IBMT vs. AUSM

Last updated Jul 14, 2026

IBMT (iShares iBonds Dec 2031 Term Muni Bond ETF) and AUSM (Allspring Ultra Short Municipal ETF) are both Municipal Bonds funds. IBMT is passively managed, while AUSM is actively managed. Over the past year, IBMT returned 4.84% vs 2.89% for AUSM. At a 0.08 correlation, their price movements are largely independent. Both charge a 0.18% expense ratio.

Performance

IBMT vs. AUSM - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in iShares iBonds Dec 2031 Term Muni Bond ETF (IBMT) and Allspring Ultra Short Municipal ETF (AUSM). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

The year-to-date returns for both investments are quite close, with IBMT having a 1.28% return and AUSM slightly higher at 1.34%.

IBMT

• 1D: 0.00%
• 1M: 1.30%
• 6M: 0.39%
• YTD: 1.28%
• 1Y: 4.84%
• 3Y*: —
• 5Y*: —
• 10Y*: —

AUSM

• 1D: 0.00%
• 1M: 0.22%
• 6M: 1.16%
• YTD: 1.34%
• 1Y: 2.89%
• 3Y*: —
• 5Y*: —
• 10Y*: —

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

IBMT vs. AUSM - Yearly Performance Comparison

	2026 (YTD)	2025
IBMT iShares iBonds Dec 2031 Term Muni Bond ETF	1.28%	3.40%
AUSM Allspring Ultra Short Municipal ETF	1.34%	1.58%

Correlation

The correlation between IBMT and AUSM is 0.09, 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	0.09
Correlation (All Time) Calculated using the full available price history since Jul 8, 2025	0.08

Return for Risk

IBMT vs. AUSM — Risk / Return Rank

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

IBMT

IBMT Risk / Return Rank: 57
IBMT Sharpe Ratio Rank: 61
IBMT Sortino Ratio Rank: 73
IBMT Omega Ratio Rank: 74
IBMT Calmar Ratio Rank: 38
IBMT Martin Ratio Rank: 37

AUSM

AUSM Risk / Return Rank: 97
AUSM Sharpe Ratio Rank: 98
AUSM Sortino Ratio Rank: 98
AUSM Omega Ratio Rank: 98
AUSM Calmar Ratio Rank: 96
AUSM Martin Ratio Rank: 94

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.

IBMT vs. AUSM - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for iShares iBonds Dec 2031 Term Muni Bond ETF (IBMT) and Allspring Ultra Short Municipal ETF (AUSM). 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.

	IBMT	AUSM	Difference
Sharpe ratio: Return per unit of total volatility	1.62	3.96	-2.33
Sortino ratio: Return per unit of downside risk	2.60	6.86	-4.26
Omega ratio: Gain probability vs. loss probability	1.35	2.26	-0.92
Calmar ratio: Return relative to maximum drawdown	1.57	6.94	-5.37
Martin ratio: Return relative to average drawdown	4.48	20.53	-16.04

IBMT vs. AUSM - Sharpe Ratio Comparison

The current IBMT Sharpe Ratio is 1.62, which is lower than the AUSM Sharpe Ratio of 3.96. The chart below compares the historical Sharpe Ratios of IBMT and AUSM, 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

IBMT vs. AUSM - Drawdown Comparison

The maximum IBMT drawdown since its inception was -3.18%, which is greater than AUSM's maximum drawdown of -0.42%. Use the drawdown chart below to compare losses from any high point for IBMT and AUSM.

Drawdown Indicators

	IBMT	AUSM	Difference
Max Drawdown Largest peak-to-trough decline	-3.18%	-0.42%	-2.76%
Max Drawdown (1Y) Largest decline over 1 year	-3.10%	-0.42%	-2.68%
Current Drawdown Current decline from peak	-0.58%	-0.00%	-0.58%
Average Drawdown Average peak-to-trough decline	-0.74%	-0.08%	-0.66%
Ulcer Index Depth and duration of drawdowns from previous peaks	1.08%	0.14%	+0.94%

Volatility

IBMT vs. AUSM - Volatility Comparison

iShares iBonds Dec 2031 Term Muni Bond ETF (IBMT) has a higher volatility of 1.36% compared to Allspring Ultra Short Municipal ETF (AUSM) at 0.13%. This indicates that IBMT's price experiences larger fluctuations and is considered to be riskier than AUSM based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	IBMT	AUSM	Difference
Volatility (1M) Calculated over the trailing 1-month period	1.36%	0.13%	+1.23%
Volatility (6M) Calculated over the trailing 6-month period	2.36%	0.45%	+1.91%
Volatility (1Y) Calculated over the trailing 1-year period	3.00%	0.73%	+2.27%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	3.88%	0.73%	+3.15%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	3.88%	0.73%	+3.15%

IBMT vs. AUSM - Expense Ratio Comparison

Both IBMT and AUSM have an expense ratio of 0.18%, making them cost-effective options compared to the broader market, where average expense ratios typically range from 0.3% to 0.9%.

Dividends

IBMT vs. AUSM - Dividend Comparison

IBMT's dividend yield for the trailing twelve months is around 3.44%, more than AUSM's 2.61% yield.

Position	TTM	2025
AUSM Allspring Ultra Short Municipal ETF	2.61%	1.26%
IBMT iShares iBonds Dec 2031 Term Muni Bond ETF	3.44%	2.98%

Frequently Asked Questions

Can I hold both IBMT and AUSM in my portfolio?

IBMT and AUSM have a correlation of 0.09, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, IBMT or AUSM?

IBMT has higher volatility (1.36%) compared to AUSM (0.13%). In terms of maximum drawdown, IBMT dropped -3.18% vs AUSM's -0.42%.

Which ETF is better, IBMT or AUSM?

On 1-year performance, IBMT leads with 4.84% vs 2.89% for AUSM. Both ETFs have the same 0.18% expense ratio. On volatility, AUSM has been the lower-risk option at 0.13%. The better choice depends on whether you care most about return, fees, risk, or income.

Which ETF has performed better, IBMT or AUSM?

Over the 1-year period, IBMT has performed better with a 4.84% return vs 2.89%. Past performance does not guarantee future results, so compare this with risk, fees, and fund exposure.

Which ETF is cheaper, IBMT or AUSM?

IBMT and AUSM have the same expense ratio: 0.18% per year.

Which ETF pays a higher dividend yield, IBMT or AUSM?

IBMT has the higher dividend yield at 3.44%, compared with 2.61% for AUSM.

What is the main difference between IBMT and AUSM?

They also come from different issuers: iShares and Allspring.

Which has better risk-adjusted returns?

AUSM currently has the higher Sharpe Ratio (3.96 vs 1.62), 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.