VBIUX vs. FMSFX

Last updated Jun 4, 2026

VBIUX (Vanguard Intermediate-Term Bond Index Fund Institutional Plus) and FMSFX (Fidelity Mortgage Securities Fund) are both Total Bond Market funds. Over the past 10 years, VBIUX returned 1.89%/yr vs 1.30%/yr for FMSFX. Their correlation of 0.86 suggests significant overlap in exposure. VBIUX charges 0.04%/yr vs 0.45%/yr for FMSFX.

Performance

VBIUX vs. FMSFX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Intermediate-Term Bond Index Fund Institutional Plus (VBIUX) and Fidelity Mortgage Securities Fund (FMSFX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, VBIUX achieves a -0.04% return, which is significantly lower than FMSFX's 0.97% return. Over the past 10 years, VBIUX has outperformed FMSFX with an annualized return of 1.89%, while FMSFX has yielded a comparatively lower 1.30% annualized return.

VBIUX

• 1D: 0.00%
• 1M: 0.37%
• YTD: -0.04%
• 6M: -0.25%
• 1Y: 5.09%
• 3Y*: 4.29%
• 5Y*: 0.29%
• 10Y*: 1.89%

FMSFX

• 1D: 0.00%
• 1M: 0.52%
• YTD: 0.97%
• 6M: 1.07%
• 1Y: 6.99%
• 3Y*: 4.46%
• 5Y*: 0.22%
• 10Y*: 1.30%

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

VBIUX vs. FMSFX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VBIUX Vanguard Intermediate-Term Bond Index Fund Institutional Plus	-0.04%	8.60%	1.56%	5.53%	-13.24%	-2.64%	9.83%	10.23%	-0.13%	3.90%
FMSFX Fidelity Mortgage Securities Fund	0.97%	8.29%	1.00%	4.91%	-12.61%	-1.20%	4.41%	6.43%	0.79%	2.35%

Correlation

The correlation between VBIUX and FMSFX 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	0.93
Correlation (10Y) Calculated over the trailing 10-year period	0.88
Correlation (All Time) Calculated using the full available price history since Sep 28, 2011	0.86

The correlation between VBIUX and FMSFX has been stable across timeframes, ranging from 0.86 to 0.95 - a consistent structural relationship.

Return for Risk

VBIUX vs. FMSFX — Risk / Return Rank

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

VBIUX

VBIUX Risk / Return Rank: 18
VBIUX Sharpe Ratio Rank: 19
VBIUX Sortino Ratio Rank: 19
VBIUX Omega Ratio Rank: 18
VBIUX Calmar Ratio Rank: 18
VBIUX Martin Ratio Rank: 16

FMSFX

FMSFX Risk / Return Rank: 39
FMSFX Sharpe Ratio Rank: 37
FMSFX Sortino Ratio Rank: 40
FMSFX Omega Ratio Rank: 37
FMSFX Calmar Ratio Rank: 43
FMSFX Martin Ratio Rank: 38

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.

VBIUX vs. FMSFX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Intermediate-Term Bond Index Fund Institutional Plus (VBIUX) and Fidelity Mortgage Securities Fund (FMSFX). 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.

	VBIUX	FMSFX	Difference
Sharpe ratio Return per unit of total volatility	1.24	1.76	-0.53
Sortino ratio Return per unit of downside risk	1.86	2.66	-0.80
Omega ratio Gain probability vs. loss probability	1.22	1.32	-0.11
Calmar ratio Return relative to maximum drawdown	1.54	2.50	-0.96
Martin ratio Return relative to average drawdown	4.54	8.25	-3.71
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

VBIUX vs. FMSFX - Sharpe Ratio Comparison

The current VBIUX Sharpe Ratio is 1.24, which is comparable to the FMSFX Sharpe Ratio of 1.76. The chart below compares the historical Sharpe Ratios of VBIUX and FMSFX, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Sharpe Ratios by Period

	VBIUX	FMSFX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.24	1.76	-0.53
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.05	0.03	+0.01
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.35	0.25	+0.10
Sharpe Ratio (All Time) Calculated using the full available price history	0.47	1.02	-0.56

Drawdowns

VBIUX vs. FMSFX - Drawdown Comparison

The maximum VBIUX drawdown since its inception was -19.18%, roughly equal to the maximum FMSFX drawdown of -18.81%. Use the drawdown chart below to compare losses from any high point for VBIUX and FMSFX.

Drawdown Indicators

	VBIUX	FMSFX	Difference
Max Drawdown Largest peak-to-trough decline	-19.18%	-18.81%	-0.37%
Max Drawdown (1Y) Largest decline over 1 year	-3.33%	-2.81%	-0.52%
Max Drawdown (3Y) Largest decline over 3 years	-6.05%	-8.04%	+1.99%
Max Drawdown (5Y) Largest decline over 5 years	-18.83%	-18.66%	-0.17%
Max Drawdown (10Y) Largest decline over 10 years	-19.18%	-18.81%	-0.37%
Current Drawdown Current decline from peak	-1.83%	-1.11%	-0.72%
Average Drawdown Average peak-to-trough decline	-4.09%	-1.92%	-2.17%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.12%	0.85%	+0.27%

Volatility

VBIUX vs. FMSFX - Volatility Comparison

The current volatility for Vanguard Intermediate-Term Bond Index Fund Institutional Plus (VBIUX) is 1.37%, while Fidelity Mortgage Securities Fund (FMSFX) has a volatility of 1.49%. This indicates that VBIUX experiences smaller price fluctuations and is considered to be less risky than FMSFX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	VBIUX	FMSFX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.37%	1.49%	-0.12%
Volatility (6M) Calculated over the trailing 6-month period	2.98%	2.80%	+0.18%
Volatility (1Y) Calculated over the trailing 1-year period	4.15%	3.99%	+0.16%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	6.39%	6.79%	-0.40%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	5.38%	5.13%	+0.25%

VBIUX vs. FMSFX - Expense Ratio Comparison

VBIUX has a 0.04% expense ratio, which is lower than FMSFX's 0.45% expense ratio.

Dividends

VBIUX vs. FMSFX - Dividend Comparison

VBIUX's dividend yield for the trailing twelve months is around 4.24%, more than FMSFX's 3.90% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
FMSFX Fidelity Mortgage Securities Fund	3.90%	3.93%	4.12%	3.50%	1.43%	0.62%	2.40%	2.62%	2.57%	2.60%	2.65%	2.05%
VBIUX Vanguard Intermediate-Term Bond Index Fund Institutional Plus	4.24%	4.04%	3.82%	2.59%	2.42%	3.08%	2.95%	2.76%	2.89%	2.77%	3.09%	3.14%

Frequently Asked Questions

Can I hold both VBIUX and FMSFX in my portfolio?

With a correlation of 0.94, VBIUX and FMSFX 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, VBIUX or FMSFX?

FMSFX has higher volatility (1.49%) compared to VBIUX (1.37%). In terms of maximum drawdown, VBIUX dropped -19.18% vs FMSFX's -18.81%.

Which has better risk-adjusted returns?

FMSFX currently has the higher Sharpe Ratio (1.76 vs 1.24), 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.