OWCAX vs. OWMBX

Last updated Jun 4, 2026

OWCAX (Old Westbury California Municipal Bond Fund) and OWMBX (Old Westbury Municipal Bond Fund) are both Municipal Bonds funds from Old Westbury. Over the past 5 years, OWCAX returned 0.95%/yr vs 0.65%/yr for OWMBX. Their correlation of 0.84 suggests significant overlap in exposure. Both charge a 0.57% expense ratio.

Performance

OWCAX vs. OWMBX - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in Old Westbury California Municipal Bond Fund (OWCAX) and Old Westbury Municipal Bond Fund (OWMBX). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, OWCAX achieves a 0.09% return, which is significantly lower than OWMBX's 0.37% return.

OWCAX

• 1D: 0.10%
• 1M: 0.31%
• YTD: 0.09%
• 6M: 0.34%
• 1Y: 4.63%
• 3Y*: 3.00%
• 5Y*: 0.95%
• 10Y*: —

OWMBX

• 1D: 0.09%
• 1M: 0.35%
• YTD: 0.37%
• 6M: 0.67%
• 1Y: 4.46%
• 3Y*: 2.73%
• 5Y*: 0.65%
• 10Y*: 1.42%

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

OWCAX vs. OWMBX - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018
OWCAX Old Westbury California Municipal Bond Fund	0.09%	5.14%	0.32%	4.75%	-5.15%	-0.62%	3.91%	4.94%	0.77%
OWMBX Old Westbury Municipal Bond Fund	0.37%	4.29%	0.43%	4.03%	-5.39%	-0.63%	5.01%	5.58%	1.03%

Correlation

The correlation between OWCAX and OWMBX is 0.76, 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	0.76
Correlation (3Y) Calculated over the trailing 3-year period	0.86
Correlation (5Y) Calculated over the trailing 5-year period	0.87
Correlation (All Time) Calculated using the full available price history since Dec 4, 2018	0.84

The correlation between OWCAX and OWMBX shifts across timeframes, from 0.76 (1 year) to 0.87 (5 years), reflecting how their relationship changes across market environments.

Return for Risk

OWCAX vs. OWMBX — Risk / Return Rank

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

OWCAX

OWCAX Risk / Return Rank: 61
OWCAX Sharpe Ratio Rank: 81
OWCAX Sortino Ratio Rank: 84
OWCAX Omega Ratio Rank: 92
OWCAX Calmar Ratio Rank: 28
OWCAX Martin Ratio Rank: 20

OWMBX

OWMBX Risk / Return Rank: 62
OWMBX Sharpe Ratio Rank: 81
OWMBX Sortino Ratio Rank: 82
OWMBX Omega Ratio Rank: 93
OWMBX Calmar Ratio Rank: 31
OWMBX Martin Ratio Rank: 23

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.

OWCAX vs. OWMBX - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for Old Westbury California Municipal Bond Fund (OWCAX) and Old Westbury Municipal Bond Fund (OWMBX). 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.

	OWCAX	OWMBX	Difference
Sharpe ratio Return per unit of total volatility	2.64	2.64	0.00
Sortino ratio Return per unit of downside risk	4.00	3.88	+0.12
Omega ratio Gain probability vs. loss probability	1.71	1.72	-0.01
Calmar ratio Return relative to maximum drawdown	2.00	2.07	-0.07
Martin ratio Return relative to average drawdown	5.29	5.93	-0.63
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

OWCAX vs. OWMBX - Sharpe Ratio Comparison

The current OWCAX Sharpe Ratio is 2.64, which is comparable to the OWMBX Sharpe Ratio of 2.64. The chart below compares the historical Sharpe Ratios of OWCAX and OWMBX, 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

	OWCAX	OWMBX	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.64	2.64	0.00
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.31	0.22	+0.10
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	—	0.47	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.58	1.05	-0.47

Drawdowns

OWCAX vs. OWMBX - Drawdown Comparison

The maximum OWCAX drawdown since its inception was -8.91%, smaller than the maximum OWMBX drawdown of -9.54%. Use the drawdown chart below to compare losses from any high point for OWCAX and OWMBX.

Drawdown Indicators

	OWCAX	OWMBX	Difference
Max Drawdown Largest peak-to-trough decline	-8.91%	-9.54%	+0.63%
Max Drawdown (1Y) Largest decline over 1 year	-2.62%	-2.45%	-0.17%
Max Drawdown (3Y) Largest decline over 3 years	-3.41%	-3.81%	+0.40%
Max Drawdown (5Y) Largest decline over 5 years	-8.91%	-9.37%	+0.46%
Max Drawdown (10Y) Largest decline over 10 years	—	-9.44%	—
Current Drawdown Current decline from peak	-1.61%	-1.25%	-0.36%
Average Drawdown Average peak-to-trough decline	-1.99%	-1.64%	-0.35%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.93%	0.80%	+0.13%

Volatility

OWCAX vs. OWMBX - Volatility Comparison

Old Westbury California Municipal Bond Fund (OWCAX) has a higher volatility of 0.70% compared to Old Westbury Municipal Bond Fund (OWMBX) at 0.65%. This indicates that OWCAX's price experiences larger fluctuations and is considered to be riskier than OWMBX based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	OWCAX	OWMBX	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.70%	0.65%	+0.05%
Volatility (6M) Calculated over the trailing 6-month period	1.49%	1.44%	+0.05%
Volatility (1Y) Calculated over the trailing 1-year period	1.99%	1.92%	+0.07%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	3.16%	3.11%	+0.05%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	3.22%	3.04%	+0.18%

OWCAX vs. OWMBX - Expense Ratio Comparison

Both OWCAX and OWMBX have an expense ratio of 0.57%.

Dividends

OWCAX vs. OWMBX - Dividend Comparison

OWCAX's dividend yield for the trailing twelve months is around 2.56%, less than OWMBX's 2.61% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
OWCAX Old Westbury California Municipal Bond Fund	2.56%	3.23%	2.61%	2.35%	1.33%	1.89%	1.83%	1.97%	0.07%	0.00%	0.00%	0.00%
OWMBX Old Westbury Municipal Bond Fund	2.61%	2.61%	2.54%	2.01%	1.15%	2.06%	2.55%	1.68%	1.45%	1.18%	1.61%	1.40%

Frequently Asked Questions

Can I hold both OWCAX and OWMBX in my portfolio?

OWCAX and OWMBX have a correlation of 0.76, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, OWCAX or OWMBX?

OWCAX has higher volatility (0.70%) compared to OWMBX (0.65%). In terms of maximum drawdown, OWCAX dropped -8.91% vs OWMBX's -9.54%.

Which has better risk-adjusted returns?

OWCAX currently has the higher Sharpe Ratio (2.64 vs 2.64), 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.