VCOBX vs. VBMPX

Last updated Jun 4, 2026

VCOBX (Vanguard Core Bond Fund Admiral Shares) and VBMPX (Vanguard Total Bond Market Index Fund Institutional Plus Shares) are both Total Bond Market funds from Vanguard. Over the past 10 years, VCOBX returned 2.19%/yr vs 1.58%/yr for VBMPX. With a 0.96 correlation, they move nearly in lockstep. VCOBX charges 0.10%/yr vs 0.03%/yr for VBMPX.

Performance

VCOBX vs. VBMPX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Core Bond Fund Admiral Shares (VCOBX) and Vanguard Total Bond Market Index Fund Institutional Plus Shares (VBMPX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, VCOBX achieves a 0.60% return, which is significantly higher than VBMPX's 0.43% return. Over the past 10 years, VCOBX has outperformed VBMPX with an annualized return of 2.19%, while VBMPX has yielded a comparatively lower 1.58% annualized return.

VCOBX

• 1D: 0.00%
• 1M: 0.56%
• YTD: 0.60%
• 6M: 0.47%
• 1Y: 5.73%
• 3Y*: 4.90%
• 5Y*: 0.65%
• 10Y*: 2.19%

VBMPX

• 1D: 0.00%
• 1M: 0.55%
• YTD: 0.43%
• 6M: 0.36%
• 1Y: 5.36%
• 3Y*: 4.06%
• 5Y*: 0.23%
• 10Y*: 1.58%

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

VCOBX vs. VBMPX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VCOBX Vanguard Core Bond Fund Admiral Shares	0.60%	7.73%	2.21%	6.39%	-13.13%	-1.51%	10.41%	9.64%	-0.85%	3.89%
VBMPX Vanguard Total Bond Market Index Fund Institutional Plus Shares	0.43%	7.18%	1.27%	5.75%	-13.14%	-1.95%	7.75%	8.74%	-0.24%	3.58%

Correlation

The correlation between VCOBX and VBMPX is 0.92, 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	0.92
Correlation (3Y) Calculated over the trailing 3-year period	0.96
Correlation (5Y) Calculated over the trailing 5-year period	0.97
Correlation (10Y) Calculated over the trailing 10-year period	0.96
Correlation (All Time) Calculated using the full available price history since Mar 31, 2016	0.96

The correlation between VCOBX and VBMPX has been stable across timeframes, ranging from 0.92 to 0.97 - a consistent structural relationship.

Return for Risk

VCOBX vs. VBMPX — Risk / Return Rank

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

VCOBX

VCOBX Risk / Return Rank: 31
VCOBX Sharpe Ratio Rank: 30
VCOBX Sortino Ratio Rank: 32
VCOBX Omega Ratio Rank: 30
VCOBX Calmar Ratio Rank: 34
VCOBX Martin Ratio Rank: 27

VBMPX

VBMPX Risk / Return Rank: 23
VBMPX Sharpe Ratio Rank: 23
VBMPX Sortino Ratio Rank: 24
VBMPX Omega Ratio Rank: 22
VBMPX Calmar Ratio Rank: 25
VBMPX Martin Ratio Rank: 21

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. VBMPX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Core Bond Fund Admiral Shares (VCOBX) and Vanguard Total Bond Market Index Fund Institutional Plus Shares (VBMPX). 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	VBMPX	Difference
Sharpe ratio Return per unit of total volatility	1.57	1.36	+0.21
Sortino ratio Return per unit of downside risk	2.34	2.05	+0.29
Omega ratio Gain probability vs. loss probability	1.29	1.24	+0.04
Calmar ratio Return relative to maximum drawdown	2.20	1.86	+0.34
Martin ratio Return relative to average drawdown	6.56	5.61	+0.95
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. VBMPX - Sharpe Ratio Comparison

The current VCOBX Sharpe Ratio is 1.57, which is comparable to the VBMPX Sharpe Ratio of 1.36. The chart below compares the historical Sharpe Ratios of VCOBX and VBMPX, 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	VBMPX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.57	1.36	+0.21
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.11	0.04	+0.08
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.46	0.32	+0.14
Sharpe Ratio (All Time) Calculated using the full available price history	0.48	0.52	-0.03

Drawdowns

VCOBX vs. VBMPX - Drawdown Comparison

The maximum VCOBX drawdown since its inception was -18.14%, roughly equal to the maximum VBMPX drawdown of -18.90%. Use the drawdown chart below to compare losses from any high point for VCOBX and VBMPX.

Drawdown Indicators

	VCOBX	VBMPX	Difference
Max Drawdown Largest peak-to-trough decline	-18.14%	-18.90%	+0.76%
Max Drawdown (1Y) Largest decline over 1 year	-2.62%	-2.89%	+0.27%
Max Drawdown (3Y) Largest decline over 3 years	-5.63%	-5.99%	+0.36%
Max Drawdown (5Y) Largest decline over 5 years	-18.03%	-18.12%	+0.09%
Max Drawdown (10Y) Largest decline over 10 years	-18.14%	-18.90%	+0.76%
Current Drawdown Current decline from peak	-1.25%	-2.23%	+0.98%
Average Drawdown Average peak-to-trough decline	-4.18%	-3.53%	-0.65%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.88%	0.96%	-0.08%

Volatility

VCOBX vs. VBMPX - Volatility Comparison

Vanguard Core Bond Fund Admiral Shares (VCOBX) and Vanguard Total Bond Market Index Fund Institutional Plus Shares (VBMPX) have volatilities of 1.33% and 1.38%, 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.

Volatility by Period

	VCOBX	VBMPX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.33%	1.38%	-0.05%
Volatility (6M) Calculated over the trailing 6-month period	2.66%	2.80%	-0.14%
Volatility (1Y) Calculated over the trailing 1-year period	3.68%	3.97%	-0.29%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	5.78%	6.02%	-0.24%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	4.76%	4.98%	-0.22%

VCOBX vs. VBMPX - Expense Ratio Comparison

VCOBX has a 0.10% expense ratio, which is higher than VBMPX'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

VCOBX vs. VBMPX - Dividend Comparison

VCOBX's dividend yield for the trailing twelve months is around 4.73%, more than VBMPX's 4.00% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
VBMPX Vanguard Total Bond Market Index Fund Institutional Plus Shares	4.00%	3.88%	3.69%	3.11%	2.61%	1.81%	2.41%	2.75%	2.58%	2.58%	2.55%	2.85%
VCOBX Vanguard Core Bond Fund Admiral Shares	4.73%	4.80%	5.04%	4.44%	3.01%	1.23%	3.09%	3.08%	3.10%	2.20%	2.29%	0.00%

Frequently Asked Questions

Can I hold both VCOBX and VBMPX in my portfolio?

With a correlation of 0.92, VCOBX and VBMPX 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, VCOBX or VBMPX?

VBMPX has higher volatility (1.38%) compared to VCOBX (1.33%). In terms of maximum drawdown, VCOBX dropped -18.14% vs VBMPX's -18.90%.

Which has better risk-adjusted returns?

VCOBX currently has the higher Sharpe Ratio (1.57 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.