MBB · iShares MBS ETF
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MBB tracks an index of mortgage-backed securities and returned −0.8% over the past year.
MBB returned −0.8% over the year to Oct 28, 2026, charges 0.04% a year and holds $35.5bn in net assets on Oct 28, 2026.
Promise check: DeliveredOver the year to Oct 28, 2026, MBB returned −0.8% against −1.1% for SPMB, which tracks the same Bloomberg U.S. MBS Index. Fees aside, MBB finished 0.30 points ahead of SPMB.
MBB risk and return scorecard
vs SPMB · Feb 2009 to Oct 2026 · 924 weekly returns · dividend-adjusted
Computed by ETFIQ from Tiingo daily prices and ETFIQ's distribution records; risk-free rate: U.S. Treasury, Daily Treasury Bill Rates, 13-week coupon equivalent Method · Data
Money in and out
Net fund flows · Oct 23, 2026What you earned
What does it hold, and how long?
Holdings filed for Aug 31, 2026 (N-PORT)More on MBB
Every number below is on this page. Open what you need.Price and total return, 1 year
$91.41−0.2%1 day, priceClose, Oct 28, 2026
Total return adds every distribution, reinvested. Computed by ETFIQ from Tiingo daily prices.
Source: Tiingo end-of-day prices. Data as of Oct 28, 2026. Updated every trading night. Report a data error
| Window | Total return | Benchmark (SPMB) | Gap to SPMB |
|---|---|---|---|
| 1M Sep 28 – Oct 28, 2026 | +2.4% | +2.1% | +0.3 pts |
| 3M Jul 29 – Oct 28, 2026 | −0.8% | −1.1% | +0.3 pts |
| 6M Apr 29 – Oct 28, 2026 | −1.2% | −1.4% | +0.2 pts |
| YTD Dec 31, 2025 – Oct 28, 2026 | −0.8% | −1.0% | +0.2 pts |
| 1Y Oct 28, 2025 – Oct 28, 2026 | −0.8% | −1.1% | +0.3 pts |
| 3Y Oct 27, 2023 – Oct 28, 2026 | +19.2% | +18.8% | +0.4 pts |
| 5Y Oct 29, 2021 – Oct 28, 2026 | +0.6% | +0.4% | +0.2 pts |
| 10Y Oct 28, 2016 – Oct 28, 2026 | +11.4% | +10.5% | +0.9 pts |
| Since launch Mar 16, 2007 – Oct 28, 2026 | +63.8% | not available | not available |
| Since launch, annualised Mar 16, 2007 – Oct 28, 2026 | +2.5% | – | – |
Total returns, distributions reinvested.
Source: Tiingo end-of-day prices, with distributions reinvested.
How far can rates rise in a year before the year's income is gone?
That is the share of the 20 government bond ETFs with an intermediate duration sitting at or below MBB.
One year's income against today's duration; it ignores credit risk, and both numbers move. Where the fund sits in this set, not a rating. Do not average it with another category's score.
How far rates could rise before a year's income is gone, ranked against 20 government bond ETFs with an intermediate duration. 100 is best. How it is computed
MBB paid 4.46% of its NAV in income over the year to Oct 28, 2026, with a duration of 5.65 years: rates could rise 0.79 percentage points in a year before that income was gone.
Money in and out
Daily data · as of Oct 23, 2026MBB: in the year to Oct 23, 2026, net $4.8bn went out; in the month to Oct 23, 2026, $1.9bn went out.
Oct 21, 2026 to Oct 23, 2026
Sep 28, 2026 to Oct 23, 2026
Jul 28, 2026 to Oct 23, 2026
Jan 2, 2026 to Oct 23, 2026
Oct 28, 2025 to Oct 23, 2026
SEC filings, then daily counts
MBB, net flow each trading day over the 63 sessions from Jul 28, 2026 to Oct 23, 2026: money came in on 2 days and went out on 8 days.
Money in on 2 of the 63 trading days, out on 8.
MBB, net flow each trading day over the 249 sessions from Oct 28, 2025 to Oct 23, 2026: money came in on 6 days and went out on 34 days.
Money in on 6 of the 249 trading days, out on 34.
MBB, net flow each trading day over the 400 sessions from Mar 24, 2025 to Oct 23, 2026: money came in on 18 days and went out on 41 days.
Money in on 18 of the 400 trading days, out on 41.
MBB is one of 2 US-listed ETFs tracking the Bloomberg U.S. MBS. The money in and out of all 2, side by side.
Computed by ETFIQ from iShares’s daily data: each day’s change in shares outstanding times the previous day’s net asset value.
How this is computed
Percentages are of net assets at the start of each window. Numbers are net: money in less money out. Checked against the filing: The month’s daily sum and the filing’s B.6 number agree within rounding or, where the filing’s is larger, within rounding plus the fund’s creation and redemption fees. The full rule is in the fund’s flows file. Every day and month ETFIQ holds for MBB, back to Sep 2019, is in its flows file. Flows across every fund · How these flows are computed · Compare MBB with other funds in the flows tool
Every trading day, last 3 months63 days
Most recent first.
Week by week, last year52 weeks
Net flow into MBB each week, Oct 28, 2025 to Oct 23, 2026, most recent first, each week named by its last trading day with data. Computed by ETFIQ.
