MFGSX vs. FUTBX

Last updated Jun 4, 2026

MFGSX (MFS Government Securities Fund) and FUTBX (Fidelity SAI U.S. Treasury Bond Index Fund) are both Government Bonds funds. Over the past 5 years, MFGSX returned -0.79%/yr vs -0.41%/yr for FUTBX. Their correlation of 0.93 suggests significant overlap in exposure. MFGSX charges 0.76%/yr vs 0.03%/yr for FUTBX.

Performance

MFGSX vs. FUTBX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MFS Government Securities Fund (MFGSX) and Fidelity SAI U.S. Treasury Bond Index Fund (FUTBX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MFGSX achieves a -0.15% return, which is significantly lower than FUTBX's 0.07% return.

MFGSX

• 1D: 0.00%
• 1M: 0.30%
• YTD: -0.15%
• 6M: -0.33%
• 1Y: 4.32%
• 3Y*: 2.53%
• 5Y*: -0.79%
• 10Y*: 0.56%

FUTBX

• 1D: 0.00%
• 1M: 0.26%
• YTD: 0.07%
• 6M: -0.22%
• 1Y: 4.03%
• 3Y*: 2.91%
• 5Y*: -0.41%
• 10Y*: —

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

MFGSX vs. FUTBX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MFGSX MFS Government Securities Fund	-0.15%	6.62%	-0.16%	3.28%	-12.54%	-2.18%	6.25%	6.20%	0.27%	1.82%
FUTBX Fidelity SAI U.S. Treasury Bond Index Fund	0.07%	6.12%	0.70%	4.19%	-13.00%	-2.54%	7.76%	7.30%	0.95%	2.28%

Correlation

The correlation between MFGSX and FUTBX is 0.96 - 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	0.96
Correlation (3Y) Calculated over the trailing 3-year period	0.96
Correlation (5Y) Calculated over the trailing 5-year period	0.96
Correlation (All Time) Calculated using the full available price history since Jan 4, 2017	0.93

The correlation between MFGSX and FUTBX has been stable across timeframes, ranging from 0.93 to 0.96 - a consistent structural relationship.

Return for Risk

MFGSX vs. FUTBX — Risk / Return Rank

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

MFGSX

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

FUTBX

FUTBX Risk / Return Rank: 13
FUTBX Sharpe Ratio Rank: 14
FUTBX Sortino Ratio Rank: 14
FUTBX Omega Ratio Rank: 12
FUTBX Calmar Ratio Rank: 14
FUTBX Martin Ratio Rank: 13

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.

MFGSX vs. FUTBX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MFS Government Securities Fund (MFGSX) and Fidelity SAI U.S. Treasury Bond Index Fund (FUTBX). 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.

	MFGSX	FUTBX	Difference
Sharpe ratio: Return per unit of total volatility	1.06	1.02	+0.04
Sortino ratio: Return per unit of downside risk	1.57	1.51	+0.06
Omega ratio: Gain probability vs. loss probability	1.19	1.18	+0.01
Calmar ratio: Return relative to maximum drawdown	1.28	1.28	0.00
Martin ratio: Return relative to average drawdown	3.88	3.75	+0.14
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

MFGSX vs. FUTBX - Sharpe Ratio Comparison

The current MFGSX Sharpe Ratio is 1.06, which is comparable to the FUTBX Sharpe Ratio of 1.02. The chart below compares the historical Sharpe Ratios of MFGSX and FUTBX, 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

	MFGSX	FUTBX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.06	1.02	+0.04
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	-0.13	-0.07	-0.06
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.12	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.81	0.25	+0.56

Drawdowns

MFGSX vs. FUTBX - Drawdown Comparison

The maximum MFGSX drawdown since its inception was -19.50%, roughly equal to the maximum FUTBX drawdown of -19.69%. Use the drawdown chart below to compare losses from any high point for MFGSX and FUTBX.

Drawdown Indicators

	MFGSX	FUTBX	Difference
Max Drawdown Largest peak-to-trough decline	-19.50%	-19.69%	+0.19%
Max Drawdown (1Y) Largest decline over 1 year	-3.39%	-3.09%	-0.30%
Max Drawdown (3Y) Largest decline over 3 years	-6.92%	-5.42%	-1.50%
Max Drawdown (5Y) Largest decline over 5 years	-18.14%	-17.03%	-1.11%
Max Drawdown (10Y) Largest decline over 10 years	-19.50%	—	—
Current Drawdown Current decline from peak	-6.92%	-7.62%	+0.70%
Average Drawdown Average peak-to-trough decline	-3.31%	-6.96%	+3.65%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.11%	1.05%	+0.06%

Volatility

MFGSX vs. FUTBX - Volatility Comparison

MFS Government Securities Fund (MFGSX) has a higher volatility of 1.45% compared to Fidelity SAI U.S. Treasury Bond Index Fund (FUTBX) at 1.20%. This indicates that MFGSX's price experiences larger fluctuations and is considered to be riskier than FUTBX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MFGSX	FUTBX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.45%	1.20%	+0.25%
Volatility (6M) Calculated over the trailing 6-month period	2.93%	2.72%	+0.21%
Volatility (1Y) Calculated over the trailing 1-year period	4.10%	3.87%	+0.23%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	5.92%	5.81%	+0.11%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	4.78%	5.15%	-0.37%

MFGSX vs. FUTBX - Expense Ratio Comparison

MFGSX has a 0.76% expense ratio, which is higher than FUTBX's 0.03% expense ratio.

Dividends

MFGSX vs. FUTBX - Dividend Comparison

MFGSX's dividend yield for the trailing twelve months is around 3.56%, less than FUTBX's 3.65% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FUTBX Fidelity SAI U.S. Treasury Bond Index Fund	3.65%	3.43%	2.90%	2.12%	1.12%	0.86%	4.54%	2.75%	2.05%	1.65%	0.00%	0.00%
MFGSX MFS Government Securities Fund	3.56%	3.47%	3.13%	2.51%	1.19%	1.03%	1.83%	2.11%	2.32%	2.43%	2.31%	2.16%

Frequently Asked Questions

Can I hold both MFGSX and FUTBX in my portfolio?

With a correlation of 0.96, MFGSX and FUTBX 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, MFGSX or FUTBX?

MFGSX has higher volatility (1.45%) compared to FUTBX (1.20%). In terms of maximum drawdown, MFGSX dropped -19.50% vs FUTBX's -19.69%.

Which has better risk-adjusted returns?

MFGSX currently has the higher Sharpe Ratio (1.06 vs 1.02), 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.