---
ticker: "MBB"
name: "iShares MBS ETF"
url: "https://etf.net/etf/MBB"
grade: "A"
score: 70
graded_at: "2026-10-12"
category: "Mortgage-Backed Securities"
category_rank: "3 of 25"
methodology: "https://etf.net/methodology"
---

# MBB: iShares MBS ETF

Grade **A**, Score 70 of 100. Rank 3 of 25 in Mortgage-Backed Securities.

Graded Oct 12, 2026.

## Grade pillars

| Pillar | Score | Category rank |
| --- | --- | --- |
| Cost | 94 | 1 of 25 |
| Mission | 53 | 8 of 20 |
| Risk | 31 | 21 of 25 |
| Tradability | 84 | 2 of 25 |
| Holdings | 78 | 6 of 25 |
| Durability | 92 | 1 of 25 |

## Top holdings

The fund holds 10844 positions. These are the largest 30, by weight.

| # | Ticker | Name | Weight |
| --- | --- | --- | --- |
| 1 | — | BlackRock Cash Class Inst Sl Agency | 4.69% |
| 2 | — | Fhlmc 30YR Umbs Super 2.00% 05/01/2051 | 1.03% |
| 3 | — | GNMA2 30YR Tba(Reg C) 6.00% 10/20/2026 | 0.68% |
| 4 | — | Umbs 30YR Tba(Reg A) 5.50% 11/12/2026 | 0.59% |
| 5 | — | GNMA2 30YR 5.00% 11/20/2054 | 0.58% |
| 6 | — | GNMA2 30YR Tba(Reg C) 5.50% 10/20/2026 | 0.57% |
| 7 | — | GNMA2 30YR 2.00% 10/20/2051 | 0.53% |
| 8 | — | GNMA2 30YR 2.00% 12/20/2051 | 0.52% |
| 9 | — | Fnma 30YR Umbs 2.00% 12/01/2051 | 0.52% |
| 10 | — | GNMA2 30YR 2.50% 07/20/2051 | 0.51% |
| 11 | — | Fhlmc 30YR Umbs Super 2.00% 04/01/2051 | 0.49% |
| 12 | — | Fnma 30YR Umbs 2.00% 11/01/2051 | 0.44% |
| 13 | — | GNMA2 30YR 5.00% 04/20/2056 | 0.43% |
| 14 | — | GNMA2 30YR 5.50% 09/20/2053 | 0.40% |
| 15 | — | GNMA2 30YR 5.50% 09/20/2055 | 0.39% |
| 16 | — | GNMA2 30YR 2.50% 05/20/2051 | 0.35% |
| 17 | — | Umbs 30YR Tba(Reg A) 5.00% 11/12/2026 | 0.35% |
| 18 | — | Fnma 30YR Umbs Super 2.00% 04/01/2052 | 0.32% |
| 19 | — | Fnma 30YR Umbs 2.00% 03/01/2051 | 0.32% |
| 20 | — | GNMA2 30YR 2.00% 01/20/2052 | 0.32% |
| 21 | — | GNMA2 30YR 5.00% 05/20/2056 | 0.31% |
| 22 | — | Fnma 30YR Umbs 2.00% 10/01/2051 | 0.31% |
| 23 | — | GNMA2 30YR 2.50% 08/20/2051 | 0.30% |
| 24 | — | Fnma 30YR Umbs 2.00% 04/01/2051 | 0.29% |
| 25 | — | Fnma 30YR Umbs 5.50% 09/01/2056 | 0.27% |
| 26 | — | GNMA2 30YR 2.00% 12/20/2050 | 0.27% |
| 27 | — | Fnma 30YR Umbs 2.00% 02/01/2051 | 0.27% |
| 28 | — | GNMA2 30YR 2.50% 12/20/2051 | 0.27% |
| 29 | — | GNMA2 30YR 5.50% 08/20/2056 | 0.27% |
| 30 | — | Umbs 30YR Tba(Reg A) 6.00% 11/12/2026 | 0.26% |

Source: etf.net, https://etf.net/etf/MBB. Please cite the page URL.