# MBB holdings by issuer, coupon and maturity MBB holds 11,146 positions from 4 issuers in its SEC Form N-PORT for the period ended 2026-05-31, filed 2026-07-24. The largest kinds are agency mortgage-backed securities at 98.1% of net assets and money market funds at 6.8%. Its debt averages a 3.67% coupon and 24.2 years to maturity, and its filing gives a duration of 5.41 years. iShares MBS ETF, fixed income ETF, iShares. Canonical page: https://tickerinside.com/etf/mbb/ Holdings from MBB's SEC Form N-PORT for the period ended 2026-05-31, filed 2026-07-24 (https://www.sec.gov/Archives/edgar/data/1100663/000141036826075251/). Licence: CC BY 4.0, attribution to TickerInside. Measurements, not investment advice. ## What does MBB hold, from its SEC Form N-PORT for the period ended 2026-05-31? | Kind of holding | Of net assets | | --- | --- | | Agency mortgage-backed securities | 98.10% | | Money market funds | 6.77% | Average coupon: 3.67%. Average maturity: 24.2 years. Duration: 5.41 years. ## Which issuers does MBB hold the most of? The largest issuer is Fannie Mae at 44.40% of net assets in 5,687 lines, then Freddie Mac at 28.14% and Ginnie Mae at 22.97%. | Rank | Issuer | Of net assets | Lines | | --- | --- | --- | --- | | 1 | Fannie Mae | 44.40% | 5687 | | 2 | Freddie Mac | 28.14% | 3375 | | 3 | Ginnie Mae | 22.97% | 2068 | | 4 | Umbs, Tba | 2.59% | 14 | ## When does MBB's debt mature? | Time to maturity | Of net assets | | --- | --- | | 1 to 3 years | 0.04% | | 3 to 5 years | 0.23% | | 5 to 7 years | 0.51% | | 7 to 10 years | 2.50% | | 10 to 20 years | 9.49% | | 20 to 30 years | 80.96% | | over 30 years | 4.36% | ## Which bond ETFs with a page here share MBB's issuers? Ranked by the lower of its issuer and maturity overlaps, AGG shares the most with MBB: 24.0% of their weight by issuer, in 4 issuers both hold, and 44.2% by time to maturity. The issuer figure counts the 1,000 largest of AGG's 1,355 issuers, 98.0% of its net assets. | ETF | Overlap by issuer | By time to maturity | Issuers in both | Average maturity | | --- | --- | --- | --- | --- | | [AGG](https://tickerinside.com/etf/agg/) | 24.0% | 44.2% | 4 | 12.5 years | | [IUSB](https://tickerinside.com/etf/iusb/) | 20.4% | 40.9% | 3 | 11.8 years | | [BND](https://tickerinside.com/etf/bnd/) | 20.3% | 40.5% | 3 | 11.7 years | | [BIV](https://tickerinside.com/etf/biv/) | 0.3% | 6.2% | 2 | 7.5 years | | [JPST](https://tickerinside.com/etf/jpst/) | 0.1% | 3.9% | 1 | 2.1 years | | [BIL](https://tickerinside.com/etf/bil/) | 0.0% | 0.0% | 0 | 0.2 years | | [BNDX](https://tickerinside.com/etf/bndx/) | 0.0% | 23.0% | 0 | 8.7 years | | [BSV](https://tickerinside.com/etf/bsv/) | 0.0% | 1.2% | 1 | 2.9 years | | [CMF](https://tickerinside.com/etf/cmf/) | 0.0% | 36.8% | 0 | 12.8 years | | [EBND](https://tickerinside.com/etf/ebnd/) | 0.0% | 24.5% | 0 | 8.8 years | | [EMLC](https://tickerinside.com/etf/emlc/) | 0.0% | 19.2% | 0 | 7.5 years | | [GOVT](https://tickerinside.com/etf/govt/) | 0.0% | 23.6% | 0 | 7.4 years | From each fund's SEC Form N-PORT: AGG, CMF, JPST and MBB for the period ended 2026-05-31, BIL, BIV, BND, BSV, EBND and EMLC 2026-06-30, BNDX, GOVT and IUSB 2026-07-31. The issuer figures count the 1,000 largest of AGG's 1,355 issuers, 98.0% of its net assets, and the 1,000 largest of IUSB's 3,459 issuers, 91.7% of its net assets, and the 1,000 largest of BND's 1,778 issuers, 97.9% of its net assets, and the 1,000 largest of BNDX's 1,354 issuers, 97.4% of its net assets. Every issuer and the largest lines: https://tickerinside.com/api/v1/etf/mbb.json Method: https://tickerinside.com/how-the-numbers-are-produced/#fixed-income ## Cite this page TickerInside, iShares MBS ETF (MBB), holdings by issuer from SEC Form N-PORT for the period ended 2026-05-31, filed 2026-07-24, https://tickerinside.com/etf/mbb/, CC BY 4.0 TickerInside (https://tickerinside.com/etf/mbb/)