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ETF · holdings as filed 2026-05-31

What's inside MBB?

iShares MBS ETF
Holdings
11,145
positions in the fund
Top 10
12%
of fund assets
Expense ratio
0.04%
net, per year
Fund size
$39B
total net assets

Top 20 holdings

RankLogoTicker / NameWeight
1
X
XTSLABLCKRCK CASH-TRSRY-SL AGNCY
6.46%
2
BOND
Freddie Mac mortgage pool#FR SD8146
1.00%
3
G
G2SF 5.5 6.11G2SF 5.5 6/11
0.90%
4
F
FNCL 5.5 6.11FNCL 5.5 6/11
0.79%
5
G
G2SF 5 6.11G2SF 5 6/11
0.64%
6
F
FNCL 5 6.11FNCL 5 6/11
0.61%
7
BOND
Ginnie Mae mortgage pool#G2 MB0025
0.52%
8
BOND
Ginnie Mae mortgage pool#G2 MA7648
0.52%
9
BOND
Ginnie Mae mortgage pool#G2 MA7766
0.51%
10
F
FN MA4492FN MA4492
0.50%
11
BOND
Freddie Mac mortgage pool#FR SD8140
0.48%
12
BOND
G2sf 6 6/11
0.44%
13
BOND
Ginnie Mae mortgage pool#G2 MA7472
0.43%
14
F
FN MA4465FN MA4465
0.42%
15
F
FN FS4654FN FS4654
0.42%
16
BOND
Ginnie Mae mortgage pool#G2 MA9171
0.39%
17
BOND
Ginnie Mae mortgage pool#G2 MA7935
0.35%
18
BOND
Ginnie Mae mortgage pool#G2 MA7367
0.34%
19
F
FNCL 6 6.11FNCL 6 6/11
0.32%
20
F
FN FS9130FN FS9130
0.31%
Sectors tap a row to see its top 10 holdings
Top holdings — Unclassified
Your 10 largest positions in this sector
1
G
G2SF 5.5 6.11G2SF 5.5 6/11
0.90%
2
F
FNCL 5.5 6.11FNCL 5.5 6/11
0.79%
3
G
G2SF 5 6.11G2SF 5 6/11
0.64%
4
F
FNCL 5 6.11FNCL 5 6/11
0.61%
5
F
FN MA4492FN MA4492
0.50%
6
F
FN MA4465FN MA4465
0.42%
7
F
FN FS4654FN FS4654
0.42%
8
F
FNCL 6 6.11FNCL 6 6/11
0.32%
9
F
FN FS9130FN FS9130
0.31%
10
F
FN CA9034FN CA9034
0.27%
Geography tap a row to see its top 10 holdings
Top holdings — United States
Your 10 largest positions in this country
1
X
XTSLABLCKRCK CASH-TRSRY-SL AGNCY
6.46%
2
BOND
Freddie Mac mortgage pool#FR SD8146
1.00%
3
G
G2SF 5.5 6.11G2SF 5.5 6/11
0.90%
4
F
FNCL 5.5 6.11FNCL 5.5 6/11
0.79%
5
G
G2SF 5 6.11G2SF 5 6/11
0.64%
6
F
FNCL 5 6.11FNCL 5 6/11
0.61%
7
BOND
Ginnie Mae mortgage pool#G2 MB0025
0.52%
8
BOND
Ginnie Mae mortgage pool#G2 MA7648
0.52%
9
BOND
Ginnie Mae mortgage pool#G2 MA7766
0.51%
10
F
FN MA4492FN MA4492
0.50%
Geography reflects each issuer's registered business address per SEC EDGAR filings where available, falling back to the exchange or listing where no SEC filing exists — not necessarily where a company's stock is primarily listed (e.g. TSMC is classified as Taiwan even though its ADR trades on the NYSE).
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Data source: official SEC Form N-PORT filings (as of 2026-05-31); expense ratio from SEC prospectus (risk/return) filings. Fund holdings are disclosed quarterly and may reflect a 60-day reporting delay.
Informational and educational only — not investment advice.