MBB vs PMBS
iShares MBS ETF against PIMCO Mortgage-Backed Securities Active Exchange-Traded Fund: cost, size, returns, what they hold and how much of it is the same.
Overlap by weight
4%
56 shared positions
Fee gap
67 bp
MBB is cheaper
1-year return gap
1.0 pts
MBB is ahead
Larger fund
MBB
$35.2B
Side by side
| MBB | PMBS | |
|---|---|---|
| Fund | iShares MBS ETF | PIMCO Mortgage-Backed Securities Active Exchange-Traded Fund |
| Issuer | iShares | PIMCO |
| Category | Mortgage & Securitized | Mortgage & Securitized |
| Expense ratio | 0.04% | 0.71% |
| Assets | $35.2B | $1.4B |
| Average daily dollar volume | $690M | $13M |
| Listed | Mar 13, 2007 | Jul 31, 1997 |
| FrenzyCap score | 98 | 51 |
| 1-month return | −1.0% | −1.8% |
| 3-month return | −2.5% | −3.7% |
| Year to date | −4.9% | −6.1% |
| 1-year return | −5.7% | −6.6% |
| 30-day volatility | 6.7% | 7.0% |
| Worst drawdown, 1 year | −8.1% | −9.5% |
| Trailing 12-month yield | 4.50% | 4.97% |
| Holdings | 10,818 | 1,305 |
| Top 10 weight | 6.0% | 63.1% |
| Look-through P/E | — | — |
| Holdings vs fair value | — | — |
| Holdings above 200-day average | — | — |
| Net flow, latest 3 reported months | −$179M thru May 2026 | — |
| 30-day implied volatility | 7.8% | — |
| Holdings as of | as of Oct 20, 2026issuer data | as of Oct 20, 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
4% of MBB · 41% of PMBS| Holding | MBB | PMBS |
|---|---|---|
| GNMA2 30YR TBA, due Nov 19, 2026 | 0.62% | 1.55% |
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 0.60% | 1.20% |
| GNMA2 30YR TBA(REG C), due Nov 19, 2026 | 0.53% | 4.31% |
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 0.35% | 1.99% |
| UMBS 15YR TBA(REG B), due Nov 17, 2026 | 0.26% | 1.07% |
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 0.22% | 3.70% |
| GNMA2 30YR TBA(REG C), due Nov 19, 2026 | 0.22% | 0.99% |
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 0.16% | 5.94% |
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 0.12% | 6.48% |
| FHLMC 30YR UMBS SUPER, due Oct 1, 2054 | 0.12% | 0.64% |
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 0.11% | 1.43% |
| UMBS 15YR TBA(REG B), due Nov 17, 2026 | 0.08% | 0.33% |
| FNMA 30YR UMBS, due Mar 1, 2054 | 0.06% | 0.23% |
| GNMA2 30YR TBA(REG C), due Nov 19, 2026 | 0.06% | 1.70% |
| GNMA2 30YR, due Oct 20, 2051 | 0.06% | 3.64% |
| UMBS 15YR TBA(REG B), due Nov 17, 2026 | 0.04% | 0.07% |
| UMBS 15YR TBA(REG B), due Nov 17, 2026 | 0.04% | 1.01% |
| GNMA2 30YR TBA(REG C), due Nov 19, 2026 | 0.03% | 1.66% |
| GNMA2 30YR, due Aug 20, 2055 | 0.03% | 0.18% |
| UMBS 15YR TBA(REG B), due Nov 17, 2026 | 0.01% | 0.07% |
| GNMA2 30YR, due Feb 20, 2048 | 0.01% | 0.01% |
| FHLMC 30YR UMBS, due Sep 1, 2053 | 0.04% | 0.01% |
| FNMA 30YR UMBS, due May 1, 2051 | 0.01% | 0.17% |
| GNMA2 30YR, due Nov 20, 2048 | 0.00% | 0.01% |
| GNMA2 30YR, due Feb 20, 2049 | 0.00% | 0.01% |
Sector mix of the stock holdings
No sector breakdown: these funds hold few classified stocks.
More: full overlap table · MBB holdings · PMBS 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.