MBB
iShares MBS ETF
iShares MBS ETF is an exchange-traded fund incorporated in the USA. The ETF 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.
Mortgage
FIXED INCOME
Passive
MANAGEMENT STYLE
$ 41.5 B
ASSETS UNDER MGMT
4 bp
EXPENSES
Fund Basics
| Inception date | Mar 13, 2007 |
| Regulation | Open-End Investment Company |
| Fund Website | link... |
| Distributions | Monthly |
| Currency | USD |
| Holdings Transparency | Full |
| Derivatives-based | No |
| Options available | Yes |
| Currency hedged | No |
| Fund of funds | No |
Top 10 Holdings
| BLACKROCK CASH CL INST SL AGENCY | 3.5 % |
| FHLMC 30YR UMBS SUPER - 2.0 2051-05-01 | 0.9 % |
| GNMA2 30YR - 2.0 2051-10-20 | 0.6 % |
| GNMA2 30YR - 2.0 2051-12-20 | 0.6 % |
| FHLMC 30YR UMBS SUPER - 2.0 2051-04-01 | 0.6 % |
| GNMA2 30YR - 2.5 2051-07-20 | 0.5 % |
| FNMA 30YR UMBS - 2.0 2051-11-01 | 0.5 % |
| FNMA 30YR UMBS SUPER - 2.0 2051-07-01 | 0.5 % |
| GNMA2 30YR - 6.5 2054-07-20 | 0.4 % |
| GNMA2 30YR - 5.0 2054-11-20 | 0.4 % |
Constituent Breakdown
| No. of constituents | 1,032 |
| No. of distinct issuers | 393 |
| Coverage | 91% |
| Fixed/floating rate | 100% / 0% |
| Investment grade | 100% |
| Inflation protected | 0% |
| Non-standard maturity (callable, etc.) | 100% |
Issuer Type Breakdown
Top Issuers
| FANNIE MAE | 40.9 % |
| FREDDIE MAC | 26.5 % |
| GINNIE MAE | 23.6 % |
Historical Performance
Standardized Performance (as of 02/28/2026)
| YTD | 1 YR | 2 YR | 3 YR | 5 YR | 10 YR | 20 YR | Incep. | |
|---|---|---|---|---|---|---|---|---|
| Price Returns | 1.8% | 3.0% | 2.7% | 1.4% | -2.4% | -1.2% | -- | -0.2% |
| Dividend Yield | 0.4% | 4.5% | 4.3% | 4.0% | 3.0% | 2.7% | -- | 3.0% |
| Total Returns | 2.1% | 7.5% | 7.0% | 5.4% | 0.6% | 1.5% | -- | 2.8% | Ann. Volatility | 3.3% | 4.8% | 5.4% | 6.6% | 6.7% | 5.2% | -- | 4.6% |
Market Correlations
| versus... | Beta | R-squared |
| S&P 500 | 0.01 | 0% |
| MSCI EAFE | 0.05 | 3% |
| MSCI Emg Mkts | 0.01 | 0% |
Liquidity Measures
| Avg. volume (000) | 3,121 |
| ADV traded (mns) | $296 |
| Turnover | 0.7% |
| Avg. Bid/Ask (% of price) | 0.01% |
Technical Indicators
| 30d moving avg. (EMA) | $95.08 |
| Relative strength (RSI) | 43 |
| MACD/Signal | -0.36/-0.22 |
| Bollinger Bands (Upper/Lower) | $96.41/$93.83 |
| Short interest (% of AUM) | 0.8% |
Distributions
Assets Under Management (mns)
Money Flows (mns)
Short Interest (as % of shares outstanding)
Long Money Flows (mns)
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Credit Quality
Duration
Macaulay Duration
Modified Duration
SHORT
MED.
LONG TERM
8.8 yrs
Modified Duration
◁ INSENSITIVE
EXTREMELY SENSITIVE ▷
8.8%
ⓘ Our analysis shows this fund is likely to be moderately sensitive to changes in interest rates
Interest Rate Sensitivity Analysis
| Change in YTM |
New YTM |
Est. Price Change |
New Price |
|---|---|---|---|
| +300 bp | --% | --% | $-- |
| +200 bp | --% | --% | $-- |
| +150 bp | --% | --% | $-- |
| +100 bp | --% | --% | $-- |
| +75 bp | --% | --% | $-- |
| +50 bp | --% | --% | $-- |
| +25 bp | --% | --% | $-- |
| 0 bp | --% | --% | $-- |
| -25 bp | --% | --% | $-- |
| -50 bp | --% | --% | $-- |
| -75 bp | --% | --% | $-- |
| -100 bp | --% | --% | $-- |
| -150 bp | --% | --% | $-- |
| -200 bp | --% | --% | $-- |
| - 300bp | --% | --% | $-- |
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Yields
Disposition of YTM
Distribution Yield (Trailing 12 Months)
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ETF Research Center Fund Rating
The ALTAR Score™ is our measure of an ETF's overall investment merit. For fixed income funds, the Score is an estimate of risk-adjusted yield to maturity (calculation shown below). In effecient markets, the plot of ALTAR Scores™ vs. Duration should resemble the familiar yield curve. Funds that sit above the curve may offer better risk-adjusted returns than those that sit below the curve.
ALTAR Score™
MBB
4.9%
Cat. Avg
4.6%
Fund Category: Mortgage
| Adj. Yield to Maturity | -- bp |
| Less: Annual "default factor" | -- bp |
| Less: Expenses | 4 bp |
| Equals: ALTAR Score™ | 4.9% |
ALTAR Score™ vs. Duration (Mortgage Bond ETFs)