VCOBX vs. VFIAX

Last updated Jun 4, 2026

VCOBX (Vanguard Core Bond Fund Admiral Shares) and VFIAX (Vanguard 500 Index Fund Admiral Shares) are both mutual funds - VCOBX is a Total Bond Market fund managed by Vanguard, while VFIAX is a S&P 500 fund tracking the S&P 500 Index. Over the past 10 years, VCOBX returned 2.19%/yr vs 15.63%/yr for VFIAX. At a correlation of -0.01, they often move in opposite directions. VCOBX charges 0.10%/yr vs 0.04%/yr for VFIAX.

Performance

VCOBX vs. VFIAX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Core Bond Fund Admiral Shares (VCOBX) and Vanguard 500 Index Fund Admiral Shares (VFIAX). 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 lower than VFIAX's 11.69% return. Over the past 10 years, VCOBX has underperformed VFIAX with an annualized return of 2.19%, while VFIAX has yielded a comparatively higher 15.63% 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%

VFIAX

• 1D: 0.13%
• 1M: 5.80%
• YTD: 11.69%
• 6M: 11.73%
• 1Y: 28.95%
• 3Y*: 22.72%
• 5Y*: 14.24%
• 10Y*: 15.63%

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

VCOBX vs. VFIAX - 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%
VFIAX Vanguard 500 Index Fund Admiral Shares	11.69%	17.83%	24.97%	26.24%	-18.16%	28.65%	18.32%	31.46%	-4.45%	21.78%

Correlation

The correlation between VCOBX and VFIAX is 0.30, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.30
Correlation (3Y) Calculated over the trailing 3-year period	0.22
Correlation (5Y) Calculated over the trailing 5-year period	0.15
Correlation (10Y) Calculated over the trailing 10-year period	-0.00
Correlation (All Time) Calculated using the full available price history since Mar 31, 2016	-0.01

The correlation between VCOBX and VFIAX shifts across timeframes, from -0.01 (all time) to 0.30 (1 year), reflecting how their relationship changes across market environments.

VCOBX vs. VFIAX - Sectors Allocation Comparison

Sectors	VCOBX	VFIAX
Financial Services	1.0%	11.6%
Technology	0.1%	35.7%
Energy	0.0%	3.5%
Real Estate	0.0%	1.9%
Basic Materials	-	1.8%
Communication Services	-	11.3%
Consumer Cyclical	-	10.2%
Consumer Defensive	-	4.9%
Healthcare	-	8.5%
Industrials	-	8.3%
Utilities	-	2.4%

Return for Risk

VCOBX vs. VFIAX — 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

VFIAX

VFIAX Risk / Return Rank: 73
VFIAX Sharpe Ratio Rank: 75
VFIAX Sortino Ratio Rank: 67
VFIAX Omega Ratio Rank: 67
VFIAX Calmar Ratio Rank: 74
VFIAX Martin Ratio Rank: 83

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. VFIAX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Core Bond Fund Admiral Shares (VCOBX) and Vanguard 500 Index Fund Admiral Shares (VFIAX). 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	VFIAX	Difference
Sharpe ratio Return per unit of total volatility	1.57	2.52	-0.95
Sortino ratio Return per unit of downside risk	2.34	3.42	-1.08
Omega ratio Gain probability vs. loss probability	1.29	1.46	-0.17
Calmar ratio Return relative to maximum drawdown	2.20	3.35	-1.15
Martin ratio Return relative to average drawdown	6.56	15.66	-9.10
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. VFIAX - Sharpe Ratio Comparison

The current VCOBX Sharpe Ratio is 1.57, which is lower than the VFIAX Sharpe Ratio of 2.52. The chart below compares the historical Sharpe Ratios of VCOBX and VFIAX, 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	VFIAX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.57	2.52	-0.95
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.11	0.85	-0.73
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.46	0.87	-0.41
Sharpe Ratio (All Time) Calculated using the full available price history	0.48	0.47	+0.02

Drawdowns

VCOBX vs. VFIAX - Drawdown Comparison

The maximum VCOBX drawdown since its inception was -18.14%, smaller than the maximum VFIAX drawdown of -55.20%. Use the drawdown chart below to compare losses from any high point for VCOBX and VFIAX.

Drawdown Indicators

	VCOBX	VFIAX	Difference
Max Drawdown Largest peak-to-trough decline	-18.14%	-55.20%	+37.06%
Max Drawdown (1Y) Largest decline over 1 year	-2.62%	-8.90%	+6.28%
Max Drawdown (3Y) Largest decline over 3 years	-5.63%	-18.75%	+13.12%
Max Drawdown (5Y) Largest decline over 5 years	-18.03%	-24.53%	+6.50%
Max Drawdown (10Y) Largest decline over 10 years	-18.14%	-33.83%	+15.69%
Current Drawdown Current decline from peak	-1.25%	0.00%	-1.25%
Average Drawdown Average peak-to-trough decline	-4.18%	-9.40%	+5.22%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.88%	1.90%	-1.02%

Volatility

VCOBX vs. VFIAX - Volatility Comparison

The current volatility for Vanguard Core Bond Fund Admiral Shares (VCOBX) is 1.33%, while Vanguard 500 Index Fund Admiral Shares (VFIAX) has a volatility of 2.82%. This indicates that VCOBX experiences smaller price fluctuations and is considered to be less risky than VFIAX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	VCOBX	VFIAX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.33%	2.82%	-1.49%
Volatility (6M) Calculated over the trailing 6-month period	2.66%	8.98%	-6.32%
Volatility (1Y) Calculated over the trailing 1-year period	3.68%	11.86%	-8.18%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	5.78%	16.90%	-11.12%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	4.76%	18.07%	-13.31%

VCOBX vs. VFIAX - Expense Ratio Comparison

VCOBX has a 0.10% expense ratio, which is higher than VFIAX's 0.04% 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. VFIAX - Dividend Comparison

VCOBX's dividend yield for the trailing twelve months is around 4.73%, more than VFIAX's 1.01% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
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%
VFIAX Vanguard 500 Index Fund Admiral Shares	1.01%	1.12%	1.24%	1.45%	1.68%	1.24%	1.53%	1.87%	2.05%	1.78%	2.02%	2.10%

Frequently Asked Questions

Can I hold both VCOBX and VFIAX in my portfolio?

VCOBX and VFIAX have a correlation of 0.30, 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 VFIAX?

VFIAX has higher volatility (2.82%) compared to VCOBX (1.33%). In terms of maximum drawdown, VCOBX dropped -18.14% vs VFIAX's -55.20%.

Which has better risk-adjusted returns?

VFIAX currently has the higher Sharpe Ratio (2.52 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.