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SPMBvsAMUNETF Comparison

ETF 1

SPMB

State Street State Street SPDR Portfolio Mortgage Backed Bond ETF

This fund is part of

MBS & ABS

-0.1%

Full SPMB fund page

VS

ETF 2

AMUN

abrdn Ultra Short Municipal Income Active ETF

This fund is part of

Municipal Bonds

-0.06%

Full AMUN fund page

State Street State Street SPDR Portfolio Mortgage Backed Bond ETF (SPMB) belongs to the MBS & ABS segment. abrdn Ultra Short Municipal Income Active ETF (AMUN) is part of the Municipal Bonds segment. SPMB's top 3 sector exposures are Industrials, Finance and Government Agencies. In contrast, AMUN's top sector exposures are Municipal and Non-Corporate. SPMB is less expensive with a Total Expense Ratio (TER) of 0.04%, versus 0.74% for AMUN. SPMB is down -1.53% year-to-date (YTD) with +$655M in YTD flows. AMUN performs better with 1.88% YTD performance, and +$25M in YTD flows. Run a side-by-side ETF comparison of SPMB and AMUN below, and assess how they stack up in performance, liquidity, risk, exposure, holdings, and more, helping you select the best ETF for your investments.

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SPMB vs AMUN performance and flow charts

Performance

Cumulative Flows

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Daily, global ETF data for advanced analysis or integration into apps (API), from our partner Trackinsight.

Data Services

Historic performance and flows

Data as of 09/16/2026

		1M	3M	YTD	1Y	3Y	5Y
Perf.	SPMB AMUN	-1.66%+0.09%	-2.70%+0.54%	-1.53%+1.88%	-0.61%n/a	+13.34%n/a	-0.88%n/a
Flows	SPMB AMUN	+$53M+$651K	+$231M+$1M	+$655M+$25M	+$936M-	+$2.58B-	+$3.74B-

Volatility and drawdown

		3M	1Y	3Y	5Y
Volatility	SPMB AMUN	+4.80%+0.36%	+4.25%n/a	+5.94%n/a	+6.72%n/a
Max drawdown	SPMB AMUN	-3.00%-0.08%	-3.61%n/a	-5.40%n/a	-17.24%n/a
Max drawdown duration	SPMB AMUN	79d8d	199dn/a	318dn/a	1486dn/a

Trading data

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	SPMB	AMUN
Last sale 9/17/2026 at 1:30 PM	$21.66	$26.05
Previous close 09/16/2026	$21.52	$26.04
Consolidated volume 09/16/2026
Average volume 30 days
Average discount or premium 30 days
Average Bid/Ask spread 30 days

Replication quality

Data as of August 31, 2026

1-year trailing difference

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AMUN

is actively managed and doesn’t replicate an index

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	SPMB	AMUN
Tracking error
Tracking difference
1 year cumulative return difference
Best
Worst
Daily return difference
Average
Worst

Main metrics

Last update 9/17/2026 at 1:30 PM

Live

Closed

	SPMB	AMUN
Last price	$21.66	$26.05
1D performance	+0.65%	+0.04%
AuM	$7.01 B	$55.04 M
E/R	0.04%	0.74%

Characteristics

	SPMB	AMUN
Management strategy	Passive	Active
Provider	State Street Investment Management	abrdn
Benchmark	Bloomberg U.S. MBS Index	-
N° of holdings	554	17
Asset class	Bonds	-
Trailing 12m distribution yield	Join	Join
Inception date	January 15, 2009	October 17, 2025
ESG	No	No

More SPMB data on Trackinsight

More AMUN data on Trackinsight

Exposure

Countries

SPMB

USA

32.64%

Other

67.36%

AMUN

USA

33.29%

Other

66.71%

Sectors

SPMB

Industrials

32.31%

Other

67.69%

AMUN

Municipal

33.11%

Other

66.89%

Diversification

SPMB

Total weight of top 15 holdings out of 15

9.28%

AMUN

Total weight of top 15 holdings out of 15

53.8%

Top 15 holdings

Data as of July 31, 2026

SPMB

US3142J6C840

1.16%

US01F0526800

0.86%

FN MA4547, 2% 1feb2052, USD (ABS)

