CATF vs. MUB

Last updated Jun 24, 2026

CATF (American Century California Municipal Bond ETF) and MUB (iShares National AMT-Free Muni Bond ETF) are both Municipal Bonds funds. CATF is actively managed, while MUB is passively managed. Over the past year, CATF returned 7.60% vs 6.40% for MUB. Their correlation of 0.82 suggests significant overlap in exposure. CATF charges 0.27%/yr vs 0.07%/yr for MUB.

Performance

CATF vs. MUB - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in American Century California Municipal Bond ETF (CATF) and iShares National AMT-Free Muni Bond ETF (MUB). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, CATF achieves a 2.29% return, which is significantly higher than MUB's 1.48% return.

CATF

• 1D: -0.08%
• 1M: 1.47%
• YTD: 2.29%
• 6M: 2.24%
• 1Y: 7.60%
• 3Y*: —
• 5Y*: —
• 10Y*: —

MUB

• 1D: -0.06%
• 1M: 1.29%
• YTD: 1.48%
• 6M: 1.78%
• 1Y: 6.40%
• 3Y*: 3.19%
• 5Y*: 0.93%
• 10Y*: 1.90%

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

CATF vs. MUB - Yearly Performance Comparison

	2026 (YTD)	2025	2024
CATF American Century California Municipal Bond ETF	2.29%	3.78%	0.62%
MUB iShares National AMT-Free Muni Bond ETF	1.48%	3.78%	0.62%

Correlation

The correlation between CATF and MUB is 0.74, 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	0.74
Correlation (All Time) Calculated using the full available price history since Jul 18, 2024	0.82

The correlation between CATF and MUB has been stable across timeframes, ranging from 0.74 to 0.82 - a consistent structural relationship.

Return for Risk

CATF vs. MUB — Risk / Return Rank

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

CATF

CATF Risk / Return Rank: 77
CATF Sharpe Ratio Rank: 85
CATF Sortino Ratio Rank: 90
CATF Omega Ratio Rank: 90
CATF Calmar Ratio Rank: 61
CATF Martin Ratio Rank: 59

MUB

MUB Risk / Return Rank: 66
MUB Sharpe Ratio Rank: 73
MUB Sortino Ratio Rank: 77
MUB Omega Ratio Rank: 82
MUB Calmar Ratio Rank: 48
MUB Martin Ratio Rank: 49

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.

CATF vs. MUB - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for American Century California Municipal Bond ETF (CATF) and iShares National AMT-Free Muni Bond ETF (MUB). 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.

	CATF	MUB	Difference
Sharpe ratio: Return per unit of total volatility	2.49	2.23	+0.26
Sortino ratio: Return per unit of downside risk	3.78	3.24	+0.53
Omega ratio: Gain probability vs. loss probability	1.52	1.46	+0.06
Calmar ratio: Return relative to maximum drawdown	2.76	2.31	+0.45
Martin ratio: Return relative to average drawdown	9.61	8.02	+1.60

CATF vs. MUB - Sharpe Ratio Comparison

The current CATF Sharpe Ratio is 2.49, which is comparable to the MUB Sharpe Ratio of 2.23. The chart below compares the historical Sharpe Ratios of CATF and MUB, 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

CATF vs. MUB - Drawdown Comparison

The maximum CATF drawdown since its inception was -4.83%, smaller than the maximum MUB drawdown of -13.68%. Use the drawdown chart below to compare losses from any high point for CATF and MUB.

Drawdown Indicators

	CATF	MUB	Difference
Max Drawdown Largest peak-to-trough decline	-4.83%	-13.68%	+8.85%
Max Drawdown (1Y) Largest decline over 1 year	-2.77%	-2.79%	+0.02%
Max Drawdown (3Y) Largest decline over 3 years	—	-5.34%	—
Max Drawdown (5Y) Largest decline over 5 years	—	-11.88%	—
Max Drawdown (10Y) Largest decline over 10 years	—	-13.68%	—
Current Drawdown Current decline from peak	-0.22%	-0.47%	+0.25%
Average Drawdown Average peak-to-trough decline	-1.24%	-2.23%	+0.99%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.79%	0.80%	-0.01%

Volatility

CATF vs. MUB - Volatility Comparison

American Century California Municipal Bond ETF (CATF) and iShares National AMT-Free Muni Bond ETF (MUB) have volatilities of 0.80% and 0.77%, respectively, indicating that both stocks experience similar levels of price fluctuations. This suggests that the risk associated with both stocks, as measured by volatility, is nearly the same. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	CATF	MUB	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.80%	0.77%	+0.03%
Volatility (6M) Calculated over the trailing 6-month period	2.22%	2.27%	-0.05%
Volatility (1Y) Calculated over the trailing 1-year period	3.07%	2.88%	+0.19%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	4.28%	4.07%	+0.21%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	4.28%	4.92%	-0.64%

CATF vs. MUB - Expense Ratio Comparison

CATF has a 0.27% expense ratio, which is higher than MUB's 0.07% expense ratio. However, both funds are considered low-cost compared to the broader market, where average expense ratios usually range from 0.3% to 0.9%.

Dividends

CATF vs. MUB - Dividend Comparison

CATF's dividend yield for the trailing twelve months is around 3.49%, more than MUB's 3.17% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
CATF American Century California Municipal Bond ETF	3.49%	3.40%	1.32%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%
MUB iShares National AMT-Free Muni Bond ETF	3.17%	3.14%	3.01%	2.65%	2.11%	1.81%	2.11%	2.42%	2.46%	2.26%	2.21%	2.51%

Frequently Asked Questions

Can I hold both CATF and MUB in my portfolio?

CATF and MUB have a correlation of 0.74, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, CATF or MUB?

CATF has higher volatility (0.80%) compared to MUB (0.77%). In terms of maximum drawdown, CATF dropped -4.83% vs MUB's -13.68%.

Which ETF is better, CATF or MUB?

On 1-year performance, CATF leads with 7.60% vs 6.40% for MUB. On fees, MUB is cheaper at 0.07% per year. Their volatility is very similar. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF has performed better, CATF or MUB?

Over the 1-year period, CATF has performed better with a 7.60% return vs 6.40%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

Which ETF is cheaper, CATF or MUB?

MUB is cheaper with a 0.07% expense ratio, compared with 0.27% for CATF.

Which ETF pays a higher dividend yield, CATF or MUB?

CATF has the higher dividend yield at 3.49%, compared with 3.17% for MUB.

What is the main difference between CATF and MUB?

They also come from different issuers: American Century and iShares. Their fees differ too: 0.27% for CATF and 0.07% for MUB.

Which has better risk-adjusted returns?

CATF currently has the higher Sharpe Ratio (2.49 vs 2.23), 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.