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MFIOX vs. SPAXX
Performance
Return for Risk
Drawdowns
Volatility
Dividends

MFIOX vs. SPAXX

Last updated Jun 24, 2026

MFIOX (MFS Income Fund) and SPAXX (Fidelity Government Money Market Fund) are both mutual funds - MFIOX is a Intermediate Core-Plus Bond fund managed by MFS, while SPAXX is a Money Market fund actively managed by Fidelity. Over the past 5 years, MFIOX returned 0.54%/yr vs 1.45%/yr for SPAXX. At a 0.17 correlation, their price movements are largely independent. MFIOX charges 0.73%/yr vs 0.42%/yr for SPAXX.

Performance

MFIOX vs. SPAXX - Performance Comparison

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

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Returns By Period

In the year-to-date period, MFIOX achieves a 0.28% return, which is significantly lower than SPAXX's 1.37% return.

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%

SPAXX

1D
0.00%
1M
0.28%
YTD
1.37%
6M
1.67%
1Y
3.66%
3Y*
2.42%
5Y*
1.45%
10Y*
—
*Multi-year figures are annualized to reflect compound growth (CAGR)

MFIOX vs. SPAXX - Yearly Performance Comparison

2026 (YTD)20252024202320222021
MFIOX
MFS Income Fund		0.28%7.37%2.66%7.46%-14.14%1.60%
SPAXX
Fidelity Government Money Market Fund		1.37%3.96%1.54%0.41%0.00%0.00%

Correlation

The correlation between MFIOX and SPAXX is 0.32, which is low. Their price movements are largely independent, making them effective diversification partners.

Correlation
Correlation (1Y)
Calculated over the trailing 1-year period

0.32

Correlation (3Y)
Calculated over the trailing 3-year period

0.22

Correlation (5Y)
Calculated over the trailing 5-year period

0.17

Correlation (All Time)
Calculated using the full available price history since May 25, 2021

0.17

The correlation between MFIOX and SPAXX shifts across timeframes, from 0.17 (all time) to 0.32 (1 year), reflecting how their relationship changes across market environments.

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MFS Income Fund

Fidelity Government Money Market Fund

Often compared with MFIOX:
MFIOX vs. MACIXMFIOX vs. MFBFXMFIOX vs. MHITXMFIOX vs. MHOIXMFIOX vs. MEIAXMFIOX vs. FPURXMFIOX vs. MSFRX
Often compared with SPAXX:
SPAXX vs. SGOVSPAXX vs. VMFXXSPAXX vs. SNSXXSPAXX vs. SWVXXSPAXX vs. BILSPAXX vs. BNDSPAXX vs. TFLO

Return for Risk

MFIOX vs. SPAXX — Risk / Return Rank

Compare risk-adjusted metric ranks to identify better-performing investments over the past 12 months.
MFIOX
MFIOX Risk / Return Rank: 2626
Overall Rank
MFIOX Sharpe Ratio Rank: 2626
Sharpe Ratio Rank
MFIOX Sortino Ratio Rank: 2828
Sortino Ratio Rank
MFIOX Omega Ratio Rank: 2727
Omega Ratio Rank
MFIOX Calmar Ratio Rank: 2626
Calmar Ratio Rank
MFIOX Martin Ratio Rank: 2525
Martin Ratio Rank
SPAXX

Risk / return metrics aren't available yet — we need at least 12 months of trading data to calculate them.

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. SPAXX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for MFS Income Fund (MFIOX) and Fidelity Government Money Market Fund (SPAXX). 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.

MFIOXSPAXXDifference
Sharpe ratioReturn per unit of total volatility
1.36
3.65

-2.28

Sortino ratioReturn per unit of downside risk
2.06

—

—

Omega ratioGain probability vs. loss probability

1.25

—

—

Calmar ratioReturn relative to maximum drawdown

1.77

—

—

Martin ratioReturn relative to average drawdown

5.39

—

—

MFIOX vs. SPAXX - Sharpe Ratio Comparison

The current MFIOX Sharpe Ratio is 1.36, which is lower than the SPAXX Sharpe Ratio of 3.65. The chart below compares the historical Sharpe Ratios of MFIOX and SPAXX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

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Drawdowns

MFIOX vs. SPAXX - Drawdown Comparison

The maximum MFIOX drawdown since its inception was -19.07%, which is greater than SPAXX's maximum drawdown of 0.00%. Use the drawdown chart below to compare losses from any high point for MFIOX and SPAXX.

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Drawdown Indicators

MFIOXSPAXXDifference

Max Drawdown

Largest peak-to-trough decline

-19.07%

0.00%

-19.07%

Max Drawdown (1Y)

Largest decline over 1 year

-2.81%

0.00%

-2.81%

Max Drawdown (3Y)

Largest decline over 3 years

-5.88%

0.00%

-5.88%

Max Drawdown (5Y)

Largest decline over 5 years

-19.07%

0.00%

-19.07%

Max Drawdown (10Y)

Largest decline over 10 years

-19.07%

—

—

Current Drawdown

Current decline from peak

-1.30%

0.00%

-1.30%

Average Drawdown

Average peak-to-trough decline

-2.18%

0.00%

-2.18%

Ulcer Index

Depth and duration of drawdowns from previous peaks

0.92%

0.00%

+0.92%

Volatility

MFIOX vs. SPAXX - Volatility Comparison

MFS Income Fund (MFIOX) has a higher volatility of 1.11% compared to Fidelity Government Money Market Fund (SPAXX) at 0.28%. This indicates that MFIOX's price experiences larger fluctuations and is considered to be riskier than SPAXX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

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Volatility by Period

MFIOXSPAXXDifference

Volatility (1M)

Calculated over the trailing 1-month period

1.11%

0.28%

+0.83%

Volatility (6M)

Calculated over the trailing 6-month period

2.71%

0.66%

+2.05%

Volatility (1Y)

Calculated over the trailing 1-year period

3.65%

1.03%

+2.62%

Volatility (5Y)

Calculated over the trailing 5-year period, annualized

5.52%

0.69%

+4.83%

Volatility (10Y)

Calculated over the trailing 10-year period, annualized

4.88%

0.69%

+4.19%

MFIOX vs. SPAXX - Expense Ratio Comparison

MFIOX has a 0.73% expense ratio, which is higher than SPAXX's 0.42% expense ratio.

Dividends

MFIOX vs. SPAXX - Dividend Comparison

MFIOX's dividend yield for the trailing twelve months is around 4.71%, more than SPAXX's 3.59% yield.

PositionTTM20252024202320222021202020192018201720162015
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%
SPAXX
Fidelity Government Money Market Fund		3.59%3.88%1.53%0.41%0.00%0.00%0.00%0.00%0.00%0.00%0.00%0.00%

Frequently Asked Questions

MFIOX and SPAXX have a correlation of 0.32, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

MFIOX has higher volatility (1.11%) compared to SPAXX (0.28%). In terms of maximum drawdown, MFIOX dropped -19.07% vs SPAXX's 0.00%.

SPAXX currently has the higher Sharpe Ratio (3.65 vs 1.36), 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.

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