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GMOCvsMBBETF Comparison

ETF 1
GMOC

GMO Ultra-Short Income ETF

This fund is part of
US Aggregate Bonds
+0.03%
VS
ETF 2
MBB

iShares MBS ETF

This fund is part of
MBS & ABS
-0.04%

GMO Ultra-Short Income ETF (GMOC) belongs to the US Aggregate Bonds segment. iShares MBS ETF (MBB) is part of the MBS & ABS segment. GMOC's top 3 sector exposures are Sovereign, Industrials and Government Agencies. In contrast, MBB's top sector exposures are Industrials, Non-Corporate and Finance. GMOC is more expensive with a Total Expense Ratio (TER) of 0.2%, versus 0.04% for MBB. GMOC is up 3.26% year-to-date (YTD) with +$27M in YTD flows. MBB performs worse with -1.78% YTD performance, and -$1.79B in YTD flows. Run a side-by-side ETF comparison of GMOC and MBB 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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GMOC vs MBB performance and flow charts

Performance

-2.0-1.5-1.0-0.50.00.5%Sep 16Sep 23Sep 30Oct 7Oct 14

Cumulative Flows

-3 B-2 B-1 B0 BSep 16Sep 23Sep 30Oct 7Oct 14

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Historic performance and flows
Data as of 10/16/2026
1M3MYTD1Y3Y5Y
Perf.
GMOC
MBB
+0.40%-0.25%
+1.03%-2.30%
+3.26%-1.78%
n/a-1.43%
n/a+17.04%
n/a-0.38%
Flows
GMOC
MBB
+$2M-$3.31B
+$2M-$2.66B
+$27M-$1.79B
--$5.06B
-+$8.97B
-+$13.89B
Volatility and drawdown
3M1Y3Y5Y
Volatility
GMOC
MBB
+0.21%+5.70%
n/a+4.61%
n/a+5.73%
n/a+6.66%
Max drawdown
GMOC
MBB
-0.01%-4.27%
n/a-5.38%
n/a-5.38%
n/a-16.94%
Max drawdown duration
GMOC
MBB
4d52d
n/a229d
n/a229d
n/a1405d
Trading data

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GMOC
MBB
Last sale
10/16/2026 at 1:30 PM
$50.14
$90.52
Previous close
10/15/2026
$50.13
$90.59
Consolidated volume
10/15/2026
Average volume
30 days
Average discount or premium
30 days
Average Bid/Ask spread
30 days
Replication quality
Data as of September 30, 2026
1-year trailing difference

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GMOC
is actively managed and doesn’t replicate an index

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GMOC
MBB
Tracking error
Tracking difference
1 year cumulative return difference
Best
Worst
Daily return difference
Average
Worst
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Main metrics
Last update 10/16/2026 at 1:30 PM
Live
Closed
GMOC
MBB
Last price
$50.14
$90.52
1D performance
+0.02%
-0.08%
AuM$34.47 M$35.27 B
E/R0.2%0.04%
Characteristics
GMOC
MBB
Management strategyActivePassive
ProviderGMOiShares
Benchmark-Bloomberg U.S. MBS Index
N° of holdings191237
Asset class-Bonds
Trailing 12m distribution yield
Join
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Inception dateOctober 27, 2025March 13, 2007
ESGNoNo
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Exposure

Countries

GMOC
USA
27.87%
Other
72.13%
MBB
USA
28.44%
Other
71.56%

Sectors

GMOC
Sovereign
25.94%
Other
74.06%
MBB
Industrials
20.61%
Non-Corporate
7.6%
Other
71.79%
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Diversification

GMOC

Total weight of top 15 holdings out of 15

61.58%
MBB

Total weight of top 15 holdings out of 15

16.82%

Top 15 holdings

Data as of August 31, 2026
GMOC
US94949GAW15
7.64%
US48249VBE02
5.10%
US95023AAL44
4.95%
US69702EAJ47
4.65%
US87167NDL64
4.42%
US05684GAQ91
4.21%
USA, Notes 3.5% 31jan2028, USD (U-2028)
4.03%
USA, Notes 3.875% 31dec2027, USD (AH-2027)
4.01%
US39809TAW71
3.95%
USA, Notes 3.375% 30nov2027, USD (BL-2027)
3.46%
US92332NBC83
3.37%
US07132JBL70
3.19%
USA, Notes 3.5% 30sep2027, USD (BH-2027)
3.12%
USA, Notes 3.625% 31aug2027, USD (BG-2027)
2.86%
USA, Notes FRN 31jul2028, USD (BF-2028)
2.63%
MBB
BlackRock Cash Funds - Institutional
7.60%
US01F0526982
1.26%
US21H0526945
1.05%
FR SD8146, 2% 1may2051, USD (ABS)
0.98%
US01F0506927
0.87%
US21H0606978
0.63%
G2 MB0025, 5% 20nov2054, USD (ABS)
0.55%
US21H0506988
0.55%
G2 MA7648, 2% 20oct2051, USD (ABS)
0.51%
US36179WTX64
0.50%
FN MA4492, 2% 1dec2051, USD (ABS)
0.49%
US36179WJR07
0.48%
US21H0426955
0.48%
FR SD8140, 2% 1apr2051, USD (ABS)
0.47%
FN MA4465, 2% 1nov2051, USD (ABS)
0.42%
Frequently asked questions about GMOC and MBB

How have the GMOC and MBB ETFs performed in 2026?

As of October 16, 2026, GMOC is up 3.26% year-to-date (YTD), while MBB has lost -1.78%. That puts GMOC better performer ahead so far this year.

Which ETF is attracting more investor money: GMOC or MBB?

Year-to-date, the GMOC ETF saw +$27M in flows, compared to -$1.79B for MBB.

Which ETF is bigger: GMOC or MBB?

As of October 16, 2026, GMOC holds $34.47 M in assets under management (AUM), while MBB manages $35.27 B.

What sectors do the GMOC and MBB ETFs invest in?

GMOC leans toward sectors like Sovereign. Meanwhile, MBB focuses on Industrials and Non-Corporate.

What are the top holdings of the GMOC ETF and MBB ETF?

GMOC top holdings include US94949GAW15, US48249VBE02 and US95023AAL44. MBB holds in its top three: BlackRock Cash Funds - Institutional, US01F0526982 and US21H0526945.

Which ETF is more diversified: GMOC or MBB?

GMOC holds 57 securities with 61.58% of its assets in the top 15. MBB has 9405 securities and a top 15 weight of 16.82%.

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