Return per unit of total volatility	1.99	2.10	-0.11
Sortino ratio: Return per unit of downside risk	2.71	2.83	-0.13
Omega ratio: Gain probability vs. loss probability	1.36	1.38	-0.02
Calmar ratio: Return relative to maximum drawdown	2.73	2.95	-0.21
Martin ratio: Return relative to average drawdown	12.10	12.98	-0.88

RYSOX vs. FDFIX - Sharpe Ratio Comparison

The current RYSOX Sharpe Ratio is 1.99, which is comparable to the FDFIX Sharpe Ratio of 2.10. The chart below compares the historical Sharpe Ratios of RYSOX and FDFIX, 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

RYSOX vs. FDFIX - Drawdown Comparison

The maximum RYSOX drawdown since its inception was -55.24%, which is greater than FDFIX's maximum drawdown of -33.77%. Use the drawdown chart below to compare losses from any high point for RYSOX and FDFIX.

Drawdown Indicators

	RYSOX	FDFIX	Difference
Max Drawdown Largest peak-to-trough decline	-55.24%	-33.77%	-21.47%
Max Drawdown (1Y) Largest decline over 1 year	-9.06%	-8.99%	-0.07%
Max Drawdown (3Y) Largest decline over 3 years	-18.94%	-18.76%	-0.18%
Max Drawdown (5Y) Largest decline over 5 years	-25.45%	-24.51%	-0.94%
Max Drawdown (10Y) Largest decline over 10 years	-34.05%	—	—
Current Drawdown Current decline from peak	-1.80%	-1.70%	-0.10%
Average Drawdown Average peak-to-trough decline	-8.25%	-4.56%	-3.69%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.04%	2.03%	+0.01%

Volatility

RYSOX vs. FDFIX - Volatility Comparison

Rydex S&P 500 Fund (RYSOX) and Fidelity Flex 500 Index Fund (FDFIX) have volatilities of 4.67% and 4.81%, respectively, indicating that both stocks experience similar levels of price fluctuations. This suggests that the risk associated with both stocks, as measured by volatility, is nearly the same. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	RYSOX	FDFIX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.67%	4.81%	-0.14%
Volatility (6M) Calculated over the trailing 6-month period	9.81%	10.00%	-0.19%
Volatility (1Y) Calculated over the trailing 1-year period	12.48%	12.64%	-0.16%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	17.00%	17.05%	-0.05%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	18.14%	18.59%	-0.45%

RYSOX vs. FDFIX - Expense Ratio Comparison

RYSOX has a 1.56% expense ratio, which is higher than FDFIX's 0.00% expense ratio.

Dividends

RYSOX vs. FDFIX - Dividend Comparison

RYSOX's dividend yield for the trailing twelve months is around 2.43%, more than FDFIX's 1.04% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FDFIX Fidelity Flex 500 Index Fund	1.04%	1.11%	1.26%	1.48%	1.70%	1.27%	1.52%	1.78%	2.16%	0.50%	0.00%	0.00%
RYSOX Rydex S&P 500 Fund	2.43%	2.65%	1.08%	0.60%	1.17%	1.25%	13.42%	0.93%	1.69%	4.56%	0.84%	4.01%

Frequently Asked Questions

Can I hold both RYSOX and FDFIX in my portfolio?

With a correlation of 1.00, RYSOX and FDFIX 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.

Which is riskier, RYSOX or FDFIX?

FDFIX has higher volatility (4.81%) compared to RYSOX (4.67%). In terms of maximum drawdown, RYSOX dropped -55.24% vs FDFIX's -33.77%.

Which has better risk-adjusted returns?

FDFIX currently has the higher Sharpe Ratio (2.10 vs 1.99), 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.