FBND vs MBB: Holdings Overlap
Fidelity · 4503 holdings · $27.3B · as of 2026-05-31
iShares · 11144 holdings · $39.1B · as of 2026-05-31
How similar are FBND and MBB?
Fidelity Total Bond ETF (FBND, by Fidelity) holds 4503 positions; iShares MBS ETF (MBB, by iShares) holds 11144. They have 157 holdings in common, and by portfolio weight the two funds are 4.8% identical. In practical terms the pair is essentially distinct, holding almost none of the same securities.
- Overlap by Weight
- 4.8%Sum of the smaller weight of each shared holding
- Shared Holdings
- 157FBND holds 4503 · MBB holds 11144
- Weight in Shared Holdings
- FBND 7%·MBB 12%Share of each fund's weight in stocks both funds own
Based on each fund's latest official holdings. How is this calculated?
What makes each fund different
Only in FBND
4346 of 4503 positions (97.9% of the fund) are not held by MBB. Showing the top 30 by weight.
- U.S. Treasury Notes2.34%
- U.S. Treasury Notes2.21%
- U.S. Treasury Notes2.17%
- U.S. Treasury Notes1.81%
- U.S. Treasury Bonds1.53%
- U.S. Treasury Notes1.49%
Only in MBB
10987 of 11144 positions (86.0% of the fund) are not held by FBND. Showing the top 30 by weight.
- Ginnie Mae II Pool0.55%
- Ginnie Mae II Pool0.54%
- Fannie Mae Pool0.52%
- Fannie Mae Pool0.44%
- Ginnie Mae II Pool0.41%
- Ginnie Mae II Pool0.36%
Performance
| Fund | 1M | YTD | 1Y | 3Y (ann.) | 5Y (ann.) | 10Y (ann.) | Yield |
|---|---|---|---|---|---|---|---|
| FBND | -0.2% | +0.3% | +2.8% | +4.9% | +0.5% | +2.3% | 4.74% |
| MBB | -0.2% | +0.4% | +3.9% | +4.7% | +0.3% | +1.2% | 4.33% |
Total returns including dividends, from adjusted daily closes as of 2026-08-07. 3Y/5Y/10Y are annualized. Yield is trailing-12-month distributions over the last close. Past performance does not predict future results.
Project the growth of $10,000 in FBND vs MBB →
Shared Holdings(157)
The top 10 shared positions account for 78% of the overlap, led by Ginnie Mae, Ginnie Mae and Uniform Mortgage-Backed Security, TBA.
| Ginnie Mae | 1.14% | 0.95% | 0.95% |
|---|---|---|---|
| Ginnie Mae | 0.89% | 0.67% | 0.67% |
| Uniform Mortgage-Backed Security, TBA | 0.73% | 0.64% | 0.64% |
| Ginnie Mae | 0.41% | 0.46% | 0.41% |
| Uniform Mortgage-Backed Security, TBA | 0.44% | 0.34% | 0.34% |
| Uniform Mortgage-Backed Security, TBA | 0.26% | 0.83% | 0.26% |
| Government National Mortgage Association | 0.23% | 0.45% | 0.23% |
| Uniform Mortgage-Backed Securities | 0.10% | 0.30% | 0.10% |
| Ginnie Mae II Pool | 0.18% | 0.09% | 0.09% |
| Freddie Mac Pool | 0.08% | 0.22% | 0.08% |
| Uniform Mortgage-Backed Securities | 0.08% | 0.10% | 0.08% |
| Government National Mortgage Association | 0.07% | 0.27% | 0.07% |
| Uniform Mortgage-Backed Security, TBA | 0.14% | 0.07% | 0.07% |
| Ginnie Mae II Pool | 0.06% | 0.06% | 0.06% |
| Fannie Mae Pool | 0.05% | 0.05% | 0.05% |
| Government National Mortgage Association | 0.04% | 0.06% | 0.04% |
| Government National Mortgage Association | 0.04% | 0.12% | 0.04% |
| Freddie Mac Pool | 0.11% | 0.04% | 0.04% |
| Government National Mortgage Association | 0.05% | 0.03% | 0.03% |
| Uniform Mortgage-Backed Security, TBA | 0.13% | 0.03% | 0.03% |
| Fannie Mae Pool | 0.03% | 0.04% | 0.03% |
| Freddie Mac Pool | 0.03% | 0.05% | 0.03% |
| Uniform Mortgage-Backed Securities | 0.03% | 1.05% | 0.03% |
| Uniform Mortgage-Backed Securities | 0.15% | 0.03% | 0.03% |
| Government National Mortgage Association | 0.03% | 0.28% | 0.03% |
Frequently Asked Questions
How much do FBND and MBB overlap?
FBND and MBB overlap by 4.8% of portfolio weight. They share 157 holdings (FBND holds 4503 positions and MBB holds 11144), based on each fund's latest SEC-reported holdings.
Is it redundant to own both FBND and MBB?
The two portfolios are 4.8% identical by weight. Owning both is genuine diversification: the funds hold almost none of the same securities.
What are the biggest shared holdings of FBND and MBB?
The largest positions held by both funds are Ginnie Mae, Ginnie Mae, Uniform Mortgage-Backed Security, TBA, Ginnie Mae and Uniform Mortgage-Backed Security, TBA. Together the top 10 shared positions account for 78% of the total overlap.
What does FBND own that MBB doesn't?
4346 positions (97.9% of FBND) are unique to FBND, led by U.S. Treasury Notes, U.S. Treasury Notes and U.S. Treasury Notes. In the other direction, 10987 positions (86.0% of MBB) are unique to MBB.