VUBFX vs. FNSOX

Last updated Jun 24, 2026

VUBFX (Vanguard Ultra-Short-Term Bond Fund Investor Shares) and FNSOX (Fidelity Short-Term Bond Index Fund) are both Total Bond Market funds. Over the past 5 years, VUBFX returned 3.42%/yr vs 1.59%/yr for FNSOX. At a 0.48 correlation, their price movements are largely independent. VUBFX charges 0.20%/yr vs 0.03%/yr for FNSOX.

Performance

VUBFX vs. FNSOX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Ultra-Short-Term Bond Fund Investor Shares (VUBFX) and Fidelity Short-Term Bond Index Fund (FNSOX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, VUBFX achieves a 1.47% return, which is significantly higher than FNSOX's 0.07% return.

VUBFX

• 1D: 0.10%
• 1M: 0.25%
• YTD: 1.47%
• 6M: 1.58%
• 1Y: 4.19%
• 3Y*: 5.29%
• 5Y*: 3.42%
• 10Y*: 2.61%

FNSOX

• 1D: -0.10%
• 1M: 0.17%
• YTD: 0.07%
• 6M: 0.42%
• 1Y: 3.05%
• 3Y*: 4.48%
• 5Y*: 1.59%
• 10Y*: —

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

VUBFX vs. FNSOX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VUBFX Vanguard Ultra-Short-Term Bond Fund Investor Shares	1.47%	5.04%	5.99%	5.43%	-0.53%	0.03%	1.95%	3.34%	1.94%	0.10%
FNSOX Fidelity Short-Term Bond Index Fund	0.07%	6.01%	3.90%	4.90%	-5.76%	-1.25%	4.28%	4.95%	1.14%	-0.22%

Correlation

The correlation between VUBFX and FNSOX is 0.38, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.38
Correlation (3Y) Calculated over the trailing 3-year period	0.51
Correlation (5Y) Calculated over the trailing 5-year period	0.58
Correlation (All Time) Calculated using the full available price history since Oct 31, 2017	0.48

The correlation between VUBFX and FNSOX shifts across timeframes, from 0.38 (1 year) to 0.58 (5 years), reflecting how their relationship changes across market environments.

Return for Risk

VUBFX vs. FNSOX — Risk / Return Rank

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

VUBFX

VUBFX Risk / Return Rank: 100
VUBFX Sharpe Ratio Rank: 100
VUBFX Sortino Ratio Rank: 100
VUBFX Omega Ratio Rank: 99
VUBFX Calmar Ratio Rank: 99
VUBFX Martin Ratio Rank: 100

FNSOX

FNSOX Risk / Return Rank: 38
FNSOX Sharpe Ratio Rank: 35
FNSOX Sortino Ratio Rank: 43
FNSOX Omega Ratio Rank: 40
FNSOX Calmar Ratio Rank: 38
FNSOX Martin Ratio Rank: 32

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.

VUBFX vs. FNSOX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Ultra-Short-Term Bond Fund Investor Shares (VUBFX) and Fidelity Short-Term Bond Index Fund (FNSOX). 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.

	VUBFX	FNSOX	Difference
Sharpe ratio: Return per unit of total volatility	5.51	1.57	+3.94
Sortino ratio: Return per unit of downside risk	12.01	2.52	+9.50
Omega ratio: Gain probability vs. loss probability	4.18	1.31	+2.87
Calmar ratio: Return relative to maximum drawdown	14.44	2.22	+12.22
Martin ratio: Return relative to average drawdown	81.08	6.88	+74.20

VUBFX vs. FNSOX - Sharpe Ratio Comparison

The current VUBFX Sharpe Ratio is 5.51, which is higher than the FNSOX Sharpe Ratio of 1.57. The chart below compares the historical Sharpe Ratios of VUBFX and FNSOX, 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

VUBFX vs. FNSOX - Drawdown Comparison

The maximum VUBFX drawdown since its inception was -1.86%, smaller than the maximum FNSOX drawdown of -8.92%. Use the drawdown chart below to compare losses from any high point for VUBFX and FNSOX.

Drawdown Indicators

	VUBFX	FNSOX	Difference
Max Drawdown Largest peak-to-trough decline	-1.86%	-8.92%	+7.06%
Max Drawdown (1Y) Largest decline over 1 year	-0.30%	-1.47%	+1.17%
Max Drawdown (3Y) Largest decline over 3 years	-0.30%	-1.51%	+1.21%
Max Drawdown (5Y) Largest decline over 5 years	-1.86%	-8.77%	+6.91%
Max Drawdown (10Y) Largest decline over 10 years	-1.86%	—	—
Current Drawdown Current decline from peak	-0.00%	-0.90%	+0.90%
Average Drawdown Average peak-to-trough decline	-0.17%	-1.73%	+1.56%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.05%	0.47%	-0.42%

Volatility

VUBFX vs. FNSOX - Volatility Comparison

The current volatility for Vanguard Ultra-Short-Term Bond Fund Investor Shares (VUBFX) is 0.25%, while Fidelity Short-Term Bond Index Fund (FNSOX) has a volatility of 0.71%. This indicates that VUBFX experiences smaller price fluctuations and is considered to be less risky than FNSOX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	VUBFX	FNSOX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.25%	0.71%	-0.46%
Volatility (6M) Calculated over the trailing 6-month period	0.57%	1.56%	-0.99%
Volatility (1Y) Calculated over the trailing 1-year period	0.78%	2.08%	-1.30%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	0.99%	2.90%	-1.91%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	0.84%	2.47%	-1.63%

VUBFX vs. FNSOX - Expense Ratio Comparison

VUBFX has a 0.20% expense ratio, which is higher than FNSOX's 0.03% expense ratio. However, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

Dividends

VUBFX vs. FNSOX - Dividend Comparison

VUBFX's dividend yield for the trailing twelve months is around 4.42%, more than FNSOX's 3.54% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016
FNSOX Fidelity Short-Term Bond Index Fund	3.54%	3.22%	2.80%	1.74%	0.81%	0.80%	1.54%	2.61%	2.04%	0.34%	0.00%
VUBFX Vanguard Ultra-Short-Term Bond Fund Investor Shares	4.42%	4.62%	5.42%	4.06%	1.28%	0.43%	1.52%	2.58%	2.13%	1.43%	0.98%

Frequently Asked Questions

Can I hold both VUBFX and FNSOX in my portfolio?

VUBFX and FNSOX have a correlation of 0.38, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, VUBFX or FNSOX?

FNSOX has higher volatility (0.71%) compared to VUBFX (0.25%). In terms of maximum drawdown, VUBFX dropped -1.86% vs FNSOX's -8.92%.

Which has better risk-adjusted returns?

VUBFX currently has the higher Sharpe Ratio (5.51 vs 1.57), 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.