AGG vs MBB: Holdings Overlap
AGGiShares Core U.S. Aggregate Bond ETF
iShares · 13266 holdings · $137.7B · as of 2026-05-31
iShares · 11144 holdings · $39.1B · as of 2026-05-31
How similar are AGG and MBB?
iShares Core U.S. Aggregate Bond ETF (AGG, by iShares) holds 13266 positions; iShares MBS ETF (MBB, by iShares) holds 11144. They have 1878 holdings in common, and by portfolio weight the two funds are 16.7% identical. In practical terms the pair is lightly overlapping, with most of each portfolio distinct.
- Overlap by Weight
- 16.7%Sum of the smaller weight of each shared holding
- Shared Holdings
- 1878AGG holds 13266 · MBB holds 11144
- Weight in Shared Holdings
- AGG 18%·MBB 57%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 AGG
11388 of 13266 positions (80.5% of the fund) are not held by MBB. Showing the top 30 by weight.
- U.S. Treasury Notes0.42%
- U.S. Treasury Notes0.41%
- U.S. Treasury Notes0.41%
- U.S. Treasury Notes0.40%
- U.S. Treasury Notes0.40%
- U.S. Treasury Notes0.39%
Only in MBB
9266 of 11144 positions (40.9% of the fund) are not held by AGG. Showing the top 30 by weight.
- Fannie Mae Pool0.33%
- Fannie Mae Pool0.28%
- Fannie Mae Pool0.23%
- Fannie Mae Pool0.21%
- Freddie Mac Pool0.20%
- Freddie Mac Pool0.19%
Performance
| Fund | 1M | YTD | 1Y | 3Y (ann.) | 5Y (ann.) | 10Y (ann.) | Yield |
|---|---|---|---|---|---|---|---|
| AGG | -0.3% | +0.0% | +2.4% | +4.2% | -0.2% | +1.4% | 4.04% |
| 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 AGG vs MBB →
Shared Holdings(1878)
The top 10 shared positions account for 9% of the overlap, led by Fannie Mae Pool, Uniform Mortgage-Backed Security, TBA and Uniform Mortgage-Backed Security, TBA.
| Fannie Mae Pool | 0.22% | 0.31% | 0.22% |
|---|---|---|---|
| Uniform Mortgage-Backed Security, TBA | 0.20% | 0.34% | 0.20% |
| Uniform Mortgage-Backed Security, TBA | 0.16% | 0.64% | 0.16% |
| Ginnie Mae | 0.14% | 0.95% | 0.14% |
| Freddie Mac Pool | 0.14% | 0.18% | 0.14% |
| Ginnie Mae II Pool | 0.14% | 0.35% | 0.14% |
| Uniform Mortgage-Backed Security, TBA | 0.14% | 0.83% | 0.14% |
| Fannie Mae Pool | 0.13% | 0.44% | 0.13% |
| Fannie Mae Pool | 0.13% | 0.52% | 0.13% |
| Ginnie Mae II Pool | 0.12% | 0.20% | 0.12% |
| Ginnie Mae | 0.12% | 0.67% | 0.12% |
| Fannie Mae Pool | 0.12% | 0.22% | 0.12% |
| Uniform Mortgage-Backed Security, TBA | 0.12% | 0.26% | 0.12% |
| Ginnie Mae II Pool | 0.12% | 0.45% | 0.12% |
| Ginnie Mae II Pool | 0.11% | 0.19% | 0.11% |
| Ginnie Mae II Pool | 0.11% | 0.30% | 0.11% |
| Ginnie Mae II Pool | 0.11% | 0.53% | 0.11% |
| Ginnie Mae II Pool | 0.11% | 0.16% | 0.11% |
| Fannie Mae Pool | 0.11% | 0.17% | 0.11% |
| Ginnie Mae II Pool | 0.11% | 0.55% | 0.11% |
| Ginnie Mae | 0.10% | 0.18% | 0.10% |
| Ginnie Mae | 0.10% | 0.23% | 0.10% |
| Ginnie Mae II Pool | 0.10% | 0.28% | 0.10% |
| Ginnie Mae II Pool | 0.10% | 0.36% | 0.10% |
| Ginnie Mae II Pool | 0.09% | 0.28% | 0.09% |
Showing the top 250 of 1878 shared holdings by overlap weight.
Frequently Asked Questions
How much do AGG and MBB overlap?
AGG and MBB overlap by 16.7% of portfolio weight. They share 1878 holdings (AGG holds 13266 positions and MBB holds 11144), based on each fund's latest SEC-reported holdings.
Is it redundant to own both AGG and MBB?
The two portfolios are 16.7% identical by weight. Owning both is not redundant. Most of each portfolio is distinct, so the funds can serve different roles.
What are the biggest shared holdings of AGG and MBB?
The largest positions held by both funds are Fannie Mae Pool, Uniform Mortgage-Backed Security, TBA, Uniform Mortgage-Backed Security, TBA, Ginnie Mae and Freddie Mac Pool. Together the top 10 shared positions account for 9% of the total overlap.
What does AGG own that MBB doesn't?
11388 positions (80.5% of AGG) are unique to AGG, led by U.S. Treasury Notes, U.S. Treasury Notes and U.S. Treasury Notes. In the other direction, 9266 positions (40.9% of MBB) are unique to MBB.