Month by month, money in and money outNov 2023 to Oct 2026
MBB, money in and money out each month from Nov 2023 to Sep 2026: two bars a month, money in above the line and money out below. Bars for Nov 2023 to May 2026 are from MBB’s SEC filings (N-PORT item B.6), and for Jun 2026 to Sep 2026 ETFIQ’s sums of its days. Oct 2026 is still in progress, so it is in the list and not drawn. Of the 36 months listed, money came in on net in 24 and went out in 10.
Bars for Nov 2023 to May 2026 are from MBB’s SEC filings (N-PORT item B.6), and for Jun 2026 to Sep 2026 ETFIQ’s sums of its days. Of the 36 months listed, money came in on net in 24 and went out in 10.
Most recent first.
How this is computed
N-PORT months: money in is sales plus reinvestments; money out is redemptions. Months summed from daily data: money in adds the days money came in; money out adds the days it went out.
N-PORT months are the filed sales plus reinvestments less redemptions. Later months add up the daily data; the Source column names any missing day.
Source: ETFIQ, from the fund’s daily share counts and net asset values, and its SEC N-PORT filings. Data as of Oct 23, 2026.
MBB key stats
Trading
as of Oct 28, 2026
Trades like a giant: trades at a typical spread of 0.01%.
Also against IWB, TLT, BSV, IEF, VNQ, VGSH, MGK, EEM, RDVY, EWY, IGSB, IGIB, SPHQ, SCHP, TIP, IWO, NOBL, IBB, XBI, BOND, CGBL, JNK, MAGS, HGER, XRT, AGG, VMBS, SPMB, JMTG, JMBS, SMBS, FSEC, PMBS, IVV, SPY, VTI, QQQ, VUG, VEA, IEFA, SPYM, VTV, VXUS, IEMG, GLD, VWO, XLK, IWF, IJH, SCHD, VIG, IJR, VO, RSP, ITOT, IWD, BNDX, VT, VYM, VB, IWM, SCHF, VEU, SCHG, IAU, SPYG, XLF, IUSB, VTEB, BIL, QUAL, VONG, XLV, DIA, XLE, DGRO, SCHB, VCSH, GOVT, DYNF, VGIT, CGDV, VBR, IDEV, ACWI, JAAA, AVUV, XLI, GLDM, LQD, VXF, VGK, VOOG, FNDX, SHY, AVEM, EMXC, SLV, USHY, MDY, CGGR, IYW, USMV, XLU, EWJ, DVY, VBK, VOE, AVLV, XLY, SPMO, FTEC, XLC, SDY, SHV, VYMI, VTIP, DFUS, AVDV, PULS, COWZ, VHT, MTUM, ACWX, HYG, USFR, IEI, BINC, VTWO, MINT, HDV, AVUS, XLP, BOXX, PVAL, EMB, VBIL, EWT, XLG, PFF, SPSB, SCHH, IGM, ONEQ, VDE, VGLT, EWZ, FDVV, VUSB, VLUE, EZU, VPL, URTH, XLB, XLRE, PDBC, VPU, IJS, FBCG, SPYD, VCLT, IJT, VDC, VOX, INDA, XOP, GRNY, KRE, AOR, IYR, HYMB, FXI, SIVR, EDV, GARP, ILF, SPHD, USO, IYE, BITO, XHB, IWC, DGRW, MOAT, FENI, XOVR, FLKR, BWET.
About MBB
12 seats on MBB, as of Oct 28, 2026: 1 Supports, 2 Mixed, 2 Challenges, 4 Not enough data, 3 Does not apply.
Questions people ask about MBB
- How has MBB performed?
- Over the year to Oct 28, 2026, MBB returned −0.8% with distributions reinvested, against −1.1% for its benchmark, the Bloomberg U.S. MBS Index. Over three years the number is +19.2%.
- What does MBB cost?
- The prospectus expense ratio is 0.04% a year.
- How far is MBB below its high?
- 2.9% below its high of Feb 27, 2026, measured on the reinvested series to Oct 28, 2026.
Links are sources, not endorsements.
Cite this pageCitation, APA and Markdown
ETFIQ, MBB, bond fund, data as of Oct 28, 2026. https://etfiq.com/funds/mbb
ETFIQ. (Oct 28, 2026). MBB, bond fund. Retrieved from https://etfiq.com/funds/mbb
[MBB, bond fund (ETFIQ, Oct 28, 2026)](https://etfiq.com/funds/mbb)
Free to use with attribution for data ETFIQ computes; issuer data stays under its owner's terms. The underlying files are at Open data.
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<figure style="margin:0;max-width:640px">
<a href="https://etfiq.com/funds/mbb"><img src="https://etfiq.com/assistant/api/embed/core/mbb.svg" alt="MBB: MBB over 1 year: total return −0.8%, its benchmark Bloomberg U.S. MBS Index through SPMB −1.1%, +0.3 pts. Data to Oct 28, 2026." width="640" style="max-width:100%;height:auto"></a>
<figcaption style="font:13px/1.5 sans-serif">MBB: MBB over 1 year: total return −0.8%, its benchmark Bloomberg U.S. MBS Index through SPMB −1.1%, +0.3 pts. Data to Oct 28, 2026. Data: <a href="https://etfiq.com/funds/mbb">ETFIQ</a></figcaption>
</figure>The day's ETF flows, a comparison and one number. Every trading morning. About the Daily
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