SUB vs. ZMUN

Last updated Jun 25, 2026

SUB (iShares Short-Term National Muni Bond ETF) and ZMUN (F/m Ultrashort Tax-Free Municipal ETF) are both Municipal Bonds funds - SUB tracks the ICE Short Maturity AMT-Free US National Municipal Index - Benchmark TR Gross while ZMUN tracks the Bloomberg Municipal Bond Currently Callable Index. Both are passively managed. At a 0.30 correlation, their price movements are largely independent. SUB charges 0.07%/yr vs 0.30%/yr for ZMUN.

Performance

SUB vs. ZMUN - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in iShares Short-Term National Muni Bond ETF (SUB) and F/m Ultrashort Tax-Free Municipal ETF (ZMUN). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, SUB achieves a 0.78% return, which is significantly lower than ZMUN's 1.81% return.

SUB

• 1D: -0.02%
• 1M: 0.37%
• YTD: 0.78%
• 6M: 0.88%
• 1Y: 2.73%
• 3Y*: 3.03%
• 5Y*: 1.47%
• 10Y*: 1.44%

ZMUN

• 1D: 0.03%
• 1M: 0.34%
• YTD: 1.81%
• 6M: 1.88%
• 1Y: —
• 3Y*: —
• 5Y*: —
• 10Y*: —

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

SUB vs. ZMUN - Yearly Performance Comparison

	2026 (YTD)	2025
SUB iShares Short-Term National Muni Bond ETF	0.78%	0.81%
ZMUN F/m Ultrashort Tax-Free Municipal ETF	1.81%	0.67%

Correlation

The correlation between SUB and ZMUN is 0.30, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (All Time) Calculated using the full available price history since Sep 30, 2025	0.30

Return for Risk

SUB vs. ZMUN — Risk / Return Rank

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

SUB

SUB Risk / Return Rank: 82
SUB Sharpe Ratio Rank: 90
SUB Sortino Ratio Rank: 91
SUB Omega Ratio Rank: 93
SUB Calmar Ratio Rank: 74
SUB Martin Ratio Rank: 60

ZMUN

Risk / return metrics aren't available yet — we need at least 12 months of trading data to calculate them.

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.

SUB vs. ZMUN - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for iShares Short-Term National Muni Bond ETF (SUB) and F/m Ultrashort Tax-Free Municipal ETF (ZMUN). 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.

	SUB	ZMUN	Difference
Sharpe ratio: Return per unit of total volatility	2.69	—	—
Sortino ratio: Return per unit of downside risk	3.85	—	—
Omega ratio: Gain probability vs. loss probability	1.58	—	—
Calmar ratio: Return relative to maximum drawdown	3.40	—	—
Martin ratio: Return relative to average drawdown	9.60	—	—

Drawdowns

SUB vs. ZMUN - Drawdown Comparison

The maximum SUB drawdown since its inception was -9.46%, which is greater than ZMUN's maximum drawdown of -0.10%. Use the drawdown chart below to compare losses from any high point for SUB and ZMUN.

Drawdown Indicators

	SUB	ZMUN	Difference
Max Drawdown Largest peak-to-trough decline	-9.46%	-0.10%	-9.36%
Max Drawdown (1Y) Largest decline over 1 year	-0.81%	—	—
Max Drawdown (3Y) Largest decline over 3 years	-1.23%	—	—
Max Drawdown (5Y) Largest decline over 5 years	-4.35%	—	—
Max Drawdown (10Y) Largest decline over 10 years	-9.46%	—	—
Current Drawdown Current decline from peak	-0.15%	0.00%	-0.15%
Average Drawdown Average peak-to-trough decline	-0.91%	-0.01%	-0.90%
Ulcer Index Depth and duration of drawdowns from previous peaks	0.28%	—	—

Volatility

Volatility by Period

	SUB	ZMUN	Difference
Volatility (1M) Calculated over the trailing 1-month period	0.30%	—	—
Volatility (6M) Calculated over the trailing 6-month period	0.81%	—	—
Volatility (1Y) Calculated over the trailing 1-year period	1.02%	0.54%	+0.48%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	1.64%	0.54%	+1.10%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	2.60%	0.54%	+2.06%

SUB vs. ZMUN - Expense Ratio Comparison

SUB has a 0.07% expense ratio, which is lower than ZMUN's 0.30% expense ratio.

Dividends

SUB vs. ZMUN - Dividend Comparison

SUB's dividend yield for the trailing twelve months is around 2.53%, more than ZMUN's 2.28% 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%
ZMUN F/m Ultrashort Tax-Free Municipal ETF	2.28%	0.70%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%	0.00%

Frequently Asked Questions

Can I hold both SUB and ZMUN in my portfolio?

SUB and ZMUN have a correlation of 0.30, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which ETF is better, SUB or ZMUN?

On fees, SUB is cheaper at 0.07% per year. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF is cheaper, SUB or ZMUN?

SUB is cheaper with a 0.07% expense ratio, compared with 0.30% for ZMUN.

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

SUB has the higher dividend yield at 2.53%, compared with 2.28% for ZMUN.

What is the main difference between SUB and ZMUN?

SUB tracks ICE Short Maturity AMT-Free US National Municipal Index - Benchmark TR Gross, while ZMUN tracks Bloomberg Municipal Bond Currently Callable Index. They also come from different issuers: iShares and F/m Investments. Their fees differ too: 0.07% for SUB and 0.30% for ZMUN.