MGF vs. FBLTX

Last updated Jun 23, 2026

MGF (MFS Government Markets Income Trust) and FBLTX (Fidelity SAI Long-Term Treasury Bond Index Fund) are both Government Bonds funds. Over the past 10 years, MGF returned 1.37%/yr vs -1.63%/yr for FBLTX. At a 0.24 correlation, their price movements are largely independent. MGF charges 0.02%/yr vs 0.03%/yr for FBLTX.

Performance

MGF vs. FBLTX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MFS Government Markets Income Trust (MGF) and Fidelity SAI Long-Term Treasury Bond Index Fund (FBLTX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MGF achieves a -2.10% return, which is significantly lower than FBLTX's 0.98% return. Over the past 10 years, MGF has outperformed FBLTX with an annualized return of 1.37%, while FBLTX has yielded a comparatively lower -1.63% annualized return.

MGF

• 1D: 0.00%
• 1M: 0.64%
• YTD: -2.10%
• 6M: -0.29%
• 1Y: 0.15%
• 3Y*: 3.60%
• 5Y*: -0.77%
• 10Y*: 1.37%

FBLTX

• 1D: 0.45%
• 1M: 2.83%
• YTD: 0.98%
• 6M: 1.18%
• 1Y: 4.79%
• 3Y*: -1.52%
• 5Y*: -6.98%
• 10Y*: -1.63%

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

MGF vs. FBLTX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MGF MFS Government Markets Income Trust	-2.10%	6.24%	4.17%	3.78%	-15.81%	-0.22%	7.80%	10.32%	1.33%	2.62%
FBLTX Fidelity SAI Long-Term Treasury Bond Index Fund	0.98%	4.39%	-8.05%	2.71%	-31.84%	-4.89%	18.27%	14.36%	-1.24%	9.06%

Correlation

The correlation between MGF and FBLTX is 0.22, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.22
Correlation (3Y) Calculated over the trailing 3-year period	0.36
Correlation (5Y) Calculated over the trailing 5-year period	0.33
Correlation (10Y) Calculated over the trailing 10-year period	0.25
Correlation (All Time) Calculated using the full available price history since Oct 16, 2015	0.24

The correlation between MGF and FBLTX shifts across timeframes, from 0.22 (1 year) to 0.36 (3 years), reflecting how their relationship changes across market environments.

Return for Risk

MGF vs. FBLTX — Risk / Return Rank

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

MGF

MGF Risk / Return Rank: 3
MGF Sharpe Ratio Rank: 3
MGF Sortino Ratio Rank: 3
MGF Omega Ratio Rank: 3
MGF Calmar Ratio Rank: 3
MGF Martin Ratio Rank: 3

FBLTX

FBLTX Risk / Return Rank: 6
FBLTX Sharpe Ratio Rank: 7
FBLTX Sortino Ratio Rank: 6
FBLTX Omega Ratio Rank: 6
FBLTX Calmar Ratio Rank: 7
FBLTX 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.

MGF vs. FBLTX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MFS Government Markets Income Trust (MGF) and Fidelity SAI Long-Term Treasury Bond Index Fund (FBLTX). 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.

	MGF	FBLTX	Difference
Sharpe ratio: Return per unit of total volatility	0.01	0.50	-0.48
Sortino ratio: Return per unit of downside risk	0.09	0.78	-0.68
Omega ratio: Gain probability vs. loss probability	1.01	1.09	-0.08
Calmar ratio: Return relative to maximum drawdown	0.03	0.61	-0.59
Martin ratio: Return relative to average drawdown	0.06	1.48	-1.42

MGF vs. FBLTX - Sharpe Ratio Comparison

The current MGF Sharpe Ratio is 0.01, which is lower than the FBLTX Sharpe Ratio of 0.50. The chart below compares the historical Sharpe Ratios of MGF and FBLTX, 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

MGF vs. FBLTX - Drawdown Comparison

The maximum MGF drawdown since its inception was -35.74%, smaller than the maximum FBLTX drawdown of -49.06%. Use the drawdown chart below to compare losses from any high point for MGF and FBLTX.

Drawdown Indicators

	MGF	FBLTX	Difference
Max Drawdown Largest peak-to-trough decline	-35.74%	-49.06%	+13.32%
Max Drawdown (1Y) Largest decline over 1 year	-6.05%	-7.66%	+1.61%
Max Drawdown (3Y) Largest decline over 3 years	-8.94%	-19.12%	+10.18%
Max Drawdown (5Y) Largest decline over 5 years	-22.88%	-44.19%	+21.31%
Max Drawdown (10Y) Largest decline over 10 years	-22.88%	-49.06%	+26.18%
Current Drawdown Current decline from peak	-6.84%	-40.38%	+33.54%
Average Drawdown Average peak-to-trough decline	-10.87%	-21.07%	+10.20%
Ulcer Index Depth and duration of drawdowns from previous peaks	2.81%	3.16%	-0.35%

Volatility

MGF vs. FBLTX - Volatility Comparison

MFS Government Markets Income Trust (MGF) has a higher volatility of 4.01% compared to Fidelity SAI Long-Term Treasury Bond Index Fund (FBLTX) at 2.11%. This indicates that MGF's price experiences larger fluctuations and is considered to be riskier than FBLTX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MGF	FBLTX	Difference
Volatility (1M) Calculated over the trailing 1-month period	4.01%	2.11%	+1.90%
Volatility (6M) Calculated over the trailing 6-month period	7.68%	6.53%	+1.15%
Volatility (1Y) Calculated over the trailing 1-year period	10.52%	9.43%	+1.09%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	11.32%	15.65%	-4.33%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	10.19%	14.59%	-4.40%

MGF vs. FBLTX - Expense Ratio Comparison

MGF has a 0.02% expense ratio, which is lower than FBLTX'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

MGF vs. FBLTX - Dividend Comparison

MGF's dividend yield for the trailing twelve months is around 8.03%, more than FBLTX's 4.12% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FBLTX Fidelity SAI Long-Term Treasury Bond Index Fund	4.12%	4.04%	3.60%	3.29%	2.25%	1.81%	6.73%	2.39%	2.87%	2.68%	3.70%	0.39%
MGF MFS Government Markets Income Trust	8.03%	7.65%	7.81%	7.82%	8.45%	7.71%	7.58%	7.50%	7.81%	7.92%	8.09%	8.05%

Frequently Asked Questions

Can I hold both MGF and FBLTX in my portfolio?

MGF and FBLTX have a correlation of 0.22, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, MGF or FBLTX?

MGF has higher volatility (4.01%) compared to FBLTX (2.11%). In terms of maximum drawdown, MGF dropped -35.74% vs FBLTX's -49.06%.

Which has better risk-adjusted returns?

FBLTX currently has the higher Sharpe Ratio (0.50 vs 0.01), 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.