MBB vs SPMB
iShares MBS ETF against State Street SPDR Portfolio Mortgage Backed Bond ETF: cost, size, returns, what they hold and how much of it is the same.
Overlap by weight
18%
817 shared positions
Fee gap
0 bp
same fee
1-year return gap
0.1 pts
SPMB is ahead
Larger fund
MBB
$35.2B
Side by side
| MBB | SPMB | |
|---|---|---|
| Fund | iShares MBS ETF | State Street SPDR Portfolio Mortgage Backed Bond ETF |
| Issuer | iShares | State Street SPDR |
| Category | Mortgage & Securitized | Mortgage & Securitized |
| Expense ratio | 0.04% | 0.04% |
| Assets | $35.2B | $6.8B |
| Average daily dollar volume | $676M | $50M |
| Listed | Mar 13, 2007 | Jan 15, 2009 |
| FrenzyCap score | 98 | 95 |
| 1-month return | −1.2% | −1.3% |
| 3-month return | −2.9% | −2.9% |
| Year to date | −5.0% | −4.7% |
| 1-year return | −5.6% | −5.6% |
| 30-day volatility | 6.7% | 6.6% |
| Worst drawdown, 1 year | −8.1% | −8.0% |
| Trailing 12-month yield | 4.50% | 4.30% |
| Holdings | 10,818 | 2,763 |
| Top 10 weight | 6.0% | 7.2% |
| Look-through P/E | — | — |
| Holdings vs fair value | — | — |
| Holdings above 200-day average | — | — |
| Net flow, latest 3 reported months | −$179M thru May 2026 | +$196M thru Jun 2026 |
| 30-day implied volatility | 8.3% | 48.5% |
| Holdings as of | as of Oct 19, 2026issuer data | as of Oct 19, 2026issuer data |
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
27% of MBB · 43% of SPMB| Holding | MBB | SPMB |
|---|---|---|
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 0.60% | 0.96% |
| FNMA 30YR UMBS, due Nov 1, 2051 | 0.45% | 0.45% |
| GNMA2 30YR, due Jan 20, 2052 | 0.33% | 0.34% |
| FNMA 30YR UMBS, due Oct 1, 2051 | 0.32% | 0.35% |
| GNMA2 30YR, due Apr 20, 2056 | 0.43% | 0.31% |
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 0.35% | 0.30% |
| GNMA2 30YR TBA, due Nov 19, 2026 | 0.62% | 0.29% |
| FHLMC 30YR UMBS SUPER, due Apr 1, 2051 | 0.51% | 0.29% |
| GNMA2 30YR, due Aug 20, 2056 | 0.27% | 0.27% |
| FNMA 30YR UMBS, due Apr 1, 2051 | 0.30% | 0.25% |
| FHLMC 30YR UMBS, due Apr 1, 2056 | 0.25% | 0.28% |
| GNMA2 30YR, due Aug 20, 2051 | 0.30% | 0.24% |
| GNMA2 30YR, due Dec 20, 2050 | 0.28% | 0.23% |
| FNMA 30YR UMBS SUPER, due Feb 1, 2052 | 0.22% | 0.42% |
| FHLMC 30YR UMBS, due May 1, 2056 | 0.21% | 1.01% |
| GNMA2 30YR, due May 20, 2051 | 0.35% | 0.21% |
| GNMA2 30YR, due Dec 20, 2051 | 0.53% | 0.19% |
| GNMA2 30YR TBA(REG C), due Nov 19, 2026 | 0.53% | 0.18% |
| GNMA2 30YR, due Mar 20, 2052 | 0.19% | 0.17% |
| GNMA2 30YR, due Apr 20, 2052 | 0.23% | 0.17% |
| GNMA2 30YR, due Feb 20, 2051 | 0.16% | 0.20% |
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 0.16% | 0.39% |
| GNMA II 30YR, due Jul 20, 2053 | 0.16% | 0.24% |
| FNMA 30YR UMBS, due Jul 1, 2051 | 0.15% | 0.28% |
| GNMA2 30YR, due Jan 20, 2052 | 0.15% | 0.23% |
Sector mix of the stock holdings
No sector breakdown: these funds hold few classified stocks.
More: full overlap table · MBB holdings · SPMB 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.