ETF Trace

Fund report

US-listed · United States

MBB

seeks to track the investment results of an index composed of investment-grade, mortgage-backed pass-through securities issued and/or guaranteed by U.S. government agencies.
iShares MBS ETF
US4642885887 · IRUK · BlackRock (iShares)

10,858 holdings as of 2026-10-12 · top 10 = 10.7% · TER 0.04%

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Concentration
Well diversifiedtop 10 = 10.7%
diversifiedconcentrated
GROWTH · PRICE DEVELOPMENTrebased to 0%
Holdings
10,858
as of 2026-10-12
Top 10
10.7%
TER
0.04%
cheaper than 94% of peers
Net assets
US$35.6B
reported in USD
Largest
4.7%
P / E
–
Sections
Holdings as of 2026-10-12.
01Overview
the fund's regulatory facts
Fund currency
USD
Domicile
United States
First listed
2007-02-28
Volatility 1Y
5.2%
Tracked index
Bloomberg U.S. MBS Index
How it tracks
Index, sampling
02Performance
market price return · as of 2026-10-28
1M
+2.0%
3M
-2.0%
6M
-3.4%
YTD
-4.0%
1Y
-5.0%
Trackingfund minus Bloomberg U.S. MBS Index · annualised
1Y return gap
-0.03 pp/yr
3Y return gap
-0.03 pp/yr
5Y return gap
-0.04 pp/yr
3Y tracking error
0.17%

A positive return gap means the fund finished ahead of the index over that window. The 3Y tracking error shows how variable that monthly gap was; lower means steadier tracking. MethodologyReturn gap and tracking errorReturn gap is the fund's return minus its index over the same months, converted to a yearly rate. Tracking error is the annualised standard deviation of those monthly fund-minus-index returns. Both lines come from the manager's own chart, in the same currency and the exact index variant the fund tracks. We use month-end values so different intraday valuation times are not mistaken for tracking error.. Not investment advice.

03Holdings
50 largest · as of 2026-10-12
#CompanyIdentifierWeight
1BlackRock Funds III: BlackRock Cash Funds: Institutional; SL Agency Shares USBISXX
4.9
2Freddie Mac USFRSD8146
1.1
3GNMA2 30YR TBA(REG C) USG230J
0.7
4Fannie Mae or Freddie Mac 5.5 11/15/2032 USFNCL
0.6
5Government National Mortgage Association USUS3618N5A332
0.6
6TBA GNMA2 30YR 5.5% OCT 26 USG2SF
0.6
7Government National Mortgage Association USUS36179WP937
0.6
8Government National Mortgage Association USUS36179WTX64
0.5
9Fannie Mae USUS31418D7E66
0.5
10Government National Mortgage Association USG2
0.5
11Freddie Mac USFRSD8140
0.5
12Fannie Mae USFNMA4465
0.5
13GNMA II POOL MB1070 USUS3618N6FL65
0.5
14Government National Mortgage Association USG2MA9171
0.4
15Ginnie Mae II Pool USUS3618N5VR78
0.4
16Government National Mortgage Association USUS36179WFG87
0.4
17FNMA TBA 5.0% NOV 30YR USFNCL
0.4
18Fannie Mae USUS3140XREC56
0.3
19Fannie Mae USUS31418DXK35
0.3
20Government National Mortgage Association USG2MA7826
0.3
21GNMA II POOL MB1142 USUS3618N6HU47
0.3
22Fannie Mae USFNMA4437
0.3
23Government National Mortgage Association USG2MA7534
0.3
24Fannie Mae USFNMA4305
0.3
25FNMA 30YR UMBS USUS3140Y9XH27
0.3
26Government National Mortgage Association USUS36179VZQ66
0.3
27Fannie Mae USUS3140QHBC84
0.3
28Government National Mortgage Association USG2MA7767
0.3
29GNMA2 30YR USUS3618N6P684
0.3
30FNMA TBA 6.0% NOV 30YR USFNCL
0.3
31UMBS 30YR 2.0 MBS-TBA 11/26 USUM30
0.3
32Fannie Mae or Freddie Mac 4 11/15/2034 USUM15
0.3
33Government National Mortgage Association USUS36179Y2N36
0.3
34Government National Mortgage Association USUS3618N5C569
0.3
35Freddie Mac 5 04/01/2056 USUS3142J6DQ38
0.3
36Freddie Mac USUS3132DWG982
0.3
37Freddie Mac USUS3132DWCT80
0.3
38FREDDIE MAC POOL FR 05/53 FIXED 4 USFR
0.2
39FNMA 30YR UMBS USUS3140Y9W837
0.2
40Fannie Mae Pool USFN
0.2
41Government National Mortgage Association USG2MA7987
0.2
42Government National Mortgage Association USG2MA7589
0.2
43Freddie Mac USUS3132DWJF14
0.2
44Fannie Mae USUS3140XHHS99
0.2
45Freddie Mac USUS3133KLYA96
0.2
46Government National Mortgage A 4.5 10/15/2033 USG2SF
0.2
47Fannie Mae USUS3140QVG328
0.2
48GNMA II TBA 5.0% OCT 30YR JMBO USG2SF
0.2
49Freddie Mac 5 05/01/2056 USFRRQ0118
0.2
50GNMA II TBA 5.0% NOV 30YR JMBO USG230J
0.2
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04Exposure
Bonds 94.8%Cash 4.7%
By country
USUnited States98.8%
CurrencyUSD 98.8%
05Similar funds
funds with comparable exposure
AGG
the US aggregate index (AGG)
1,098 shared companies
18.6%compare →

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