MFIOX vs. MFBFX

Last updated Jun 23, 2026

MFIOX (MFS Income Fund) and MFBFX (MFS Corporate Bond Fund) are both mutual funds - MFIOX is a Intermediate Core-Plus Bond fund managed by MFS, while MFBFX is a Corporate Bonds fund managed by MFS. Over the past 10 years, MFIOX returned 2.72%/yr vs 2.40%/yr for MFBFX. A 0.72 correlation means they provide meaningful diversification when combined. MFIOX charges 0.73%/yr vs 0.76%/yr for MFBFX.

Performance

MFIOX vs. MFBFX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in MFS Income Fund (MFIOX) and MFS Corporate Bond Fund (MFBFX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, MFIOX achieves a 0.63% return, which is significantly lower than MFBFX's 0.70% return. Over the past 10 years, MFIOX has outperformed MFBFX with an annualized return of 2.72%, while MFBFX has yielded a comparatively lower 2.40% annualized return.

MFIOX

• 1D: 0.17%
• 1M: 0.92%
• YTD: 0.63%
• 6M: 1.01%
• 1Y: 5.31%
• 3Y*: 5.05%
• 5Y*: 0.55%
• 10Y*: 2.72%

MFBFX

• 1D: 0.24%
• 1M: 1.02%
• YTD: 0.70%
• 6M: 1.08%
• 1Y: 5.37%
• 3Y*: 4.90%
• 5Y*: -0.25%
• 10Y*: 2.40%

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

MFIOX vs. MFBFX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MFIOX MFS Income Fund	0.63%	7.37%	2.66%	7.46%	-14.14%	-0.28%	9.47%	11.36%	-2.38%	5.73%
MFBFX MFS Corporate Bond Fund	0.70%	7.35%	2.03%	8.09%	-17.27%	-1.47%	11.01%	14.43%	-3.19%	6.08%

Correlation

The correlation between MFIOX and MFBFX is 0.94, 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	0.94
Correlation (3Y) Calculated over the trailing 3-year period	0.95
Correlation (5Y) Calculated over the trailing 5-year period	0.95
Correlation (10Y) Calculated over the trailing 10-year period	0.92
Correlation (All Time) Calculated using the full available price history since Oct 29, 1987	0.72

Over the past year, MFIOX and MFBFX have become more correlated (0.94) than their long-term average of 0.72, meaning their price movements have been converging.

Return for Risk

MFIOX vs. MFBFX — Risk / Return Rank

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

MFIOX

MFIOX Risk / Return Rank: 30
MFIOX Sharpe Ratio Rank: 30
MFIOX Sortino Ratio Rank: 33
MFIOX Omega Ratio Rank: 31
MFIOX Calmar Ratio Rank: 29
MFIOX Martin Ratio Rank: 26

MFBFX

MFBFX Risk / Return Rank: 25
MFBFX Sharpe Ratio Rank: 25
MFBFX Sortino Ratio Rank: 26
MFBFX Omega Ratio Rank: 24
MFBFX Calmar Ratio Rank: 25
MFBFX Martin Ratio Rank: 25

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.

MFIOX vs. MFBFX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MFS Income Fund (MFIOX) and MFS Corporate Bond Fund (MFBFX). 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.

	MFIOX	MFBFX	Difference
Sharpe ratio: Return per unit of total volatility	1.47	1.34	+0.13
Sortino ratio: Return per unit of downside risk	2.22	1.99	+0.23
Omega ratio: Gain probability vs. loss probability	1.27	1.24	+0.03
Calmar ratio: Return relative to maximum drawdown	1.89	1.73	+0.16
Martin ratio: Return relative to average drawdown	5.80	5.65	+0.15

MFIOX vs. MFBFX - Sharpe Ratio Comparison

The current MFIOX Sharpe Ratio is 1.47, which is comparable to the MFBFX Sharpe Ratio of 1.34. The chart below compares the historical Sharpe Ratios of MFIOX and MFBFX, 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

MFIOX vs. MFBFX - Drawdown Comparison

The maximum MFIOX drawdown since its inception was -19.07%, smaller than the maximum MFBFX drawdown of -29.78%. Use the drawdown chart below to compare losses from any high point for MFIOX and MFBFX.

Drawdown Indicators

	MFIOX	MFBFX	Difference
Max Drawdown Largest peak-to-trough decline	-19.07%	-29.78%	+10.71%
Max Drawdown (1Y) Largest decline over 1 year	-2.81%	-3.17%	+0.36%
Max Drawdown (3Y) Largest decline over 3 years	-5.88%	-6.83%	+0.95%
Max Drawdown (5Y) Largest decline over 5 years	-19.07%	-23.44%	+4.37%
Max Drawdown (10Y) Largest decline over 10 years	-19.07%	-23.44%	+4.37%
Current Drawdown Current decline from peak	-0.97%	-2.87%	+1.90%
Average Drawdown Average peak-to-trough decline	-2.18%	-6.19%	+4.01%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.92%	0.97%	-0.05%

Volatility

MFIOX vs. MFBFX - Volatility Comparison

The current volatility for MFS Income Fund (MFIOX) is 1.14%, while MFS Corporate Bond Fund (MFBFX) has a volatility of 1.21%. This indicates that MFIOX experiences smaller price fluctuations and is considered to be less risky than MFBFX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MFIOX	MFBFX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.14%	1.21%	-0.07%
Volatility (6M) Calculated over the trailing 6-month period	2.69%	3.07%	-0.38%
Volatility (1Y) Calculated over the trailing 1-year period	3.63%	4.08%	-0.45%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	5.52%	6.40%	-0.88%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	4.88%	5.74%	-0.86%

MFIOX vs. MFBFX - Expense Ratio Comparison

MFIOX has a 0.73% expense ratio, which is lower than MFBFX's 0.76% expense ratio.

Dividends

MFIOX vs. MFBFX - Dividend Comparison

MFIOX's dividend yield for the trailing twelve months is around 4.70%, more than MFBFX's 4.53% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MFBFX MFS Corporate Bond Fund	4.53%	4.54%	3.74%	3.16%	2.46%	5.61%	3.47%	3.01%	3.15%	3.07%	3.27%	4.16%
MFIOX MFS Income Fund	4.70%	4.70%	5.04%	4.72%	2.24%	3.29%	2.80%	3.04%	3.07%	3.26%	3.61%	4.35%

Frequently Asked Questions

Can I hold both MFIOX and MFBFX in my portfolio?

With a correlation of 0.94, MFIOX and MFBFX 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, MFIOX or MFBFX?

MFBFX has higher volatility (1.21%) compared to MFIOX (1.14%). In terms of maximum drawdown, MFIOX dropped -19.07% vs MFBFX's -29.78%.

Which has better risk-adjusted returns?

MFIOX currently has the higher Sharpe Ratio (1.47 vs 1.34), 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.