iShares MBS ETF
$90.47−0.97 (−1.07%)
- Expense ratio
- 0.04%
- Fund size
- $39.0B
- 1Y return
- +0.5%
- Yield · Last 12 months
- 4.42%
- Holdings
- 11214
- Volume · 30D
- 2.3M sh
- NAV per share
- $91.61
- 52W range
The ETF.net MBB Grade
Score 69 of 100 sits in the A band. Bands: A ≥ 70, B ≥ 55, C ≥ 40, D ≥ 25, F < 25; the scale skips E.
Cost
What you pay to own it — the expense ratio plus trading frictions, ranked within its category.AScore 94Category rankMission
How faithfully it does the job it claims — tracking its mandate or index with minimal slippage.CScore 48Category rankRisk
How violently it can move — volatility, drawdown depth, and downside capture versus its category.DScore 29Category rankTradability
How cheaply and easily you can get in and out — liquidity, spread, and premium/discount stability.AScore 89Category rankHoldings
What it actually owns — the quality, breadth, and concentration of the underlying portfolio.BScore 69Category rankDurability
Whether it will still be here — the fund’s assets, age, flows, and issuer staying power.AScore 92Category rank
Our read on MBB
ALaunched in 2007, MBB is the plain-vanilla way to own U.S. agency mortgage bonds: one of the biggest and busiest funds in a small niche, tracking the Bloomberg U.S. MBS Index for four basis points.
The fund seeks to track an index composed of U.S. agency mortgage-backed securities.
Why people hold it
- Four basis points to rent the entire agency mortgage market, against a category median near 0.35%. In low-coupon bond land, that gap compounds quietly.
- Scale is the real feature: one of the largest and most actively traded funds in the mortgage-bond category, which generally shows up as tighter spreads.
- Pays monthly, and the mandate stays narrow: an index of U.S. agency mortgage-backed securities, nothing exotic bolted on.
- Among the stronger builds in a thin peer group of mortgage-bond ETFs, on the combination of cost, trading friction and issuer staying power.
Worth knowing
- This is one slice of the bond market. Agency mortgage paper only, with no Treasuries or corporates alongside it.
- Mortgage bonds cut both ways with rates: borrowers refinance when yields fall and sit tight when they rise, so the portfolio's duration shifts underneath you.
- On price it's a photo finish: SPMB tracks the same index at the same 0.04%, and VMBS runs a basis point cheaper.
MBB Holdings
- Bonds
- 11,214
- 12%
- BLACKROCK CASH CL INST SL AGENCY
Geography
- United States100.00%
MBB Performance
Shows how $10,000 changes over the selected period, with cash distributions reinvested at the closing price on each ex-dividend date.
MBB$10,046
Returns run to the Sep 22, 2026 close, with cash distributions reinvested. Each period starts on the same date that many months or years earlier. Periods over one year show the average yearly return.
| Period | MBB |
|---|---|
| Year to date | −1.2% |
| 1 month | −1.4% |
| 3 months | −1.9% |
| 1 year | +0.5% |
| 3 years | +4.7% |
| 5 years | −0.1% |
| 10 years | +1.0% |
Calendar-year total return with cash distributions hypothetically reinvested at the ex-dividend date’s closing price. The current year shows year to date.
| Year | Return bar | MBB |
|---|---|---|
| 2026 YTD | −1.2% | |
| 2025 | +8.4% | |
| 2024 | +1.3% | |
| 2023 | +5.0% | |
| 2022 | −11.7% | |
| 2021 | −1.6% | |
| 2020 | +4.1% |
MBB in the news
MBB Dividends
- 4.42%
- $4.04
- $0.34 per share
- Monthly
Distribution history
| Ex-date | Pay date | Amount per share |
|---|---|---|
| Sep 1, 2026 | Sep 4, 2026 | $0.34 |
| Aug 3, 2026 | Aug 6, 2026 | $0.34 |
| Jul 1, 2026 | Jul 7, 2026 | $0.34 |
| Jun 1, 2026 | Jun 4, 2026 | $0.33 |
| May 1, 2026 | May 6, 2026 | $0.33 |
| Apr 1, 2026 | Apr 7, 2026 | $0.33 |
| Mar 2, 2026 | Mar 5, 2026 | $0.33 |
| Feb 2, 2026 | Feb 5, 2026 | $0.33 |
| Dec 19, 2025 | Dec 24, 2025 | $0.33 |
| Dec 1, 2025 | Dec 4, 2025 | $0.35 |
| Nov 3, 2025 | Nov 6, 2025 | $0.34 |
| Oct 1, 2025 | Oct 6, 2025 | $0.34 |
MBB Risk
- 6.4%
How it’s calculated: standard deviation
The sample standard deviation of monthly total returns, multiplied by the square root of 12.
Uses up to 36 complete months, with at least 12 required. Total returns include reinvested distributions.
- 0.02
How it’s calculated: Sharpe ratio
Subtract each month’s Treasury-bill return from the fund’s monthly total return.
Divide the average of those excess returns by their sample standard deviation, then multiply by the square root of 12.
Uses up to 36 complete months, with at least 12 required. Each month uses the Treasury yield quoted at the end of the previous month.
- −17.0%
How it’s calculated: maximum drawdown
The largest percentage decline from an earlier peak, using total returns with reinvested distributions.
Uses up to five years through the last close, with at least 12 months required.
- 1.14
How it’s calculated: beta
The beta figure is supplied by FMP. The comparison index depends on the fund’s broad asset class.
MBB Cost
0.04%
MBB0.04%
- The middle half of Mortgage-Backed Securities funds
- Median 0.32%
2 of the 24 Mortgage-Backed Securities funds charge less.