FMFIX vs. FXNAX

Last updated Jun 24, 2026

FMFIX (RBB Free Market Fixed Income Fund) and FXNAX (Fidelity U.S. Bond Index Fund) are both mutual funds - FMFIX is a Short-Term Bond fund managed by RBB Funds, while FXNAX is a Total Bond Market fund tracking the Bloomberg U.S. Aggregate Bond Index. Over the past 10 years, FMFIX returned 1.24%/yr vs 1.44%/yr for FXNAX. Their correlation of 0.81 suggests significant overlap in exposure. FMFIX charges 0.68%/yr vs 0.03%/yr for FXNAX.

Performance

FMFIX vs. FXNAX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in RBB Free Market Fixed Income Fund (FMFIX) and Fidelity U.S. Bond Index Fund (FXNAX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, FMFIX achieves a 1.00% return, which is significantly higher than FXNAX's 0.11% return. Over the past 10 years, FMFIX has underperformed FXNAX with an annualized return of 1.24%, while FXNAX has yielded a comparatively higher 1.44% annualized return.

FMFIX

• 1D: -0.10%
• 1M: 0.40%
• YTD: 1.00%
• 6M: 1.05%
• 1Y: 3.19%
• 3Y*: 3.32%
• 5Y*: 0.93%
• 10Y*: 1.24%

FXNAX

• 1D: -0.29%
• 1M: 0.61%
• YTD: 0.11%
• 6M: 0.43%
• 1Y: 4.25%
• 3Y*: 3.88%
• 5Y*: -0.05%
• 10Y*: 1.44%

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

FMFIX vs. FXNAX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
FMFIX RBB Free Market Fixed Income Fund	1.00%	4.88%	0.71%	5.43%	-6.52%	-1.06%	3.28%	4.78%	0.65%	1.05%
FXNAX Fidelity U.S. Bond Index Fund	0.11%	7.14%	1.35%	5.82%	-13.55%	-2.10%	7.63%	8.50%	0.04%	3.50%

Correlation

The correlation between FMFIX and FXNAX is 0.80, indicating a strong positive relationship between their price movements. Combining them offers limited diversification - they tend to fall together during downturns.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.80
Correlation (3Y) Calculated over the trailing 3-year period	0.86
Correlation (5Y) Calculated over the trailing 5-year period	0.87
Correlation (10Y) Calculated over the trailing 10-year period	0.82
Correlation (All Time) Calculated using the full available price history since May 4, 2011	0.81

The correlation between FMFIX and FXNAX has been stable across timeframes, ranging from 0.80 to 0.87 - a consistent structural relationship.

Return for Risk

FMFIX vs. FXNAX — Risk / Return Rank

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

FMFIX

FMFIX Risk / Return Rank: 68
FMFIX Sharpe Ratio Rank: 61
FMFIX Sortino Ratio Rank: 71
FMFIX Omega Ratio Rank: 75
FMFIX Calmar Ratio Rank: 72
FMFIX Martin Ratio Rank: 62

FXNAX

FXNAX Risk / Return Rank: 18
FXNAX Sharpe Ratio Rank: 18
FXNAX Sortino Ratio Rank: 20
FXNAX Omega Ratio Rank: 17
FXNAX Calmar Ratio Rank: 20
FXNAX Martin Ratio Rank: 18

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.

FMFIX vs. FXNAX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for RBB Free Market Fixed Income Fund (FMFIX) and Fidelity U.S. Bond Index Fund (FXNAX). 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.

	FMFIX	FXNAX	Difference
Sharpe ratio: Return per unit of total volatility	2.12	1.14	+0.97
Sortino ratio: Return per unit of downside risk	3.20	1.73	+1.48
Omega ratio: Gain probability vs. loss probability	1.45	1.20	+0.25
Calmar ratio: Return relative to maximum drawdown	3.13	1.52	+1.61
Martin ratio: Return relative to average drawdown	11.47	4.36	+7.11

FMFIX vs. FXNAX - Sharpe Ratio Comparison

The current FMFIX Sharpe Ratio is 2.12, which is higher than the FXNAX Sharpe Ratio of 1.14. The chart below compares the historical Sharpe Ratios of FMFIX and FXNAX, 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

FMFIX vs. FXNAX - Drawdown Comparison

The maximum FMFIX drawdown since its inception was -9.35%, smaller than the maximum FXNAX drawdown of -19.51%. Use the drawdown chart below to compare losses from any high point for FMFIX and FXNAX.

Drawdown Indicators

	FMFIX	FXNAX	Difference
Max Drawdown Largest peak-to-trough decline	-9.35%	-19.51%	+10.16%
Max Drawdown (1Y) Largest decline over 1 year	-1.09%	-2.94%	+1.85%
Max Drawdown (3Y) Largest decline over 3 years	-3.72%	-6.16%	+2.44%
Max Drawdown (5Y) Largest decline over 5 years	-9.26%	-18.54%	+9.28%
Max Drawdown (10Y) Largest decline over 10 years	-9.35%	-19.51%	+10.16%
Current Drawdown Current decline from peak	-0.10%	-3.17%	+3.07%
Average Drawdown Average peak-to-trough decline	-1.22%	-3.86%	+2.64%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.30%	1.02%	-0.72%

Volatility

FMFIX vs. FXNAX - Volatility Comparison

The current volatility for RBB Free Market Fixed Income Fund (FMFIX) is 0.51%, while Fidelity U.S. Bond Index Fund (FXNAX) has a volatility of 1.16%. This indicates that FMFIX experiences smaller price fluctuations and is considered to be less risky than FXNAX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FMFIX	FXNAX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.51%	1.16%	-0.65%
Volatility (6M) Calculated over the trailing 6-month period	1.29%	2.90%	-1.61%
Volatility (1Y) Calculated over the trailing 1-year period	1.61%	3.92%	-2.31%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	2.88%	6.08%	-3.20%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	2.44%	5.01%	-2.57%

FMFIX vs. FXNAX - Expense Ratio Comparison

FMFIX has a 0.68% expense ratio, which is higher than FXNAX's 0.03% expense ratio.

Dividends

FMFIX vs. FXNAX - Dividend Comparison

FMFIX's dividend yield for the trailing twelve months is around 3.64%, less than FXNAX's 3.72% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FMFIX RBB Free Market Fixed Income Fund	3.64%	3.49%	0.71%	2.75%	1.35%	0.37%	1.22%	1.44%	2.45%	1.25%	0.58%	0.39%
FXNAX Fidelity U.S. Bond Index Fund	3.72%	3.58%	3.40%	3.15%	1.81%	1.74%	2.92%	2.68%	2.74%	2.57%	2.76%	2.52%

Frequently Asked Questions

Can I hold both FMFIX and FXNAX in my portfolio?

FMFIX and FXNAX have a correlation of 0.80, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, FMFIX or FXNAX?

FXNAX has higher volatility (1.16%) compared to FMFIX (0.51%). In terms of maximum drawdown, FMFIX dropped -9.35% vs FXNAX's -19.51%.

Which has better risk-adjusted returns?

FMFIX currently has the higher Sharpe Ratio (2.12 vs 1.14), 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.