VCOBX vs. VUBFX

Last updated Jun 5, 2026

VCOBX (Vanguard Core Bond Fund Admiral Shares) and VUBFX (Vanguard Ultra-Short-Term Bond Fund Investor Shares) are both Total Bond Market funds from Vanguard. Over the past 10 years, VCOBX returned 2.17%/yr vs 2.61%/yr for VUBFX. At a 0.41 correlation, their price movements are largely independent. VCOBX charges 0.10%/yr vs 0.20%/yr for VUBFX.

Performance

VCOBX vs. VUBFX - Performance Comparison

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

Returns By Period

In the year-to-date period, VCOBX achieves a 0.43% return, which is significantly lower than VUBFX's 1.37% return. Over the past 10 years, VCOBX has underperformed VUBFX with an annualized return of 2.17%, while VUBFX has yielded a comparatively higher 2.61% annualized return.

VCOBX

• 1D: -0.17%
• 1M: 0.16%
• YTD: 0.43%
• 6M: 0.52%
• 1Y: 4.91%
• 3Y*: 4.84%
• 5Y*: 0.55%
• 10Y*: 2.17%

VUBFX

• 1D: 0.00%
• 1M: 0.35%
• YTD: 1.37%
• 6M: 1.75%
• 1Y: 4.30%
• 3Y*: 5.33%
• 5Y*: 3.40%
• 10Y*: 2.61%

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

VCOBX vs. VUBFX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VCOBX Vanguard Core Bond Fund Admiral Shares	0.43%	7.73%	2.21%	6.39%	-13.13%	-1.51%	10.41%	9.64%	-0.85%	3.89%
VUBFX Vanguard Ultra-Short-Term Bond Fund Investor Shares	1.37%	5.04%	5.99%	5.43%	-0.53%	0.03%	1.95%	3.34%	1.94%	1.23%

Correlation

The correlation between VCOBX and VUBFX is 0.39, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.39
Correlation (3Y) Calculated over the trailing 3-year period	0.49
Correlation (5Y) Calculated over the trailing 5-year period	0.52
Correlation (10Y) Calculated over the trailing 10-year period	0.41
Correlation (All Time) Calculated using the full available price history since Mar 31, 2016	0.41

The correlation between VCOBX and VUBFX shifts across timeframes, from 0.39 (1 year) to 0.52 (5 years), reflecting how their relationship changes across market environments.

VCOBX vs. VUBFX - Sectors Allocation Comparison

Sectors	VCOBX	VUBFX
Financial Services	1.0%	100.0%
Technology	0.1%	-
Energy	0.0%	-
Real Estate	0.0%	-
Basic Materials	-	-
Communication Services	-	-
Consumer Cyclical	-	-
Consumer Defensive	-	-
Healthcare	-	-
Industrials	-	-
Utilities	-	-

Return for Risk

VCOBX vs. VUBFX — Risk / Return Rank

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

VCOBX

VCOBX Risk / Return Rank: 28
VCOBX Sharpe Ratio Rank: 28
VCOBX Sortino Ratio Rank: 29
VCOBX Omega Ratio Rank: 27
VCOBX Calmar Ratio Rank: 33
VCOBX Martin Ratio Rank: 26

VUBFX

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

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.

VCOBX vs. VUBFX - Risk-Adjusted Trends Comparison

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

	VCOBX	VUBFX	Difference
Sharpe ratio: Return per unit of total volatility	1.52	5.71	-4.19
Sortino ratio: Return per unit of downside risk	2.26	12.83	-10.57
Omega ratio: Gain probability vs. loss probability	1.27	4.52	-3.25
Calmar ratio: Return relative to maximum drawdown	2.13	14.79	-12.65
Martin ratio: Return relative to average drawdown	6.33	83.04	-76.72
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

VCOBX vs. VUBFX - Sharpe Ratio Comparison

The current VCOBX Sharpe Ratio is 1.52, which is lower than the VUBFX Sharpe Ratio of 5.71. The chart below compares the historical Sharpe Ratios of VCOBX and VUBFX, 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

	VCOBX	VUBFX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.52	5.71	-4.19
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.10	3.47	-3.38
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.46	3.14	-2.69
Sharpe Ratio (All Time) Calculated using the full available price history	0.48	3.11	-2.63

Drawdowns

VCOBX vs. VUBFX - Drawdown Comparison

The maximum VCOBX drawdown since its inception was -18.14%, which is greater than VUBFX's maximum drawdown of -1.86%. Use the drawdown chart below to compare losses from any high point for VCOBX and VUBFX.

Drawdown Indicators

	VCOBX	VUBFX	Difference
Max Drawdown Largest peak-to-trough decline	-18.14%	-1.86%	-16.28%
Max Drawdown (1Y) Largest decline over 1 year	-2.62%	-0.30%	-2.32%
Max Drawdown (3Y) Largest decline over 3 years	-5.63%	-0.30%	-5.33%
Max Drawdown (5Y) Largest decline over 5 years	-18.03%	-1.86%	-16.17%
Max Drawdown (10Y) Largest decline over 10 years	-18.14%	-1.86%	-16.28%
Current Drawdown Current decline from peak	-1.41%	0.00%	-1.41%
Average Drawdown Average peak-to-trough decline	-4.18%	-0.17%	-4.01%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.88%	0.05%	+0.83%

Volatility

VCOBX vs. VUBFX - Volatility Comparison

Vanguard Core Bond Fund Admiral Shares (VCOBX) has a higher volatility of 1.29% compared to Vanguard Ultra-Short-Term Bond Fund Investor Shares (VUBFX) at 0.17%. This indicates that VCOBX's price experiences larger fluctuations and is considered to be riskier than VUBFX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	VCOBX	VUBFX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.29%	0.17%	+1.12%
Volatility (6M) Calculated over the trailing 6-month period	2.63%	0.54%	+2.09%
Volatility (1Y) Calculated over the trailing 1-year period	3.67%	0.77%	+2.90%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	5.78%	0.98%	+4.80%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	4.76%	0.83%	+3.93%

VCOBX vs. VUBFX - Expense Ratio Comparison

VCOBX has a 0.10% expense ratio, which is lower than VUBFX's 0.20% expense ratio. Despite the difference, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

Dividends

VCOBX vs. VUBFX - Dividend Comparison

VCOBX's dividend yield for the trailing twelve months is around 4.74%, more than VUBFX's 4.42% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016
VCOBX Vanguard Core Bond Fund Admiral Shares	4.74%	4.80%	5.04%	4.44%	3.01%	1.23%	3.09%	3.08%	3.10%	2.20%	2.29%
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 VCOBX and VUBFX in my portfolio?

VCOBX and VUBFX have a correlation of 0.39, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, VCOBX or VUBFX?

VCOBX has higher volatility (1.29%) compared to VUBFX (0.17%). In terms of maximum drawdown, VCOBX dropped -18.14% vs VUBFX's -1.86%.

Which has better risk-adjusted returns?

VUBFX currently has the higher Sharpe Ratio (5.71 vs 1.52), 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.