PTLAX vs. VBISX

Last updated Jun 4, 2026

PTLAX (PIMCO Low Duration Fund Class A) and VBISX (Vanguard Short-Term Bond Index Fund) are both Short-Term Bond funds. Over the past 10 years, PTLAX returned 1.73%/yr vs 1.79%/yr for VBISX. A 0.69 correlation means they provide meaningful diversification when combined. PTLAX charges 0.75%/yr vs 0.15%/yr for VBISX.

Performance

PTLAX vs. VBISX - Performance Comparison

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

Returns By Period

In the year-to-date period, PTLAX achieves a 0.28% return, which is significantly higher than VBISX's 0.26% return. Both investments have delivered pretty close results over the past 10 years, with PTLAX having a 1.73% annualized return and VBISX not far ahead at 1.79%.

PTLAX

• 1D: -0.11%
• 1M: 0.12%
• YTD: 0.28%
• 6M: 0.72%
• 1Y: 3.52%
• 3Y*: 4.50%
• 5Y*: 1.49%
• 10Y*: 1.73%

VBISX

• 1D: 0.00%
• 1M: 0.14%
• YTD: 0.26%
• 6M: 0.50%
• 1Y: 3.64%
• 3Y*: 4.14%
• 5Y*: 1.44%
• 10Y*: 1.79%

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

PTLAX vs. VBISX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
PTLAX PIMCO Low Duration Fund Class A	0.28%	5.27%	4.53%	4.72%	-5.87%	-0.96%	3.11%	4.19%	0.21%	1.50%
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%

Correlation

The correlation between PTLAX and VBISX is 0.80, which is moderate. They share some common price drivers but move independently often enough to provide real diversification benefit when combined.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.80
Correlation (3Y) Calculated over the trailing 3-year period	0.83
Correlation (5Y) Calculated over the trailing 5-year period	0.82
Correlation (10Y) Calculated over the trailing 10-year period	0.75
Correlation (All Time) Calculated using the full available price history since Jul 1, 1996	0.69

The correlation between PTLAX and VBISX shifts across timeframes, from 0.69 (all time) to 0.82 (3 years), reflecting how their relationship changes across market environments.

Return for Risk

PTLAX vs. VBISX — Risk / Return Rank

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

PTLAX

PTLAX Risk / Return Rank: 42
PTLAX Sharpe Ratio Rank: 34
PTLAX Sortino Ratio Rank: 49
PTLAX Omega Ratio Rank: 55
PTLAX Calmar Ratio Rank: 35
PTLAX Martin Ratio Rank: 39

VBISX

VBISX Risk / Return Rank: 37
VBISX Sharpe Ratio Rank: 33
VBISX Sortino Ratio Rank: 43
VBISX Omega Ratio Rank: 39
VBISX Calmar Ratio Rank: 40
VBISX Martin Ratio Rank: 33

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.

PTLAX vs. VBISX - Risk-Adjusted Trends Comparison

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

	PTLAX	VBISX	Difference
Sharpe ratio: Return per unit of total volatility	1.69	1.64	+0.05
Sortino ratio: Return per unit of downside risk	2.94	2.75	+0.19
Omega ratio: Gain probability vs. loss probability	1.41	1.33	+0.08
Calmar ratio: Return relative to maximum drawdown	2.22	2.37	-0.15
Martin ratio: Return relative to average drawdown	8.59	7.61	+0.98
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

PTLAX vs. VBISX - Sharpe Ratio Comparison

The current PTLAX Sharpe Ratio is 1.69, which is comparable to the VBISX Sharpe Ratio of 1.64. The chart below compares the historical Sharpe Ratios of PTLAX and VBISX, 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

	PTLAX	VBISX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.69	1.64	+0.05
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.61	0.49	+0.12
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.84	0.75	+0.09
Sharpe Ratio (All Time) Calculated using the full available price history	1.38	1.34	+0.03

Drawdowns

PTLAX vs. VBISX - Drawdown Comparison

The maximum PTLAX drawdown since its inception was -8.48%, roughly equal to the maximum VBISX drawdown of -8.79%. Use the drawdown chart below to compare losses from any high point for PTLAX and VBISX.

Drawdown Indicators

	PTLAX	VBISX	Difference
Max Drawdown Largest peak-to-trough decline	-8.48%	-8.79%	+0.31%
Max Drawdown (1Y) Largest decline over 1 year	-1.60%	-1.54%	-0.06%
Max Drawdown (3Y) Largest decline over 3 years	-1.60%	-1.55%	-0.05%
Max Drawdown (5Y) Largest decline over 5 years	-8.46%	-8.72%	+0.26%
Max Drawdown (10Y) Largest decline over 10 years	-8.48%	-8.79%	+0.31%
Current Drawdown Current decline from peak	-0.43%	-0.66%	+0.23%
Average Drawdown Average peak-to-trough decline	-0.88%	-0.87%	-0.01%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.41%	0.48%	-0.07%

Volatility

PTLAX vs. VBISX - Volatility Comparison

The current volatility for PIMCO Low Duration Fund Class A (PTLAX) is 0.62%, while Vanguard Short-Term Bond Index Fund (VBISX) has a volatility of 0.69%. This indicates that PTLAX experiences smaller price fluctuations and is considered to be less risky than VBISX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	PTLAX	VBISX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.62%	0.69%	-0.07%
Volatility (6M) Calculated over the trailing 6-month period	1.53%	1.59%	-0.06%
Volatility (1Y) Calculated over the trailing 1-year period	2.10%	2.24%	-0.14%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	2.45%	2.94%	-0.49%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	2.07%	2.38%	-0.31%

PTLAX vs. VBISX - Expense Ratio Comparison

PTLAX has a 0.75% expense ratio, which is higher than VBISX's 0.15% expense ratio.

Dividends

PTLAX vs. VBISX - Dividend Comparison

PTLAX's dividend yield for the trailing twelve months is around 3.92%, which matches VBISX's 3.90% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
PTLAX PIMCO Low Duration Fund Class A	3.92%	3.93%	3.86%	3.48%	1.37%	0.56%	1.53%	3.07%	1.86%	1.39%	1.66%	2.16%
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 PTLAX and VBISX in my portfolio?

PTLAX and VBISX have a correlation of 0.80, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, PTLAX or VBISX?

VBISX has higher volatility (0.69%) compared to PTLAX (0.62%). In terms of maximum drawdown, PTLAX dropped -8.48% vs VBISX's -8.79%.

Which has better risk-adjusted returns?

PTLAX currently has the higher Sharpe Ratio (1.69 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.