ETF Overlap Tool
Enter up to six ETFs to see how much of each is the same securities. Overlap by weight is the sum, over every holding two funds share, of the smaller of the two weights: 100% means identical portfolios, 0% means nothing in common.
Overlap by weight
47 holdings in all 2 funds| Fund | MBBA | SPMB | Positions | Holdings |
|---|---|---|---|---|
| MBBAiShares Mortgage-Backed Securities Active ETF | — | 6% 47 shared |
670 | as of Oct 20, 2026issuer data |
| SPMBState Street SPDR Portfolio Mortgage Backed Bond ETF | 6% 47 shared | — | 2,761 | as of Oct 20, 2026issuer data |
Each cell: overlap by weight, and how many positions the two funds share. Stocks, funds and bonds are compared, a bond by its own identifier and a Treasury bill by its maturity date; cash and derivatives are not, and a fund that is partly either shows how much of it is compared.
Held by both funds
6.4% common weight| Holding | MBBA | SPMB | Smallest |
|---|---|---|---|
| FHLMC 30YR UMBS, due May 1, 2056 | 1.01% | 1.01% | 1.01% |
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 11.34% | 0.96% | 0.96% |
| FHLMC 30YR UMBS SUPER, due Nov 1, 2051 | 0.85% | 0.41% | 0.41% |
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 6.18% | 0.39% | 0.39% |
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 1.33% | 0.33% | 0.33% |
| GNMA2 30YR TBA, due Nov 19, 2026 | 1.43% | 0.29% | 0.29% |
| FHLMC 30YR UMBS SUPER, due Apr 1, 2051 | 0.28% | 0.29% | 0.28% |
| FNMA 30YR UMBS, due Apr 1, 2051 | 0.23% | 0.25% | 0.23% |
| GNMA2 30YR TBA(REG C), due Nov 19, 2026 | 2.67% | 0.18% | 0.18% |
| GNMA2 30YR, due Apr 20, 2052 | 1.58% | 0.17% | 0.17% |
| FNMA 30YR UMBS, due Jul 1, 2051 | 0.16% | 0.18% | 0.16% |
| GNMA2 30YR TBA(REG C), due Nov 19, 2026 | 1.65% | 0.14% | 0.14% |
| GNMA2 30YR TBA(REG C), due Nov 19, 2026 | 0.83% | 0.14% | 0.14% |
| GNMA2 30YR, due Dec 20, 2055 | 0.37% | 0.13% | 0.13% |
| GNMA2 30YR TBA(REG C), due Nov 19, 2026 | 0.97% | 0.13% | 0.13% |
| UMBS 15YR TBA(REG B), due Nov 17, 2026 | 2.54% | 0.11% | 0.11% |
| GNMA2 30YR, due Jan 20, 2050 | 0.17% | 0.11% | 0.11% |
| FHLMC 30YR UMBS SUPER, due Nov 1, 2054 | 0.10% | 0.21% | 0.10% |
| GNMA2 30YR TBA(REG C), due Nov 19, 2026 | 4.80% | 0.10% | 0.10% |
| GNMA2 30YR TBA(REG C), due Nov 19, 2026 | 0.66% | 0.10% | 0.10% |
| GNMA2 30YR TBA(REG C), due Nov 19, 2026 | 1.95% | 0.10% | 0.10% |
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 3.58% | 0.09% | 0.09% |
| UMBS 15YR TBA(REG B), due Nov 17, 2026 | 0.16% | 0.06% | 0.06% |
| FNMA 30YR UMBS, due Sep 1, 2052 | 0.17% | 0.05% | 0.05% |
| FNMA 30YR UMBS, due Apr 1, 2051 | 0.16% | 0.05% | 0.05% |
| FNMA 30YR UMBS, due Oct 1, 2052 | 0.05% | 0.18% | 0.05% |
| FHLMC 30YR UMBS SUPER, due Oct 1, 2052 | 0.05% | 0.08% | 0.05% |
| FNMA 30YR UMBS, due Jul 1, 2052 | 0.04% | 0.17% | 0.04% |
| FHLMC 30YR UMBS SUPER, due Jan 1, 2053 | 1.85% | 0.04% | 0.04% |
| FNMA 30YR UMBS, due Jun 1, 2052 | 0.04% | 0.22% | 0.04% |
| UMBS 15YR TBA(REG B), due Nov 17, 2026 | 1.13% | 0.04% | 0.04% |
| UMBS 30YR TBA(REG A), due Nov 12, 2026 | 0.04% | 0.12% | 0.04% |
| FNMA 30YR UMBS, due Apr 1, 2052 | 0.04% | 0.12% | 0.04% |
| FNMA 30YR UMBS SUPER, due Mar 1, 2051 | 0.04% | 0.13% | 0.04% |
| GNMA2 30YR, due Sep 20, 2051 | 0.04% | 0.10% | 0.04% |
| GNMA2 30YR TBA(REG C), due Nov 19, 2026 | 1.26% | 0.03% | 0.03% |
| UMBS 15YR TBA(REG B), due Nov 17, 2026 | 0.43% | 0.03% | 0.03% |
| UMBS 15YR TBA(REG B), due Nov 17, 2026 | 0.90% | 0.03% | 0.03% |
| FHLMC 30YR UMBS SUPER, due Apr 1, 2052 | 0.04% | 0.03% | 0.03% |
| GNMA2 30YR, due Dec 20, 2051 | 0.54% | 0.02% | 0.02% |
| FHLMC 30YR UMBS SUPER, due Jan 1, 2053 | 0.14% | 0.01% | 0.01% |
| FHLMC 30YR UMBS SUPER, due May 1, 2052 | 0.53% | 0.01% | 0.01% |
| GNMA2 30YR, due Jan 20, 2050 | 0.30% | 0.01% | 0.01% |
| GNMA2 30YR, due May 20, 2050 | 0.01% | 0.00% | 0.00% |
| UMBS 15YR TBA(REG B), due Nov 17, 2026 | 0.18% | 0.00% | 0.00% |
| FGOLD 20YR, due Jul 1, 2035 | 0.04% | 0.00% | 0.00% |
| GNMA2 30YR, due Jul 20, 2048 | 0.00% | 0.00% | 0.00% |
Reading overlap
Two funds with 80% overlap move together and holding both mostly doubles one exposure and both fees. Low overlap is not the same as diversification: two funds can share no holdings and still be driven by the same factor. To see what a whole portfolio owns, use the portfolio x-ray.
Holdings come from each issuer's daily file where we have one and otherwise from the fund's latest SEC filing, so the two sides of a comparison can be from different dates. The table shows each fund's date.
Bond funds are matched issue by issue: two Treasury funds overlap only where they hold the same bill, note or bond. A fund of short-dated bills replaces its whole portfolio every few months, so holdings from an older filing may have matured; the table says when they have.
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.