MBB vs SMBS
iShares MBS ETF against Schwab Mortgage-Backed Securities ETF: cost, size, returns, what they hold and how much of it is the same.
Overlap by weight
18%
1035 shared positions
Fee gap
1 bp
SMBS is cheaper
1-year return gap
0.5 pts
MBB is ahead
Larger fund
MBB
$35.2B
Side by side
| MBB | SMBS | |
|---|---|---|
| Fund | iShares MBS ETF | Schwab Mortgage-Backed Securities ETF |
| Issuer | iShares | Schwab |
| Category | Mortgage & Securitized | Mortgage & Securitized |
| Expense ratio | 0.04% | 0.03% |
| Assets | $35.2B | $6.4B |
| Average daily dollar volume | $676M | $42M |
| Listed | Mar 13, 2007 | Nov 18, 2024 |
| FrenzyCap score | 98 | 94 |
| 1-month return | −1.2% | −1.0% |
| 3-month return | −2.9% | −3.0% |
| Year to date | −5.0% | −5.3% |
| 1-year return | −5.6% | −6.1% |
| 30-day volatility | 6.7% | 6.8% |
| Worst drawdown, 1 year | −8.1% | −8.4% |
| Trailing 12-month yield | 4.50% | 5.38% |
| Holdings | 10,818 | 4,197 |
| Top 10 weight | 6.0% | 2.9% |
| Look-through P/E | — | — |
| Holdings vs fair value | — | — |
| Holdings above 200-day average | — | — |
| Net flow, latest 3 reported months | −$179M thru May 2026 | +$310M thru May 2026 |
| 30-day implied volatility | 8.3% | — |
| Holdings as of | as of Oct 19, 2026issuer data | as of May 31, 2026SEC filing |
Returns are price returns and exclude distributions. Flows are each fund's own latest reported months and may not cover the same period.
Largest shared holdings
32% of MBB · 33% of SMBS| Holding | MBB | SMBS |
|---|---|---|
| GNMA2 30YR, due Nov 20, 2054 | 0.59% | 0.47% |
| FHLMC 30YR UMBS, due Apr 1, 2056 | 0.25% | 0.25% |
| GNMA2 30YR, due Dec 20, 2054 | 0.25% | 0.19% |
| GNMA2 30YR, due Feb 20, 2051 | 0.16% | 0.18% |
| FNMA 30YR UMBS, due Jul 1, 2051 | 0.15% | 0.16% |
| GNMA2 30YR, due Sep 20, 2055 | 0.40% | 0.15% |
| GNMA2 30YR, due Nov 20, 2054 | 0.15% | 0.16% |
| GNMA2 30YR, due Jul 20, 2051 | 0.52% | 0.15% |
| FHLMC 30YR UMBS SUPER, due Dec 1, 2051 | 0.24% | 0.14% |
| GNMA2 30YR, due Dec 20, 2051 | 0.28% | 0.14% |
| GNMA2 30YR, due Jan 20, 2056 | 0.14% | 0.24% |
| GNMA2 30YR, due Dec 20, 2050 | 0.28% | 0.14% |
| FNMA 30YR UMBS, due Oct 1, 2051 | 0.32% | 0.13% |
| FHLMC 30YR UMBS SUPER, due May 1, 2051 | 1.05% | 0.13% |
| GNMA2 30YR, due Oct 20, 2054 | 0.17% | 0.13% |
| GNMA2 30YR, due Jan 20, 2056 | 0.13% | 0.14% |
| GNMA2 30YR, due Apr 20, 2052 | 0.23% | 0.13% |
| GNMA2 30YR, due Oct 20, 2054 | 0.13% | 0.12% |
| GNMA II 30YR, due Jul 20, 2053 | 0.16% | 0.12% |
| GNMA2 30YR, due Sep 20, 2051 | 0.22% | 0.12% |
| FNMA 30YR UMBS, due May 1, 2051 | 0.12% | 0.28% |
| GNMA2 30YR, due Aug 20, 2051 | 0.16% | 0.12% |
| GNMA2 30YR, due Sep 20, 2052 | 0.12% | 0.19% |
| FHLMC 30YR UMBS SUPER, due Oct 1, 2054 | 0.12% | 0.35% |
| GNMA2 30YR, due Oct 20, 2052 | 0.12% | 0.13% |
Sector mix of the stock holdings
No sector breakdown: these funds hold few classified stocks.
More: full overlap table · MBB holdings · SMBS holdings
Fund data comes from each fund's SEC filings and issuer disclosures and is shown with the date it is as of. SEC portfolio and flow filings become public about 60 days after the period they cover. Nothing here is investment advice; see Terms.