MFBFX vs. FXNAX
MFBFX (MFS Corporate Bond Fund) and FXNAX (Fidelity U.S. Bond Index Fund) are both mutual funds - MFBFX is a Corporate Bonds fund managed by MFS, while FXNAX is a Total Bond Market fund tracking the Bloomberg U.S. Aggregate Bond Index. Over the past 10 years, MFBFX returned 2.40%/yr vs 1.50%/yr for FXNAX. Their correlation of 0.89 suggests significant overlap in exposure. MFBFX charges 0.76%/yr vs 0.03%/yr for FXNAX.
Performance
MFBFX vs. FXNAX - Performance Comparison
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Returns By Period
In the year-to-date period, MFBFX achieves a 0.70% return, which is significantly higher than FXNAX's 0.40% return. Over the past 10 years, MFBFX has outperformed FXNAX with an annualized return of 2.40%, while FXNAX has yielded a comparatively lower 1.50% annualized return.
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%
FXNAX
- 1D
- 0.19%
- 1M
- 0.90%
- YTD
- 0.40%
- 6M
- 0.72%
- 1Y
- 4.76%
- 3Y*
- 4.02%
- 5Y*
- -0.06%
- 10Y*
- 1.50%
MFBFX vs. FXNAX - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
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% |
FXNAX Fidelity U.S. Bond Index Fund | 0.40% | 7.14% | 1.35% | 5.82% | -13.55% | -2.10% | 7.63% | 8.50% | 0.04% | 3.50% |
Correlation
The correlation between MFBFX and FXNAX 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 May 4, 2011 | 0.89 |
The correlation between MFBFX and FXNAX has been stable across timeframes, ranging from 0.89 to 0.95 - a consistent structural relationship.
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Return for Risk
MFBFX vs. FXNAX — Risk / Return Rank
MFBFX
FXNAX
MFBFX vs. FXNAX - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for MFS Corporate Bond Fund (MFBFX) and Fidelity U.S. Bond Index Fund (FXNAX). 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 | FXNAX | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | +0.12 | ||
| Sortino ratioReturn per unit of downside risk | +0.14 | ||
| Omega ratioGain probability vs. loss probability | 1.24 | 1.22 | +0.02 |
| Calmar ratioReturn relative to maximum drawdown | 1.73 | 1.62 | +0.11 |
| Martin ratioReturn relative to average drawdown | 5.65 | 4.68 | +0.97 |
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Drawdowns
MFBFX vs. FXNAX - Drawdown Comparison
The maximum MFBFX drawdown since its inception was -29.78%, which is greater than FXNAX's maximum drawdown of -19.51%. Use the drawdown chart below to compare losses from any high point for MFBFX and FXNAX.
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Drawdown Indicators
| MFBFX | FXNAX | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -29.78% | -19.51% | -10.27% |
Max Drawdown (1Y)Largest decline over 1 year | -3.17% | -2.94% | -0.23% |
Max Drawdown (3Y)Largest decline over 3 years | -6.83% | -6.16% | -0.67% |
Max Drawdown (5Y)Largest decline over 5 years | -23.44% | -18.54% | -4.90% |
Max Drawdown (10Y)Largest decline over 10 years | -23.44% | -19.51% | -3.93% |
Current DrawdownCurrent decline from peak | -2.87% | -2.89% | +0.02% |
Average DrawdownAverage peak-to-trough decline | -6.19% | -3.86% | -2.33% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 0.97% | 1.02% | -0.05% |
Volatility
MFBFX vs. FXNAX - Volatility Comparison
MFS Corporate Bond Fund (MFBFX) and Fidelity U.S. Bond Index Fund (FXNAX) have volatilities of 1.21% and 1.23%, respectively, indicating that both stocks experience similar levels of price fluctuations. This suggests that the risk associated with both stocks, as measured by volatility, is nearly the same. The chart below showcases a comparison of their rolling one-month volatility.
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Volatility by Period
| MFBFX | FXNAX | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 1.21% | 1.23% | -0.02% |
Volatility (6M)Calculated over the trailing 6-month period | 3.07% | 2.89% | +0.18% |
Volatility (1Y)Calculated over the trailing 1-year period | 4.08% | 3.90% | +0.18% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 6.40% | 6.08% | +0.32% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 5.74% | 5.01% | +0.73% |
MFBFX vs. FXNAX - Expense Ratio Comparison
MFBFX has a 0.76% expense ratio, which is higher than FXNAX's 0.03% expense ratio.
Dividends
MFBFX vs. FXNAX - Dividend Comparison
MFBFX's dividend yield for the trailing twelve months is around 4.53%, more than FXNAX's 3.71% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
FXNAX Fidelity U.S. Bond Index Fund | 3.71% | 3.58% | 3.40% | 3.15% | 1.81% | 1.74% | 2.92% | 2.68% | 2.74% | 2.57% | 2.76% | 2.52% |
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% |
Frequently Asked Questions
With a correlation of 0.94, MFBFX and FXNAX 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.
FXNAX has higher volatility (1.23%) compared to MFBFX (1.21%). In terms of maximum drawdown, MFBFX dropped -29.78% vs FXNAX's -19.51%.
MFBFX currently has the higher Sharpe Ratio (1.34 vs 1.22), 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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