VBISX vs. PONAX

Last updated Jun 13, 2026

VBISX (Vanguard Short-Term Bond Index Fund) and PONAX (PIMCO Income Fund Class A) are both mutual funds - VBISX is a Short-Term Bond fund managed by Vanguard, while PONAX is a Multisector Bonds fund managed by PIMCO. Over the past 10 years, VBISX returned 1.77%/yr vs 4.29%/yr for PONAX. A 0.58 correlation means they provide meaningful diversification when combined. VBISX charges 0.15%/yr vs 1.02%/yr for PONAX.

Performance

VBISX vs. PONAX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Vanguard Short-Term Bond Index Fund (VBISX) and PIMCO Income Fund Class A (PONAX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, VBISX achieves a 0.26% return, which is significantly lower than PONAX's 0.74% return. Over the past 10 years, VBISX has underperformed PONAX with an annualized return of 1.77%, while PONAX has yielded a comparatively higher 4.29% annualized return.

VBISX

• 1D: 0.20%
• 1M: 0.24%
• YTD: 0.26%
• 6M: 0.79%
• 1Y: 3.44%
• 3Y*: 4.18%
• 5Y*: 1.40%
• 10Y*: 1.77%

PONAX

• 1D: 0.56%
• 1M: 0.88%
• YTD: 0.74%
• 6M: 1.58%
• 1Y: 7.05%
• 3Y*: 7.27%
• 5Y*: 3.05%
• 10Y*: 4.29%

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

VBISX vs. PONAX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
VBISX Vanguard Short-Term Bond Index Fund	0.26%	5.67%	3.66%	4.54%	-5.61%	-1.35%	4.63%	4.78%	1.27%	1.10%
PONAX PIMCO Income Fund Class A	0.74%	10.63%	5.02%	8.96%	-9.34%	2.21%	5.40%	7.65%	0.21%	8.19%

Correlation

The correlation between VBISX and PONAX is 0.82, 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	0.82
Correlation (3Y) Calculated over the trailing 3-year period	0.84
Correlation (5Y) Calculated over the trailing 5-year period	0.78
Correlation (10Y) Calculated over the trailing 10-year period	0.64
Correlation (All Time) Calculated using the full available price history since Apr 2, 2007	0.58

Over the past year, VBISX and PONAX have become more correlated (0.82) than their long-term average of 0.58, meaning their price movements have been converging.

Return for Risk

VBISX vs. PONAX — Risk / Return Rank

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

VBISX

VBISX Risk / Return Rank: 55
VBISX Sharpe Ratio Rank: 49
VBISX Sortino Ratio Rank: 69
VBISX Omega Ratio Rank: 59
VBISX Calmar Ratio Rank: 56
VBISX Martin Ratio Rank: 41

PONAX

PONAX Risk / Return Rank: 54
PONAX Sharpe Ratio Rank: 61
PONAX Sortino Ratio Rank: 67
PONAX Omega Ratio Rank: 65
PONAX Calmar Ratio Rank: 42
PONAX Martin Ratio Rank: 37

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.

VBISX vs. PONAX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Vanguard Short-Term Bond Index Fund (VBISX) and PIMCO Income Fund Class A (PONAX). 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.

	VBISX	PONAX	Difference
Sharpe ratio: Return per unit of total volatility	1.64	1.80	-0.16
Sortino ratio: Return per unit of downside risk	2.75	2.68	+0.07
Omega ratio: Gain probability vs. loss probability	1.33	1.35	-0.01
Calmar ratio: Return relative to maximum drawdown	2.37	2.01	+0.36
Martin ratio: Return relative to average drawdown	7.35	6.70	+0.65

VBISX vs. PONAX - Sharpe Ratio Comparison

The current VBISX Sharpe Ratio is 1.64, which is comparable to the PONAX Sharpe Ratio of 1.80. The chart below compares the historical Sharpe Ratios of VBISX and PONAX, 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

VBISX vs. PONAX - Drawdown Comparison

The maximum VBISX drawdown since its inception was -8.79%, smaller than the maximum PONAX drawdown of -13.64%. Use the drawdown chart below to compare losses from any high point for VBISX and PONAX.

Drawdown Indicators

	VBISX	PONAX	Difference
Max Drawdown Largest peak-to-trough decline	-8.79%	-13.64%	+4.85%
Max Drawdown (1Y) Largest decline over 1 year	-1.54%	-3.69%	+2.15%
Max Drawdown (3Y) Largest decline over 3 years	-1.55%	-3.90%	+2.35%
Max Drawdown (5Y) Largest decline over 5 years	-8.72%	-13.64%	+4.92%
Max Drawdown (10Y) Largest decline over 10 years	-8.79%	-13.64%	+4.85%
Current Drawdown Current decline from peak	-0.66%	-1.12%	+0.46%
Average Drawdown Average peak-to-trough decline	-0.87%	-1.79%	+0.92%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.50%	1.10%	-0.60%

Volatility

VBISX vs. PONAX - Volatility Comparison

The current volatility for Vanguard Short-Term Bond Index Fund (VBISX) is 0.70%, while PIMCO Income Fund Class A (PONAX) has a volatility of 1.66%. This indicates that VBISX experiences smaller price fluctuations and is considered to be less risky than PONAX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	VBISX	PONAX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.70%	1.66%	-0.96%
Volatility (6M) Calculated over the trailing 6-month period	1.60%	3.34%	-1.74%
Volatility (1Y) Calculated over the trailing 1-year period	2.23%	4.13%	-1.90%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	2.95%	4.83%	-1.88%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	2.39%	4.22%	-1.83%

VBISX vs. PONAX - Expense Ratio Comparison

VBISX has a 0.15% expense ratio, which is lower than PONAX's 1.02% expense ratio.

Dividends

VBISX vs. PONAX - Dividend Comparison

VBISX's dividend yield for the trailing twelve months is around 3.90%, less than PONAX's 5.43% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
PONAX PIMCO Income Fund Class A	5.43%	5.61%	5.86%	5.86%	4.66%	3.62%	4.48%	5.42%	5.24%	4.97%	5.13%	7.45%
VBISX Vanguard Short-Term Bond Index Fund	3.90%	3.44%	3.29%	2.10%	1.38%	1.16%	1.72%	2.16%	1.92%	1.58%	1.42%	1.34%

Frequently Asked Questions

Can I hold both VBISX and PONAX in my portfolio?

VBISX and PONAX have a correlation of 0.82, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, VBISX or PONAX?

PONAX has higher volatility (1.66%) compared to VBISX (0.70%). In terms of maximum drawdown, VBISX dropped -8.79% vs PONAX's -13.64%.

Which has better risk-adjusted returns?

PONAX currently has the higher Sharpe Ratio (1.80 vs 1.64), 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.