SPAXX vs. FXNAX

Last updated Jun 5, 2026

SPAXX (Fidelity Government Money Market Fund) and FXNAX (Fidelity U.S. Bond Index Fund) are both mutual funds - SPAXX is a Money Market fund actively managed by Fidelity, while FXNAX is a Total Bond Market fund tracking the Bloomberg U.S. Aggregate Bond Index. SPAXX is actively managed, while FXNAX is passively managed. Over the past 5 years, SPAXX returned 1.45%/yr vs 0.02%/yr for FXNAX. At a 0.14 correlation, their price movements are largely independent. SPAXX charges 0.42%/yr vs 0.03%/yr for FXNAX.

Performance

SPAXX vs. FXNAX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Fidelity Government Money Market Fund (SPAXX) 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, SPAXX achieves a 1.37% return, which is significantly higher than FXNAX's 0.21% return.

SPAXX

• 1D: 0.00%
• 1M: 0.28%
• YTD: 1.37%
• 6M: 1.67%
• 1Y: 3.66%
• 3Y*: 2.42%
• 5Y*: 1.45%
• 10Y*: —

FXNAX

• 1D: -0.19%
• 1M: 0.13%
• YTD: 0.21%
• 6M: 0.33%
• 1Y: 4.56%
• 3Y*: 3.95%
• 5Y*: 0.02%
• 10Y*: 1.49%

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

SPAXX vs. FXNAX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021
SPAXX Fidelity Government Money Market Fund	1.37%	3.96%	1.54%	0.41%	0.00%	0.00%
FXNAX Fidelity U.S. Bond Index Fund	0.21%	7.14%	1.35%	5.82%	-13.55%	0.69%

Correlation

The correlation between SPAXX and FXNAX is 0.27, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.27
Correlation (3Y) Calculated over the trailing 3-year period	0.19
Correlation (5Y) Calculated over the trailing 5-year period	0.14
Correlation (All Time) Calculated using the full available price history since May 26, 2021	0.14

The correlation between SPAXX and FXNAX shifts across timeframes, from 0.14 (all time) to 0.27 (1 year), reflecting how their relationship changes across market environments.

Return for Risk

SPAXX vs. FXNAX — Risk / Return Rank

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

FXNAX

FXNAX Risk / Return Rank: 21
FXNAX Sharpe Ratio Rank: 21
FXNAX Sortino Ratio Rank: 22
FXNAX Omega Ratio Rank: 19
FXNAX Calmar Ratio Rank: 23
FXNAX Martin Ratio Rank: 20

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.

SPAXX vs. FXNAX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity Government Money Market Fund (SPAXX) 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.

	SPAXX	FXNAX	Difference
Sharpe ratio: Return per unit of total volatility	3.65	1.31	+2.34
Sortino ratio: Return per unit of downside risk	—	1.98	—
Omega ratio: Gain probability vs. loss probability	—	1.23	—
Calmar ratio: Return relative to maximum drawdown	—	1.76	—
Martin ratio: Return relative to average drawdown	—	5.37	—
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

SPAXX vs. FXNAX - Sharpe Ratio Comparison

The current SPAXX Sharpe Ratio is 3.65, which is higher than the FXNAX Sharpe Ratio of 1.31. The chart below compares the historical Sharpe Ratios of SPAXX 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.

Sharpe Ratios by Period

	SPAXX	FXNAX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	3.65	1.31	+2.34
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	2.13	0.00	+2.13
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	—	0.30	—
Sharpe Ratio (All Time) Calculated using the full available price history	2.13	0.45	+1.67

Drawdowns

SPAXX vs. FXNAX - Drawdown Comparison

The maximum SPAXX drawdown since its inception was 0.00%, smaller than the maximum FXNAX drawdown of -19.51%. Use the drawdown chart below to compare losses from any high point for SPAXX and FXNAX.

Drawdown Indicators

	SPAXX	FXNAX	Difference
Max Drawdown Largest peak-to-trough decline	0.00%	-19.51%	+19.51%
Max Drawdown (1Y) Largest decline over 1 year	0.00%	-2.94%	+2.94%
Max Drawdown (3Y) Largest decline over 3 years	0.00%	-6.16%	+6.16%
Max Drawdown (5Y) Largest decline over 5 years	0.00%	-18.54%	+18.54%
Max Drawdown (10Y) Largest decline over 10 years	—	-19.51%	—
Current Drawdown Current decline from peak	0.00%	-3.07%	+3.07%
Average Drawdown Average peak-to-trough decline	0.00%	-3.87%	+3.87%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.00%	0.97%	-0.97%

Volatility

SPAXX vs. FXNAX - Volatility Comparison

The current volatility for Fidelity Government Money Market Fund (SPAXX) is 0.28%, while Fidelity U.S. Bond Index Fund (FXNAX) has a volatility of 1.37%. This indicates that SPAXX 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

	SPAXX	FXNAX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.28%	1.37%	-1.09%
Volatility (6M) Calculated over the trailing 6-month period	0.72%	2.80%	-2.08%
Volatility (1Y) Calculated over the trailing 1-year period	1.03%	3.96%	-2.93%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	0.69%	6.07%	-5.38%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	0.69%	5.01%	-4.32%

SPAXX vs. FXNAX - Expense Ratio Comparison

SPAXX has a 0.42% expense ratio, which is higher than FXNAX's 0.03% expense ratio.

Dividends

SPAXX vs. FXNAX - Dividend Comparison

SPAXX's dividend yield for the trailing twelve months is around 3.59%, less than FXNAX's 3.71% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FXNAX Fidelity U.S. Bond Index Fund	3.71%	3.58%	3.40%	3.15%	1.81%	1.74%	2.92%	2.68%	2.74%	2.57%	2.76%	2.52%
SPAXX Fidelity Government Money Market Fund	3.59%	3.88%	1.53%	0.41%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%

Frequently Asked Questions

Can I hold both SPAXX and FXNAX in my portfolio?

SPAXX and FXNAX have a correlation of 0.27, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, SPAXX or FXNAX?

FXNAX has higher volatility (1.37%) compared to SPAXX (0.28%). In terms of maximum drawdown, SPAXX dropped 0.00% vs FXNAX's -19.51%.

Which has better risk-adjusted returns?

SPAXX currently has the higher Sharpe Ratio (3.65 vs 1.31), 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.