0.78%

US3142J6BK85

0.76%

US01F0506844

0.70%

FR SD8212, 2.5% 1may2052, USD (ABS)

0.60%

US3132DWMY65

0.55%

G2 MB0424, 5.5% 20jun2055, USD (ABS)

0.54%

FN MA4701, 4.5% 1aug2052, USD (ABS)

0.51%

US01F0606834

0.50%

US21H0506806

0.49%

FN FA0608, 5.5% 1feb2055, USD (ABS)

0.49%

FN MA4465, 2% 1nov2051, USD (ABS)

0.47%

FN FS2040, 2% 1feb2052, USD (ABS)

0.44%

US3132DWKV45

0.43%

AMUN

Massachusetts Port Authority, 5% 1jul2043, USD (2016-B)

4.70%

Tennessee Energy Acquisition Corp., 5.625% 1sep2026, USD

4.14%

US46640KYU23

4.13%

US546598AA16

3.95%

US230589AB90

3.81%

Chandler Industrial Development Authority, 5% 1sep2052, USD (2022-2)

3.79%

Newark, 4.25% 5may2027, USD (2026)

3.77%

US478232SD45

3.77%

US88035TZV50

3.76%

US34074EAF60

3.76%

US7386297S79

3.75%

Mississippi Business Finance Corp., FRN 1nov2032, USD (2007A)

3.08%

US414008CX87

2.77%

PEFA Inc., 5% 1sep2049, USD (2019)

2.35%

US06964KAB26

2.26%

Frequently asked questions about SPMB and AMUN

How have the SPMB and AMUN ETFs performed in 2026?

As of September 16, 2026, SPMB is down -1.53% year-to-date (YTD), while AMUN has returned 1.88%. That puts AMUN better performer ahead so far this year.

Which ETF is attracting more investor money: SPMB or AMUN?

Year-to-date, the SPMB ETF saw +$655M in flows, compared to +$25M for AMUN.

Which ETF is bigger: SPMB or AMUN?

As of September 16, 2026, SPMB holds $7.01 B in assets under management (AUM), while AMUN manages $55.04 M.

What sectors do the SPMB and AMUN ETFs invest in?

SPMB leans toward sectors like Industrials. Meanwhile, AMUN focuses on Municipal.

What are the top holdings of the SPMB ETF and AMUN ETF?

SPMB top holdings include US3142J6C840, US01F0526800 and FN MA4547, 2% 1feb2052, USD (ABS). AMUN holds in its top three: Massachusetts Port Authority, 5% 1jul2043, USD (2016-B), Tennessee Energy Acquisition Corp., 5.625% 1sep2026, USD and US46640KYU23.

SPMBvsAMUNETF Comparison

State Street State Street SPDR Portfolio Mortgage Backed Bond ETF

abrdn Ultra Short Municipal Income Active ETF

SPMB vs AMUN performance and flow charts

Performance

Cumulative Flows

Get all the metrics on this page, and more, through a reliable ETF data feed

Countries

Sectors

Diversification

Top 15 holdings

How have the SPMB and AMUN ETFs performed in 2026?

As of September 16, 2026, SPMB is down -1.53% year-to-date (YTD), while AMUN has returned 1.88%. That puts AMUN better performer ahead so far this year.

Which ETF is attracting more investor money: SPMB or AMUN?

Year-to-date, the SPMB ETF saw +$655M in flows, compared to +$25M for AMUN.

Which ETF is bigger: SPMB or AMUN?

As of September 16, 2026, SPMB holds $7.01 B in assets under management (AUM), while AMUN manages $55.04 M.

What sectors do the SPMB and AMUN ETFs invest in?

SPMB leans toward sectors like Industrials. Meanwhile, AMUN focuses on Municipal.

What are the top holdings of the SPMB ETF and AMUN ETF?

SPMB top holdings include US3142J6C840, US01F0526800 and FN MA4547, 2% 1feb2052, USD (ABS). AMUN holds in its top three: Massachusetts Port Authority, 5% 1jul2043, USD (2016-B), Tennessee Energy Acquisition Corp., 5.625% 1sep2026, USD and US46640KYU23.

Which ETF is more diversified: SPMB or AMUN?

SPMB holds 2713 securities with 9.28% of its assets in the top 15. AMUN has 63 securities and a top 15 weight of 53.8%.

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