TAXF vs. SUB

Last updated Jun 4, 2026

TAXF (American Century Diversified Municipal Bond ETF) and SUB (iShares Short-Term National Muni Bond ETF) are both Municipal Bonds funds. TAXF is actively managed, while SUB is passively managed. Over the past 5 years, TAXF returned 1.07%/yr vs 1.46%/yr for SUB. A 0.58 correlation means they provide meaningful diversification when combined. TAXF charges 0.29%/yr vs 0.07%/yr for SUB.

Performance

TAXF vs. SUB - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Century Diversified Municipal Bond ETF (TAXF) and iShares Short-Term National Muni Bond ETF (SUB). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, TAXF achieves a 1.96% return, which is significantly higher than SUB's 0.79% return.

TAXF

• 1D: -0.01%
• 1M: 0.82%
• YTD: 1.96%
• 6M: 2.23%
• 1Y: 8.33%
• 3Y*: 4.23%
• 5Y*: 1.07%
• 10Y*: —

SUB

• 1D: 0.01%
• 1M: 0.32%
• YTD: 0.79%
• 6M: 1.15%
• 1Y: 3.18%
• 3Y*: 3.19%
• 5Y*: 1.46%
• 10Y*: 1.49%

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

TAXF vs. SUB - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018
TAXF American Century Diversified Municipal Bond ETF	1.96%	4.30%	1.74%	7.33%	-9.64%	2.72%	5.55%	8.75%	0.64%
SUB iShares Short-Term National Muni Bond ETF	0.79%	3.64%	2.17%	2.91%	-2.05%	0.03%	2.51%	2.93%	1.02%

Correlation

The correlation between TAXF and SUB is 0.50, 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	0.50
Correlation (3Y) Calculated over the trailing 3-year period	0.63
Correlation (5Y) Calculated over the trailing 5-year period	0.66
Correlation (All Time) Calculated using the full available price history since Sep 13, 2018	0.58

The correlation between TAXF and SUB shifts across timeframes, from 0.50 (1 year) to 0.66 (5 years), reflecting how their relationship changes across market environments.

Return for Risk

TAXF vs. SUB — Risk / Return Rank

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

TAXF

TAXF Risk / Return Rank: 76
TAXF Sharpe Ratio Rank: 83
TAXF Sortino Ratio Rank: 87
TAXF Omega Ratio Rank: 90
TAXF Calmar Ratio Rank: 58
TAXF Martin Ratio Rank: 59

SUB

SUB Risk / Return Rank: 83
SUB Sharpe Ratio Rank: 90
SUB Sortino Ratio Rank: 92
SUB Omega Ratio Rank: 95
SUB Calmar Ratio Rank: 77
SUB Martin Ratio Rank: 62

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.

TAXF vs. SUB - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century Diversified Municipal Bond ETF (TAXF) and iShares Short-Term National Muni Bond ETF (SUB). 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.

	TAXF	SUB	Difference
Sharpe ratio: Return per unit of total volatility	2.74	3.20	-0.46
Sortino ratio: Return per unit of downside risk	3.97	4.64	-0.67
Omega ratio: Gain probability vs. loss probability	1.59	1.72	-0.12
Calmar ratio: Return relative to maximum drawdown	2.86	3.97	-1.11
Martin ratio: Return relative to average drawdown	10.30	11.24	-0.93
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

TAXF vs. SUB - Sharpe Ratio Comparison

The current TAXF Sharpe Ratio is 2.74, which is comparable to the SUB Sharpe Ratio of 3.20. The chart below compares the historical Sharpe Ratios of TAXF and SUB, 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

	TAXF	SUB	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	2.74	3.20	-0.46
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	0.26	0.90	-0.64
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	—	0.57	—
Sharpe Ratio (All Time) Calculated using the full available price history	0.62	0.42	+0.20

Drawdowns

TAXF vs. SUB - Drawdown Comparison

The maximum TAXF drawdown since its inception was -13.93%, which is greater than SUB's maximum drawdown of -9.46%. Use the drawdown chart below to compare losses from any high point for TAXF and SUB.

Drawdown Indicators

	TAXF	SUB	Difference
Max Drawdown Largest peak-to-trough decline	-13.93%	-9.46%	-4.47%
Max Drawdown (1Y) Largest decline over 1 year	-2.93%	-0.81%	-2.12%
Max Drawdown (3Y) Largest decline over 3 years	-5.53%	-1.23%	-4.30%
Max Drawdown (5Y) Largest decline over 5 years	-13.93%	-4.35%	-9.58%
Max Drawdown (10Y) Largest decline over 10 years	—	-9.46%	—
Current Drawdown Current decline from peak	-0.48%	-0.11%	-0.37%
Average Drawdown Average peak-to-trough decline	-3.14%	-0.92%	-2.22%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.81%	0.28%	+0.53%

Volatility

TAXF vs. SUB - Volatility Comparison

American Century Diversified Municipal Bond ETF (TAXF) has a higher volatility of 0.99% compared to iShares Short-Term National Muni Bond ETF (SUB) at 0.28%. This indicates that TAXF's price experiences larger fluctuations and is considered to be riskier than SUB based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	TAXF	SUB	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.99%	0.28%	+0.71%
Volatility (6M) Calculated over the trailing 6-month period	2.24%	0.79%	+1.45%
Volatility (1Y) Calculated over the trailing 1-year period	3.05%	1.00%	+2.05%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	4.20%	1.64%	+2.56%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	4.65%	2.60%	+2.05%

TAXF vs. SUB - Expense Ratio Comparison

TAXF has a 0.29% expense ratio, which is higher than SUB's 0.07% expense ratio.

Dividends

TAXF vs. SUB - Dividend Comparison

TAXF's dividend yield for the trailing twelve months is around 3.47%, more than SUB's 2.53% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
SUB iShares Short-Term National Muni Bond ETF	2.53%	2.42%	2.10%	1.73%	0.86%	0.72%	1.23%	1.58%	1.32%	0.95%	0.75%	0.77%
TAXF American Century Diversified Municipal Bond ETF	3.47%	3.68%	3.38%	2.93%	2.05%	1.58%	2.13%	2.64%	0.69%	0.00%	0.00%	0.00%

Frequently Asked Questions

Can I hold both TAXF and SUB in my portfolio?

TAXF and SUB have a correlation of 0.50, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, TAXF or SUB?

TAXF has higher volatility (0.99%) compared to SUB (0.28%). In terms of maximum drawdown, TAXF dropped -13.93% vs SUB's -9.46%.

Which ETF is better, TAXF or SUB?

On 5-year performance, SUB leads with 1.46% vs 1.07% for TAXF. On fees, SUB is cheaper at 0.07% per year. On volatility, SUB has been the lower-risk option at 0.28%. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF has performed better, TAXF or SUB?

Over the 5-year period, SUB has performed better with a 1.46% return vs 1.07%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

Which ETF is cheaper, TAXF or SUB?

SUB is cheaper with a 0.07% expense ratio, compared with 0.29% for TAXF.

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

TAXF has the higher dividend yield at 3.47%, compared with 2.53% for SUB.

What is the main difference between TAXF and SUB?

They also come from different issuers: American Century and iShares. Their fees differ too: 0.29% for TAXF and 0.07% for SUB.

Which has better risk-adjusted returns?

SUB currently has the higher Sharpe Ratio (3.20 vs 2.74), 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.