MUB vs. SUB
MUB (iShares National AMT-Free Muni Bond ETF) and SUB (iShares Short-Term National Muni Bond ETF) are both Municipal Bonds funds from iShares - MUB tracks the S&P National AMT-Free Municipal Bond Index while SUB tracks the ICE Short Maturity AMT-Free US National Municipal Index. Both are passively managed. Over the past 10 years, MUB returned 1.79%/yr vs 1.42%/yr for SUB. Their 0.39 correlation means their historical movements had little consistent relationship. Both charge a 0.07% expense ratio.
Performance
MUB vs. SUB - Performance Comparison
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Returns By Period
In the year-to-date period, MUB achieves a 0.21% return, which is significantly lower than SUB's 0.76% return. Over the past 10 years, MUB has outperformed SUB with an annualized return of 1.79%, while SUB has yielded a comparatively lower 1.42% annualized return.
MUB
- 1D
- -0.11%
- 1M
- -1.73%
- 6M
- -0.48%
- YTD
- 0.21%
- 1Y
- 4.48%
- 3Y*
- 2.86%
- 5Y*
- 0.55%
- 10Y*
- 1.79%
- ALL TIME*
- 3.11%
SUB
- 1D
- 0.01%
- 1M
- -0.15%
- 6M
- 0.19%
- YTD
- 0.76%
- 1Y
- 1.85%
- 3Y*
- 3.00%
- 5Y*
- 1.40%
- 10Y*
- 1.42%
- ALL TIME*
- 1.58%
Liquidity Comparison
| Position | Avg. Volume Value (2W) | Avg. Volume Value (1M) | Avg. Volume Value (3M) |
|---|---|---|---|
| $531.87M | $437.83M | $388.20M | |
| $44.46M | $43.86M | $47.41M |
MUB vs. SUB - Yearly Performance Comparison
| 2026 (YTD) | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | |
|---|---|---|---|---|---|---|---|---|---|---|
MUB iShares National AMT-Free Muni Bond ETF | 0.21% | 3.78% | 1.26% | 5.56% | -7.34% | 1.02% | 5.12% | 7.06% | 0.93% | 4.72% |
SUB iShares Short-Term National Muni Bond ETF | 0.76% | 3.64% | 2.17% | 2.91% | -2.05% | 0.03% | 2.51% | 2.93% | 1.85% | 0.75% |
Correlation
The correlation between MUB and SUB is 0.64, which is moderate. They have sometimes moved together and sometimes differently, sharing some price drivers without tracking each other closely.
| Correlation | |
|---|---|
Correlation (1Y) Focuses on recent behavior, but can change the most. | 0.64 |
Correlation (3Y) Balances recent behavior with more history. | 0.70 |
Correlation (5Y) Shows whether the relationship held over a longer period. | 0.71 |
Correlation (10Y) Provides a long-term view across more market conditions. | 0.60 |
Correlation (All Time) Calculated using the full available price history since Nov 7, 2008 | 0.39 |
Over the past year, MUB and SUB have become more correlated (0.64) than their long-term average of 0.39, meaning their price movements have been converging.
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Return for Risk
MUB vs. SUB — Risk / Return Rank
MUB
SUB
MUB vs. SUB - Risk-Adjusted Trends Comparison
This table presents a comparison of risk-adjusted performance metrics for iShares National AMT-Free Muni Bond ETF (MUB) 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.
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.
| MUB | SUB | Difference | |
|---|---|---|---|
| Sharpe ratioReturn per unit of total volatility | -0.10 | ||
| Sortino ratioReturn per unit of downside risk | -0.10 | ||
| Omega ratioGain probability vs. loss probability | 1.34 | 1.37 | -0.03 |
| Calmar ratioReturn relative to maximum drawdown | 1.80 | 2.50 | -0.70 |
| Martin ratioReturn relative to average drawdown | 5.86 | 6.88 | -1.02 |
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Drawdowns
MUB vs. SUB - Drawdown Comparison
The maximum MUB drawdown since its inception was -13.68%, which is greater than SUB's maximum drawdown of -9.46%. Use the drawdown chart below to compare losses from any high point for MUB and SUB.
