MRBIX vs. SSASX

Last updated Apr 1, 2026

Compare and contrast key facts about MFS Total Return Bond Fund (MRBIX) and State Street Income Fund (SSASX).

MRBIX is managed by MFS. It was launched on Jan 4, 1999. SSASX is managed by State Street. It was launched on Jan 2, 1980.

Performance

MRBIX vs. SSASX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MFS Total Return Bond Fund (MRBIX) and State Street Income Fund (SSASX). The values are adjusted to include any dividend payments, if applicable.

MRBIX vs. SSASX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021
MRBIX MFS Total Return Bond Fund	-0.47%	7.35%	1.77%	6.45%	-14.52%	1.39%
SSASX State Street Income Fund	-0.61%	7.49%	-0.95%	4.83%	-13.74%	0.59%

Returns By Period

In the year-to-date period, MRBIX achieves a -0.47% return, which is significantly higher than SSASX's -0.61% return.

MRBIX

• 1D: 0.53%
• 1M: -2.25%
• YTD: -0.47%
• 6M: 0.50%
• 1Y: 3.94%
• 3Y*: 3.80%
• 5Y*: 0.24%
• 10Y*: 2.00%

SSASX

• 1D: 0.51%
• 1M: -2.48%
• YTD: -0.61%
• 6M: 0.37%
• 1Y: 3.71%
• 3Y*: 2.41%
• 5Y*: —
• 10Y*: —

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

MRBIX vs. SSASX - Expense Ratio Comparison

MRBIX has a 0.45% expense ratio, which is higher than SSASX's 0.20% expense ratio.

MRBIX

MFS Total Return Bond Fund

SSASX

State Street Income Fund

Return for Risk

MRBIX vs. SSASX — Risk / Return Rank

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

MRBIX

MRBIX Risk / Return Rank: 60
MRBIX Sharpe Ratio Rank: 59
MRBIX Sortino Ratio Rank: 60
MRBIX Omega Ratio Rank: 44
MRBIX Calmar Ratio Rank: 78
MRBIX Martin Ratio Rank: 57

SSASX

SSASX Risk / Return Rank: 44
SSASX Sharpe Ratio Rank: 42
SSASX Sortino Ratio Rank: 40
SSASX Omega Ratio Rank: 30
SSASX Calmar Ratio Rank: 67
SSASX Martin Ratio Rank: 42

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.

MRBIX vs. SSASX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MFS Total Return Bond Fund (MRBIX) and State Street Income Fund (SSASX). 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.

	MRBIX	SSASX	Difference
Sharpe ratio Return per unit of total volatility	1.07	0.90	+0.18
Sortino ratio Return per unit of downside risk	1.55	1.28	+0.26
Omega ratio Gain probability vs. loss probability	1.19	1.16	+0.03
Calmar ratio Return relative to maximum drawdown	1.84	1.58	+0.25
Martin ratio Return relative to average drawdown	5.51	4.37	+1.14
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

MRBIX vs. SSASX - Sharpe Ratio Comparison

The current MRBIX Sharpe Ratio is 1.07, which is comparable to the SSASX Sharpe Ratio of 0.90. The chart below compares the historical Sharpe Ratios of MRBIX and SSASX, offering insights into how both investments have performed under varying market conditions. These values are calculated using daily returns over the previous 12 months.

Sharpe Ratios by Period

	MRBIX	SSASX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.07	0.90	+0.18
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.04	—	—
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.41	—	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.97	-0.12	+1.09

Correlation

The correlation between MRBIX and SSASX is 0.97, which is considered to be high. That indicates a strong positive relationship between their price movements. Having highly-correlated positions in a portfolio may signal a lack of diversification, potentially leading to increased risk during market downturns.

Dividends

MRBIX vs. SSASX - Dividend Comparison

MRBIX's dividend yield for the trailing twelve months is around 3.89%, more than SSASX's 3.66% yield.

	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MRBIX MFS Total Return Bond Fund	3.89%	4.21%	3.69%	3.42%	2.39%	3.42%	3.00%	3.06%	2.87%	2.65%	3.02%	3.76%
SSASX State Street Income Fund	3.66%	4.01%	2.76%	2.86%	2.48%	3.77%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%

Drawdowns

MRBIX vs. SSASX - Drawdown Comparison

The maximum MRBIX drawdown since its inception was -19.25%, roughly equal to the maximum SSASX drawdown of -19.65%. Use the drawdown chart below to compare losses from any high point for MRBIX and SSASX.

Drawdown Indicators

	MRBIX	SSASX	Difference
Max Drawdown Largest peak-to-trough decline	-19.25%	-19.65%	+0.40%
Max Drawdown (1Y) Largest decline over 1 year	-2.77%	-3.12%	+0.35%
Max Drawdown (5Y) Largest decline over 5 years	-19.25%	—	—
Max Drawdown (10Y) Largest decline over 10 years	-19.25%	—	—
Current Drawdown Current decline from peak	-2.25%	-5.84%	+3.59%
Average Drawdown Average peak-to-trough decline	-2.48%	-9.83%	+7.35%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.92%	1.13%	-0.21%

Volatility

MRBIX vs. SSASX - Volatility Comparison

The current volatility for MFS Total Return Bond Fund (MRBIX) is 1.46%, while State Street Income Fund (SSASX) has a volatility of 1.60%. This indicates that MRBIX experiences smaller price fluctuations and is considered to be less risky than SSASX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MRBIX	SSASX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.46%	1.60%	-0.14%
Volatility (6M) Calculated over the trailing 6-month period	2.50%	2.76%	-0.26%
Volatility (1Y) Calculated over the trailing 1-year period	4.24%	4.82%	-0.58%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	5.70%	6.56%	-0.86%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	4.90%	6.56%	-1.66%