ETF comparison
AGG vs SPMB
Both US Aggregate Bond.
iShares Core U.S. Aggregate Bond ETF · State Street SPDR Portfolio Mortgage Backed Bond ETF
Holdings overlap
431 positions appear in both funds. Buying equal dollars of AGG and SPMB would leave roughly 5.5% of each dollar exposed to the same underlying securities.
Unmatched is the part of a fund's weight the other fund doesn't match: names only it holds, plus any extra weight it puts in names both funds hold.
Side by side
Sub-score comparison
Tracking quality isn't part of the composite — see what we don't score for why.
Cost difference
AGG is 1 bps cheaper than SPMB. On a $100,000 position that's about $10/yr more in fees for SPMB.
Fee figure is the annual expense charged on $100,000. To see how the gap compounds over a multi-decade holding period, open the cost calculator pre-filled with AGG vs SPMB.
Top shared holdings
431 shared in total| # | Holding | In AGG | In SPMB | Overlap |
|---|---|---|---|---|
| 1 | Fannie Mae | 0.22% | 0.37% | 0.22% |
| 2 | Government National Mortgage Association | 0.14% | 0.22% | 0.14% |
| 3 | Fannie Mae | 0.13% | 0.47% | 0.13% |
| 4 | Fannie Mae | 0.12% | 0.45% | 0.12% |
| 5 | Government National Mortgage Association | 0.12% | 0.13% | 0.12% |
| 6 | Government National Mortgage Association | 0.11% | 0.25% | 0.11% |
| 7 | Government National Mortgage Association | 0.11% | 0.20% | 0.11% |
| 8 | Government National Mortgage Association | 0.11% | 0.22% | 0.11% |
| 9 | Fannie Mae | 0.11% | 0.35% | 0.11% |
| 10 | Fannie Mae | 0.10% | 0.17% | 0.10% |
| 11 | Government National Mortgage Association | 0.10% | 0.18% | 0.10% |
| 12 | Freddie Mac | 0.14% | 0.09% | 0.09% |
Only in AGG
12,835 total- United States Treasury 0.42%
- United States Treasury 0.41%
- United States Treasury 0.41%
- United States Treasury 0.40%
- United States Treasury 0.40%
- United States Treasury 0.39%
- United States Treasury 0.39%
- United States Treasury 0.39%
- United States Treasury 0.39%
- United States Treasury 0.38%
Only in SPMB
2,268 total- Freddie Mac 1.17%
- Freddie Mac 0.76%
- UMBS, TBA 0.63%
- Freddie Mac 0.55%
- Fannie Mae 0.51%
- Fannie Mae 0.49%
- UMBS, TBA 0.46%
- UMBS, TBA 0.45%
- Government National Mortgage Association 0.44%
- Freddie Mac 0.44%
Related comparisons
More comparisons with AGG
- AGG vs CORP · PIMCO Investment Grade Corporate Bond Index Exchange-Traded Fund 5.2%
- AGG vs IEF · iShares 7-10 Year Treasury Bond ETF 5.2%
- AGG vs TLT · iShares 20+ Year Treasury Bond ETF 5.1%
- AGG vs CGCP · Capital Group Core Plus Income ETF 5.0%
- AGG vs SPSB · State Street SPDR Portfolio Short Term Corporate Bond ETF 4.7%
- AGG vs TLH · iShares 10-20 Year Treasury Bond ETF 4.5%
More comparisons with SPMB
- SPMB vs VCRB · Vanguard Core Bond ETF 4.9%
- SPMB vs EAGG · iShares ESG U.S. Aggregate Bond ETF 3.9%
- SPMB vs CGCP · Capital Group Core Plus Income ETF 3.8%
- SPMB vs IUSB · iShares Core Universal USD Bond ETF 3.6%
- SPMB vs FBND · Fidelity Total Bond ETF 2.6%
- SPMB vs PYLD · PIMCO ETF Trust - PIMCO Multisector Bond Active Exchange-Traded Fund 2.4%
Percentages are holdings overlap with the named fund.
Open AGG or SPMB at a brokerage
Both funds trade commission-free at major US brokerages.
Affiliate links — opening an account through these earns PlainIndex a one-time referral. Scoring is computed before any affiliate consideration; see our methodology and funding disclosure.
Holdings overlap is the sum of min(weight_a, weight_b) over positions
matched on ISIN (CUSIP fallback). Methodology: see
/methodology/.
Comparing two funds doesn't endorse swapping one for the other. Tax-lot history, account type, and personal goals matter — PlainIndex publishes data and methodology, not investment advice.