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Drawdown Indicators
| MUB | SUB | Difference | |
|---|---|---|---|
Max DrawdownLargest peak-to-trough decline | -13.68% | -9.46% | -4.22% |
Max Drawdown (1Y)Largest decline over 1 year | -2.79% | -0.81% | -1.98% |
Max Drawdown (3Y)Largest decline over 3 years | -4.78% | -1.23% | -3.55% |
Max Drawdown (5Y)Largest decline over 5 years | -11.78% | -4.33% | -7.45% |
Max Drawdown (10Y)Largest decline over 10 years | -13.68% | -9.46% | -4.22% |
Current DrawdownCurrent decline from peak | -1.79% | -0.20% | -1.59% |
Average DrawdownAverage peak-to-trough decline | -2.22% | -0.91% | -1.31% |
Ulcer IndexDepth and duration of drawdowns from previous peaks | 0.86% | 0.29% | +0.57% |
Volatility
MUB vs. SUB - Volatility Comparison
iShares National AMT-Free Muni Bond ETF (MUB) has a higher volatility of 0.96% compared to iShares Short-Term National Muni Bond ETF (SUB) at 0.51%. This indicates that MUB'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.
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Volatility by Period
| MUB | SUB | Difference | |
|---|---|---|---|
Volatility (1M)Calculated over the trailing 1-month period | 0.96% | 0.51% | +0.45% |
Volatility (6M)Calculated over the trailing 6-month period | 2.41% | 0.90% | +1.51% |
Volatility (1Y)Calculated over the trailing 1-year period | 2.98% | 1.12% | +1.86% |
Volatility (5Y)Calculated over the trailing 5-year period, annualized | 4.09% | 1.65% | +2.44% |
Volatility (10Y)Calculated over the trailing 10-year period, annualized | 4.91% | 2.60% | +2.31% |
MUB vs. SUB - Expense Ratio Comparison
Both MUB and SUB have an expense ratio of 0.07%, making them cost-effective options compared to the broader market, where average expense ratios typically range from 0.3% to 0.9%.
Dividends
MUB vs. SUB - Dividend Comparison
MUB's dividend yield for the trailing twelve months is around 3.22%, more than SUB's 2.54% yield.
| Position | TTM | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
MUB iShares National AMT-Free Muni Bond ETF | 2.96% | 3.14% | 3.01% | 2.65% | 2.11% | 1.81% | 2.11% | 2.42% | 2.46% | 2.26% | 2.21% | 2.51% |
SUB iShares Short-Term National Muni Bond ETF | 2.34% | 2.42% | 2.10% | 1.73% | 0.86% | 0.72% | 1.23% | 1.58% | 1.32% | 0.95% | 0.75% | 0.77% |
Frequently Asked Questions
MUB and SUB have a correlation of 0.64, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.
MUB has higher volatility (0.96%) compared to SUB (0.51%). In terms of maximum drawdown, MUB dropped -13.68% vs SUB's -9.46%.
On 10-year performance, MUB leads with 1.79% vs 1.42% for SUB. Both ETFs have the same 0.07% expense ratio. On volatility, SUB has been the lower-risk option at 0.51%. The better choice depends on whether you care most about return, fees, risk, or income.
Over the 10-year period, MUB has performed better with a 1.79% return vs 1.42%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.
MUB and SUB have the same expense ratio: 0.07% per year.
MUB has the higher dividend yield at 2.96%, compared with 2.34% for SUB.
MUB tracks S&P National AMT-Free Municipal Bond Index, while SUB tracks ICE Short Maturity AMT-Free US National Municipal Index.
SUB currently has the higher Sharpe Ratio (1.80 vs 1.69), 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.
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