ZTAX vs. TAXF

Last updated Jun 23, 2026

ZTAX (X-Square Municipal Income Tax Free ETF) and TAXF (American Century Diversified Municipal Bond ETF) are both Municipal Bonds funds. Both are actively managed. Over the past 3 years, ZTAX returned 4.78%/yr vs 3.96%/yr for TAXF. At a 0.04 correlation, their price movements are largely independent. ZTAX charges 1.14%/yr vs 0.29%/yr for TAXF.

Performance

ZTAX vs. TAXF - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in X-Square Municipal Income Tax Free ETF (ZTAX) and American Century Diversified Municipal Bond ETF (TAXF). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, ZTAX achieves a 3.16% return, which is significantly higher than TAXF's 2.22% return.

ZTAX

• 1D: 1.76%
• 1M: 2.70%
• YTD: 3.16%
• 6M: 4.79%
• 1Y: 8.93%
• 3Y*: 4.78%
• 5Y*: —
• 10Y*: —

TAXF

• 1D: 0.00%
• 1M: 1.52%
• YTD: 2.22%
• 6M: 2.30%
• 1Y: 7.55%
• 3Y*: 3.96%
• 5Y*: 1.13%
• 10Y*: —

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

ZTAX vs. TAXF - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023
ZTAX X-Square Municipal Income Tax Free ETF	3.16%	-1.02%	7.98%	3.74%
TAXF American Century Diversified Municipal Bond ETF	2.22%	4.30%	1.74%	4.88%

Correlation

The correlation between ZTAX and TAXF is -0.07, meaning there is essentially no relationship between their price movements. Each responds to its own set of market drivers, making them strong candidates for combining in a diversified portfolio.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	-0.07
Correlation (3Y) Calculated over the trailing 3-year period	0.03
Correlation (All Time) Calculated using the full available price history since May 19, 2023	0.04

The correlation between ZTAX and TAXF shifts across timeframes, from -0.07 (1 year) to 0.04 (all time), reflecting how their relationship changes across market environments.

Return for Risk

ZTAX vs. TAXF — Risk / Return Rank

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

ZTAX

ZTAX Risk / Return Rank: 16
ZTAX Sharpe Ratio Rank: 12
ZTAX Sortino Ratio Rank: 13
ZTAX Omega Ratio Rank: 16
ZTAX Calmar Ratio Rank: 19
ZTAX Martin Ratio Rank: 18

TAXF

TAXF Risk / Return Rank: 73
TAXF Sharpe Ratio Rank: 82
TAXF Sortino Ratio Rank: 86
TAXF Omega Ratio Rank: 90
TAXF Calmar Ratio Rank: 54
TAXF Martin Ratio Rank: 55

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.

ZTAX vs. TAXF - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for X-Square Municipal Income Tax Free ETF (ZTAX) and American Century Diversified Municipal Bond ETF (TAXF). 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.

	ZTAX	TAXF	Difference
Sharpe ratio: Return per unit of total volatility	0.28	2.53	-2.25
Sortino ratio: Return per unit of downside risk	0.63	3.67	-3.04
Omega ratio: Gain probability vs. loss probability	1.11	1.54	-0.43
Calmar ratio: Return relative to maximum drawdown	0.82	2.59	-1.78
Martin ratio: Return relative to average drawdown	2.00	9.29	-7.29

ZTAX vs. TAXF - Sharpe Ratio Comparison

The current ZTAX Sharpe Ratio is 0.28, which is lower than the TAXF Sharpe Ratio of 2.53. The chart below compares the historical Sharpe Ratios of ZTAX and TAXF, 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

ZTAX vs. TAXF - Drawdown Comparison

The maximum ZTAX drawdown since its inception was -15.33%, which is greater than TAXF's maximum drawdown of -13.93%. Use the drawdown chart below to compare losses from any high point for ZTAX and TAXF.

Drawdown Indicators

	ZTAX	TAXF	Difference
Max Drawdown Largest peak-to-trough decline	-15.33%	-13.93%	-1.40%
Max Drawdown (1Y) Largest decline over 1 year	-10.99%	-2.93%	-8.06%
Max Drawdown (3Y) Largest decline over 3 years	-15.33%	-5.53%	-9.80%
Max Drawdown (5Y) Largest decline over 5 years	—	-13.93%	—
Current Drawdown Current decline from peak	-9.42%	-0.22%	-9.20%
Average Drawdown Average peak-to-trough decline	-6.81%	-3.13%	-3.68%
Ulcer Index Depth and duration of drawdowns from previous peaks	4.48%	0.81%	+3.67%

Volatility

ZTAX vs. TAXF - Volatility Comparison

X-Square Municipal Income Tax Free ETF (ZTAX) has a higher volatility of 19.58% compared to American Century Diversified Municipal Bond ETF (TAXF) at 0.75%. This indicates that ZTAX's price experiences larger fluctuations and is considered to be riskier than TAXF based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	ZTAX	TAXF	Difference
Volatility (1M) Calculated over the trailing 1-month period	19.58%	0.75%	+18.83%
Volatility (6M) Calculated over the trailing 6-month period	28.53%	2.28%	+26.25%
Volatility (1Y) Calculated over the trailing 1-year period	32.37%	3.00%	+29.37%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	28.92%	4.20%	+24.72%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	28.92%	4.64%	+24.28%

ZTAX vs. TAXF - Expense Ratio Comparison

ZTAX has a 1.14% expense ratio, which is higher than TAXF's 0.29% expense ratio.

Dividends

ZTAX vs. TAXF - Dividend Comparison

ZTAX's dividend yield for the trailing twelve months is around 4.43%, more than TAXF's 3.76% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018
TAXF American Century Diversified Municipal Bond ETF	3.76%	3.68%	3.38%	2.93%	2.05%	1.58%	2.13%	2.64%	0.69%
ZTAX X-Square Municipal Income Tax Free ETF	4.43%	4.58%	4.55%	2.14%	0.00%	0.00%	0.00%	0.00%	0.00%

Frequently Asked Questions

Can I hold both ZTAX and TAXF in my portfolio?

ZTAX and TAXF have a correlation of -0.07, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, ZTAX or TAXF?

ZTAX has higher volatility (19.58%) compared to TAXF (0.75%). In terms of maximum drawdown, ZTAX dropped -15.33% vs TAXF's -13.93%.

Which ETF is better, ZTAX or TAXF?

On 3-year performance, ZTAX leads with 4.78% vs 3.96% for TAXF. On fees, TAXF is cheaper at 0.29% per year. On volatility, TAXF has been the lower-risk option at 0.75%. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF has performed better, ZTAX or TAXF?

Over the 3-year period, ZTAX has performed better with a 4.78% return vs 3.96%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

Which ETF is cheaper, ZTAX or TAXF?

TAXF is cheaper with a 0.29% expense ratio, compared with 1.14% for ZTAX.

Which ETF pays a higher dividend yield, ZTAX or TAXF?

ZTAX has the higher dividend yield at 4.43%, compared with 3.76% for TAXF.

What is the main difference between ZTAX and TAXF?

They also come from different issuers: X-Square and American Century. Their fees differ too: 1.14% for ZTAX and 0.29% for TAXF.

Which has better risk-adjusted returns?

TAXF currently has the higher Sharpe Ratio (2.53 vs 0.28), 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.