MFBFX vs. MFIOX

Last updated Jun 24, 2026

MFBFX (MFS Corporate Bond Fund) and MFIOX (MFS Income Fund) are both mutual funds - MFBFX is a Corporate Bonds fund managed by MFS, while MFIOX is a Intermediate Core-Plus Bond fund managed by MFS. Over the past 10 years, MFBFX returned 2.34%/yr vs 2.69%/yr for MFIOX. A 0.72 correlation means they provide meaningful diversification when combined. MFBFX charges 0.76%/yr vs 0.73%/yr for MFIOX.

Performance

MFBFX vs. MFIOX - Performance Comparison

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

Returns By Period

In the year-to-date period, MFBFX achieves a 0.37% return, which is significantly higher than MFIOX's 0.28% return. Over the past 10 years, MFBFX has underperformed MFIOX with an annualized return of 2.34%, while MFIOX has yielded a comparatively higher 2.69% annualized return.

MFBFX

• 1D: -0.32%
• 1M: 0.69%
• YTD: 0.37%
• 6M: 0.76%
• 1Y: 4.86%
• 3Y*: 4.79%
• 5Y*: -0.22%
• 10Y*: 2.34%

MFIOX

• 1D: -0.34%
• 1M: 0.58%
• YTD: 0.28%
• 6M: 0.67%
• 1Y: 4.59%
• 3Y*: 4.94%
• 5Y*: 0.54%
• 10Y*: 2.69%

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

MFBFX vs. MFIOX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
MFBFX MFS Corporate Bond Fund	0.37%	7.35%	2.03%	8.09%	-17.27%	-1.47%	11.01%	14.43%	-3.19%	6.08%
MFIOX MFS Income Fund	0.28%	7.37%	2.66%	7.46%	-14.14%	-0.28%	9.47%	11.36%	-2.38%	5.73%

Correlation

The correlation between MFBFX and MFIOX 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, MFBFX and MFIOX have become more correlated (0.94) than their long-term average of 0.72, meaning their price movements have been converging.

Return for Risk

MFBFX vs. MFIOX — Risk / Return Rank

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

MFBFX

MFBFX Risk / Return Rank: 22
MFBFX Sharpe Ratio Rank: 22
MFBFX Sortino Ratio Rank: 22
MFBFX Omega Ratio Rank: 20
MFBFX Calmar Ratio Rank: 22
MFBFX Martin Ratio Rank: 23

MFIOX

MFIOX Risk / Return Rank: 26
MFIOX Sharpe Ratio Rank: 26
MFIOX Sortino Ratio Rank: 28
MFIOX Omega Ratio Rank: 27
MFIOX Calmar Ratio Rank: 26
MFIOX 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.

MFBFX vs. MFIOX - Risk-Adjusted Trends Comparison

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

	MFBFX	MFIOX	Difference
Sharpe ratio: Return per unit of total volatility	1.23	1.36	-0.13
Sortino ratio: Return per unit of downside risk	1.83	2.06	-0.23
Omega ratio: Gain probability vs. loss probability	1.22	1.25	-0.03
Calmar ratio: Return relative to maximum drawdown	1.59	1.77	-0.17
Martin ratio: Return relative to average drawdown	5.19	5.39	-0.19

MFBFX vs. MFIOX - Sharpe Ratio Comparison

The current MFBFX Sharpe Ratio is 1.23, which is comparable to the MFIOX Sharpe Ratio of 1.36. The chart below compares the historical Sharpe Ratios of MFBFX and MFIOX, 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

MFBFX vs. MFIOX - Drawdown Comparison

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

Drawdown Indicators

	MFBFX	MFIOX	Difference
Max Drawdown Largest peak-to-trough decline	-29.78%	-19.07%	-10.71%
Max Drawdown (1Y) Largest decline over 1 year	-3.17%	-2.81%	-0.36%
Max Drawdown (3Y) Largest decline over 3 years	-6.83%	-5.88%	-0.95%
Max Drawdown (5Y) Largest decline over 5 years	-23.44%	-19.07%	-4.37%
Max Drawdown (10Y) Largest decline over 10 years	-23.44%	-19.07%	-4.37%
Current Drawdown Current decline from peak	-3.19%	-1.30%	-1.89%
Average Drawdown Average peak-to-trough decline	-6.19%	-2.18%	-4.01%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.97%	0.92%	+0.05%

Volatility

MFBFX vs. MFIOX - Volatility Comparison

MFS Corporate Bond Fund (MFBFX) has a higher volatility of 1.17% compared to MFS Income Fund (MFIOX) at 1.11%. This indicates that MFBFX's price experiences larger fluctuations and is considered to be riskier than MFIOX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	MFBFX	MFIOX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.17%	1.11%	+0.06%
Volatility (6M) Calculated over the trailing 6-month period	3.09%	2.71%	+0.38%
Volatility (1Y) Calculated over the trailing 1-year period	4.10%	3.65%	+0.45%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	6.40%	5.52%	+0.88%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	5.74%	4.88%	+0.86%

MFBFX vs. MFIOX - Expense Ratio Comparison

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

Dividends

MFBFX vs. MFIOX - Dividend Comparison

MFBFX's dividend yield for the trailing twelve months is around 4.54%, less than MFIOX's 4.71% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
MFBFX MFS Corporate Bond Fund	4.54%	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	4.71%	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 MFBFX and MFIOX in my portfolio?

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

MFBFX has higher volatility (1.17%) compared to MFIOX (1.11%). In terms of maximum drawdown, MFBFX dropped -29.78% vs MFIOX's -19.07%.

Which has better risk-adjusted returns?

MFIOX currently has the higher Sharpe Ratio (1.36 vs 1.23), 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.