FXNAX vs. FNBGX

Last updated Jun 24, 2026

FXNAX (Fidelity U.S. Bond Index Fund) and FNBGX (Fidelity Long-Term Treasury Bond Index Fund) are both mutual funds - FXNAX is a Total Bond Market fund tracking the Bloomberg U.S. Aggregate Bond Index, while FNBGX is a Government Bonds fund managed by Fidelity. Over the past 5 years, FXNAX returned -0.05%/yr vs -5.72%/yr for FNBGX. Their correlation of 0.91 suggests significant overlap in exposure. FXNAX charges 0.03%/yr vs 0.03%/yr for FNBGX.

Performance

FXNAX vs. FNBGX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Fidelity U.S. Bond Index Fund (FXNAX) and Fidelity Long-Term Treasury Bond Index Fund (FNBGX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, FXNAX achieves a 0.11% return, which is significantly lower than FNBGX's 0.13% return.

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%

FNBGX

• 1D: -0.65%
• 1M: 1.91%
• YTD: 0.13%
• 6M: 0.25%
• 1Y: 4.01%
• 3Y*: -0.79%
• 5Y*: -5.72%
• 10Y*: —

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

FXNAX vs. FNBGX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
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%	0.38%
FNBGX Fidelity Long-Term Treasury Bond Index Fund	0.13%	5.30%	-6.18%	3.20%	-29.89%	-5.17%	17.58%	14.24%	-1.62%	1.86%

Correlation

The correlation between FXNAX and FNBGX is 0.91, 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	0.91
Correlation (3Y) Calculated over the trailing 3-year period	0.93
Correlation (5Y) Calculated over the trailing 5-year period	0.93
Correlation (All Time) Calculated using the full available price history since Oct 19, 2017	0.91

The correlation between FXNAX and FNBGX has been stable across timeframes, ranging from 0.91 to 0.93 - a consistent structural relationship.

Return for Risk

FXNAX vs. FNBGX — Risk / Return Rank

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

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

FNBGX

FNBGX Risk / Return Rank: 6
FNBGX Sharpe Ratio Rank: 7
FNBGX Sortino Ratio Rank: 7
FNBGX Omega Ratio Rank: 6
FNBGX Calmar Ratio Rank: 7
FNBGX Martin Ratio Rank: 6

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.

FXNAX vs. FNBGX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Fidelity U.S. Bond Index Fund (FXNAX) and Fidelity Long-Term Treasury Bond Index Fund (FNBGX). 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.

	FXNAX	FNBGX	Difference
Sharpe ratio: Return per unit of total volatility	1.14	0.50	+0.64
Sortino ratio: Return per unit of downside risk	1.73	0.78	+0.95
Omega ratio: Gain probability vs. loss probability	1.20	1.09	+0.11
Calmar ratio: Return relative to maximum drawdown	1.52	0.60	+0.92
Martin ratio: Return relative to average drawdown	4.36	1.51	+2.86

FXNAX vs. FNBGX - Sharpe Ratio Comparison

The current FXNAX Sharpe Ratio is 1.14, which is higher than the FNBGX Sharpe Ratio of 0.50. The chart below compares the historical Sharpe Ratios of FXNAX and FNBGX, 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

FXNAX vs. FNBGX - Drawdown Comparison

The maximum FXNAX drawdown since its inception was -19.51%, smaller than the maximum FNBGX drawdown of -46.86%. Use the drawdown chart below to compare losses from any high point for FXNAX and FNBGX.

Drawdown Indicators

	FXNAX	FNBGX	Difference
Max Drawdown Largest peak-to-trough decline	-19.51%	-46.86%	+27.35%
Max Drawdown (1Y) Largest decline over 1 year	-2.94%	-7.28%	+4.34%
Max Drawdown (3Y) Largest decline over 3 years	-6.16%	-17.66%	+11.50%
Max Drawdown (5Y) Largest decline over 5 years	-18.54%	-41.54%	+23.00%
Max Drawdown (10Y) Largest decline over 10 years	-19.51%	—	—
Current Drawdown Current decline from peak	-3.17%	-37.17%	+34.00%
Average Drawdown Average peak-to-trough decline	-3.86%	-21.73%	+17.87%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.02%	2.89%	-1.87%

Volatility

FXNAX vs. FNBGX - Volatility Comparison

The current volatility for Fidelity U.S. Bond Index Fund (FXNAX) is 1.16%, while Fidelity Long-Term Treasury Bond Index Fund (FNBGX) has a volatility of 2.09%. This indicates that FXNAX experiences smaller price fluctuations and is considered to be less risky than FNBGX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	FXNAX	FNBGX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.16%	2.09%	-0.93%
Volatility (6M) Calculated over the trailing 6-month period	2.90%	6.16%	-3.26%
Volatility (1Y) Calculated over the trailing 1-year period	3.92%	8.71%	-4.79%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	6.08%	14.54%	-8.46%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	5.01%	14.17%	-9.16%

FXNAX vs. FNBGX - Expense Ratio Comparison

FXNAX has a 0.03% expense ratio, which is lower than FNBGX's 0.03% expense ratio. Despite the difference, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

Dividends

FXNAX vs. FNBGX - Dividend Comparison

FXNAX's dividend yield for the trailing twelve months is around 3.72%, less than FNBGX's 3.99% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FNBGX Fidelity Long-Term Treasury Bond Index Fund	3.99%	3.88%	3.75%	3.20%	2.26%	2.47%	3.96%	2.63%	2.93%	0.70%	0.00%	0.00%
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 FXNAX and FNBGX in my portfolio?

With a correlation of 0.91, FXNAX and FNBGX 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, FXNAX or FNBGX?

FNBGX has higher volatility (2.09%) compared to FXNAX (1.16%). In terms of maximum drawdown, FXNAX dropped -19.51% vs FNBGX's -46.86%.

Which has better risk-adjusted returns?

FXNAX currently has the higher Sharpe Ratio (1.14 vs 0.50), 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.