WACPX vs. VMBSX

Last updated Jul 17, 2026

WACPX (Western Asset Core Plus Bond Fund Class I) and VMBSX (Vanguard Mortgage-Backed Securities Index Fund Admiral Shares) are both Total Bond Market funds. Over the past 10 years, WACPX returned 1.60%/yr vs 1.83%/yr for VMBSX. A 0.78 correlation means they provide meaningful diversification when combined. WACPX charges 0.45%/yr vs 0.07%/yr for VMBSX.

Performance

WACPX vs. VMBSX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Western Asset Core Plus Bond Fund Class I (WACPX) and Vanguard Mortgage-Backed Securities Index Fund Admiral Shares (VMBSX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, WACPX achieves a -0.01% return, which is significantly lower than VMBSX's 0.90% return. Over the past 10 years, WACPX has underperformed VMBSX with an annualized return of 1.60%, while VMBSX has yielded a comparatively higher 1.83% annualized return.

WACPX

• 1D: 0.22%
• 1M: -0.47%
• 6M: -0.22%
• YTD: -0.01%
• 1Y: 4.40%
• 3Y*: 3.45%
• 5Y*: -1.44%
• 10Y*: 1.60%

VMBSX

• 1D: 0.22%
• 1M: -0.34%
• 6M: 0.42%
• YTD: 0.90%
• 1Y: 5.82%
• 3Y*: 4.62%
• 5Y*: 0.54%
• 10Y*: 1.83%

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

WACPX vs. VMBSX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
WACPX Western Asset Core Plus Bond Fund Class I	-0.01%	7.99%	-0.77%	7.51%	-18.79%	-2.24%	9.42%	12.29%	-1.47%	7.10%
VMBSX Vanguard Mortgage-Backed Securities Index Fund Admiral Shares	0.90%	8.43%	1.76%	4.99%	-11.56%	-1.35%	3.74%	11.47%	0.87%	2.32%

Correlation

The correlation between WACPX and VMBSX is 0.89, 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	0.89
Correlation (3Y) Calculated over the trailing 3-year period	0.92
Correlation (5Y) Calculated over the trailing 5-year period	0.90
Correlation (10Y) Calculated over the trailing 10-year period	0.81
Correlation (All Time) Calculated using the full available price history since Nov 23, 2009	0.78

The correlation between WACPX and VMBSX shifts across timeframes, from 0.78 (all time) to 0.92 (3 years), reflecting how their relationship changes across market environments.

Return for Risk

WACPX vs. VMBSX — Risk / Return Rank

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

WACPX

WACPX Risk / Return Rank: 23
WACPX Sharpe Ratio Rank: 25
WACPX Sortino Ratio Rank: 26
WACPX Omega Ratio Rank: 24
WACPX Calmar Ratio Rank: 20
WACPX Martin Ratio Rank: 19

VMBSX

VMBSX Risk / Return Rank: 49
VMBSX Sharpe Ratio Rank: 50
VMBSX Sortino Ratio Rank: 53
VMBSX Omega Ratio Rank: 50
VMBSX Calmar Ratio Rank: 53
VMBSX Martin Ratio Rank: 40

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.

WACPX vs. VMBSX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Western Asset Core Plus Bond Fund Class I (WACPX) and Vanguard Mortgage-Backed Securities Index Fund Admiral Shares (VMBSX). 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.

	WACPX	VMBSX	Difference
Sharpe ratio: Return per unit of total volatility	1.12	1.61	-0.49
Sortino ratio: Return per unit of downside risk	1.66	2.35	-0.69
Omega ratio: Gain probability vs. loss probability	1.20	1.30	-0.10
Calmar ratio: Return relative to maximum drawdown	1.29	2.28	-0.99
Martin ratio: Return relative to average drawdown	3.64	6.99	-3.36

WACPX vs. VMBSX - Sharpe Ratio Comparison

The current WACPX Sharpe Ratio is 1.12, which is lower than the VMBSX Sharpe Ratio of 1.61. The chart below compares the historical Sharpe Ratios of WACPX and VMBSX, 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

WACPX vs. VMBSX - Drawdown Comparison

The maximum WACPX drawdown since its inception was -25.86%, which is greater than VMBSX's maximum drawdown of -17.44%. Use the drawdown chart below to compare losses from any high point for WACPX and VMBSX.

Drawdown Indicators

	WACPX	VMBSX	Difference
Max Drawdown Largest peak-to-trough decline	-25.86%	-17.44%	-8.42%
Max Drawdown (1Y) Largest decline over 1 year	-3.60%	-2.67%	-0.93%
Max Drawdown (3Y) Largest decline over 3 years	-9.55%	-7.53%	-2.02%
Max Drawdown (5Y) Largest decline over 5 years	-25.46%	-17.12%	-8.34%
Max Drawdown (10Y) Largest decline over 10 years	-25.86%	-17.44%	-8.42%
Current Drawdown Current decline from peak	-8.55%	-1.13%	-7.42%
Average Drawdown Average peak-to-trough decline	-3.63%	-2.47%	-1.16%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.28%	0.87%	+0.41%

Volatility

WACPX vs. VMBSX - Volatility Comparison

The current volatility for Western Asset Core Plus Bond Fund Class I (WACPX) is 1.08%, while Vanguard Mortgage-Backed Securities Index Fund Admiral Shares (VMBSX) has a volatility of 1.27%. This indicates that WACPX experiences smaller price fluctuations and is considered to be less risky than VMBSX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	WACPX	VMBSX	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.08%	1.27%	-0.19%
Volatility (6M) Calculated over the trailing 6-month period	3.26%	2.98%	+0.28%
Volatility (1Y) Calculated over the trailing 1-year period	4.17%	3.80%	+0.37%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	7.41%	6.43%	+0.98%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	6.17%	4.88%	+1.29%

WACPX vs. VMBSX - Expense Ratio Comparison

WACPX has a 0.45% expense ratio, which is higher than VMBSX's 0.07% expense ratio.

Dividends

WACPX vs. VMBSX - Dividend Comparison

WACPX's dividend yield for the trailing twelve months is around 4.82%, more than VMBSX's 4.18% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
VMBSX Vanguard Mortgage-Backed Securities Index Fund Admiral Shares	4.18%	4.18%	4.24%	3.28%	2.31%	0.99%	2.00%	7.48%	2.72%	2.16%	1.98%	2.01%
WACPX Western Asset Core Plus Bond Fund Class I	4.82%	4.70%	4.80%	4.88%	3.46%	2.99%	4.12%	4.98%	4.01%	3.30%	4.77%	3.19%

Frequently Asked Questions

Can I hold both WACPX and VMBSX in my portfolio?

WACPX and VMBSX have a correlation of 0.89, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, WACPX or VMBSX?

VMBSX has higher volatility (1.27%) compared to WACPX (1.08%). In terms of maximum drawdown, WACPX dropped -25.86% vs VMBSX's -17.44%.

Which has better risk-adjusted returns?

VMBSX currently has the higher Sharpe Ratio (1.61 vs 1.12), 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.