AMUSX vs. FNBGX

Last updated Jun 4, 2026

AMUSX (American Funds U.S. Government Securities Fund) and FNBGX (Fidelity Long-Term Treasury Bond Index Fund) are both Government Bonds funds. Over the past 5 years, AMUSX returned -0.13%/yr vs -5.10%/yr for FNBGX. Their correlation of 0.84 suggests significant overlap in exposure. AMUSX charges 0.61%/yr vs 0.03%/yr for FNBGX.

Performance

AMUSX vs. FNBGX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Funds U.S. Government Securities Fund (AMUSX) 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, AMUSX achieves a -0.35% return, which is significantly lower than FNBGX's 0.02% return.

AMUSX

• 1D: 0.00%
• 1M: 0.28%
• YTD: -0.35%
• 6M: -0.26%
• 1Y: 4.29%
• 3Y*: 3.14%
• 5Y*: -0.13%
• 10Y*: 1.14%

FNBGX

• 1D: 0.22%
• 1M: 1.23%
• YTD: 0.02%
• 6M: -1.23%
• 1Y: 5.75%
• 3Y*: -0.54%
• 5Y*: -5.10%
• 10Y*: —

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

AMUSX vs. FNBGX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
AMUSX American Funds U.S. Government Securities Fund	-0.35%	7.55%	0.63%	2.79%	-11.50%	-0.84%	9.44%	5.03%	0.64%	-0.47%
FNBGX Fidelity Long-Term Treasury Bond Index Fund	0.02%	5.30%	-6.18%	3.20%	-29.89%	-5.17%	17.58%	14.24%	-1.62%	1.86%

Correlation

The correlation between AMUSX and FNBGX is 0.85, 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	0.85
Correlation (3Y) Calculated over the trailing 3-year period	0.86
Correlation (5Y) Calculated over the trailing 5-year period	0.86
Correlation (All Time) Calculated using the full available price history since Oct 20, 2017	0.85

The correlation between AMUSX and FNBGX has been stable across timeframes, ranging from 0.84 to 0.86 - a consistent structural relationship.

Return for Risk

AMUSX vs. FNBGX — Risk / Return Rank

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

AMUSX

AMUSX Risk / Return Rank: 14
AMUSX Sharpe Ratio Rank: 14
AMUSX Sortino Ratio Rank: 15
AMUSX Omega Ratio Rank: 14
AMUSX Calmar Ratio Rank: 13
AMUSX Martin Ratio Rank: 14

FNBGX

FNBGX Risk / Return Rank: 7
FNBGX Sharpe Ratio Rank: 8
FNBGX Sortino Ratio Rank: 7
FNBGX Omega Ratio Rank: 7
FNBGX Calmar Ratio Rank: 8
FNBGX Martin Ratio Rank: 7

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.

AMUSX vs. FNBGX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Funds U.S. Government Securities Fund (AMUSX) 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.

	AMUSX	FNBGX	Difference
Sharpe ratio: Return per unit of total volatility	1.04	0.63	+0.41
Sortino ratio: Return per unit of downside risk	1.58	0.96	+0.62
Omega ratio: Gain probability vs. loss probability	1.19	1.11	+0.08
Calmar ratio: Return relative to maximum drawdown	1.26	0.78	+0.49
Martin ratio: Return relative to average drawdown	3.97	2.06	+1.91
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

AMUSX vs. FNBGX - Sharpe Ratio Comparison

The current AMUSX Sharpe Ratio is 1.04, which is higher than the FNBGX Sharpe Ratio of 0.63. The chart below compares the historical Sharpe Ratios of AMUSX 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.

Sharpe Ratios by Period

	AMUSX	FNBGX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.04	0.63	+0.41
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	-0.02	-0.35	+0.33
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.24	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.83	-0.07	+0.91

Drawdowns

AMUSX vs. FNBGX - Drawdown Comparison

The maximum AMUSX drawdown since its inception was -17.48%, smaller than the maximum FNBGX drawdown of -46.86%. Use the drawdown chart below to compare losses from any high point for AMUSX and FNBGX.

Drawdown Indicators

	AMUSX	FNBGX	Difference
Max Drawdown Largest peak-to-trough decline	-17.48%	-46.86%	+29.38%
Max Drawdown (1Y) Largest decline over 1 year	-3.35%	-7.28%	+3.93%
Max Drawdown (3Y) Largest decline over 3 years	-6.50%	-17.66%	+11.16%
Max Drawdown (5Y) Largest decline over 5 years	-16.84%	-41.54%	+24.70%
Max Drawdown (10Y) Largest decline over 10 years	-17.48%	—	—
Current Drawdown Current decline from peak	-3.24%	-37.24%	+34.00%
Average Drawdown Average peak-to-trough decline	-2.75%	-21.65%	+18.90%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.06%	2.74%	-1.68%

Volatility

AMUSX vs. FNBGX - Volatility Comparison

The current volatility for American Funds U.S. Government Securities Fund (AMUSX) is 1.54%, while Fidelity Long-Term Treasury Bond Index Fund (FNBGX) has a volatility of 2.79%. This indicates that AMUSX 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

	AMUSX	FNBGX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.54%	2.79%	-1.25%
Volatility (6M) Calculated over the trailing 6-month period	2.85%	6.13%	-3.28%
Volatility (1Y) Calculated over the trailing 1-year period	4.06%	9.03%	-4.97%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	6.06%	14.59%	-8.53%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	4.86%	14.20%	-9.34%

AMUSX vs. FNBGX - Expense Ratio Comparison

AMUSX has a 0.61% expense ratio, which is higher than FNBGX's 0.03% expense ratio.

Dividends

AMUSX vs. FNBGX - Dividend Comparison

AMUSX's dividend yield for the trailing twelve months is around 4.00%, which matches FNBGX's 4.00% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
AMUSX American Funds U.S. Government Securities Fund	4.00%	3.97%	4.19%	3.44%	2.01%	1.05%	4.92%	2.79%	1.72%	1.32%	2.30%	2.84%
FNBGX Fidelity Long-Term Treasury Bond Index Fund	4.00%	3.88%	3.75%	3.20%	2.26%	2.47%	3.96%	2.63%	2.93%	0.70%	0.00%	0.00%

Frequently Asked Questions

Can I hold both AMUSX and FNBGX in my portfolio?

AMUSX and FNBGX have a correlation of 0.85, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, AMUSX or FNBGX?

FNBGX has higher volatility (2.79%) compared to AMUSX (1.54%). In terms of maximum drawdown, AMUSX dropped -17.48% vs FNBGX's -46.86%.

Which has better risk-adjusted returns?

AMUSX currently has the higher Sharpe Ratio (1.04 vs 0.63), 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.