ETF comparison
IUSB vs SPMB
Both US Aggregate Bond.
iShares Core Universal USD Bond ETF · State Street SPDR Portfolio Mortgage Backed Bond ETF
Holdings overlap
322 positions appear in both funds. Buying equal dollars of IUSB and SPMB would leave roughly 3.6% 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
SPMB is 2 bps cheaper than IUSB. On a $100,000 position that's about $20/yr more in fees for IUSB.
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 IUSB vs SPMB.
Top shared holdings
322 shared in total| # | Holding | In IUSB | In SPMB | Overlap |
|---|---|---|---|---|
| 1 | Government National Mortgage Association | 0.18% | 0.22% | 0.18% |
| 2 | Federal National Mortgage Association | 0.12% | 0.14% | 0.12% |
| 3 | Government National Mortgage Association | 0.09% | 0.25% | 0.09% |
| 4 | Federal National Mortgage Association | 0.09% | 0.17% | 0.09% |
| 5 | Federal National Mortgage Association | 0.08% | 0.14% | 0.08% |
| 6 | Federal Home Loan Mortgage Corp. | 0.08% | 0.09% | 0.08% |
| 7 | Federal Home Loan Mortgage Corp. | 0.08% | 0.29% | 0.08% |
| 8 | Government National Mortgage Association | 0.07% | 0.20% | 0.07% |
| 9 | Government National Mortgage Association | 0.07% | 0.32% | 0.07% |
| 10 | Federal National Mortgage Association | 0.07% | 0.47% | 0.07% |
| 11 | Federal National Mortgage Association | 0.06% | 0.37% | 0.06% |
| 12 | Government National Mortgage Association | 0.06% | 0.07% | 0.06% |
Only in IUSB
17,722 total- Federal National Mortgage Association or Federal Home Loan Mortgage Corp. 0.41%
- United States of America 0.37%
- United States of America 0.37%
- United States of America 0.36%
- United States of America 0.35%
- United States of America 0.34%
- United States of America 0.34%
- United States of America 0.34%
- United States of America 0.33%
- United States of America 0.33%
Only in SPMB
2,377 total- Freddie Mac 1.17%
- Fannie Mae 0.79%
- 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%
Related comparisons
More comparisons with IUSB
- IUSB vs BOND · PIMCO Active Bond Exchange-Traded Fund 3.2%
- IUSB vs PYLD · PIMCO ETF Trust - PIMCO Multisector Bond Active Exchange-Traded Fund 1.8%
- IUSB vs VUSB · Vanguard Ultra-Short Bond ETF 1.7%
- IUSB vs JPST · JPMorgan Ultra-Short Income ETF 1.1%
- IUSB vs ICSH · iShares Ultra Short Duration Bond Active ETF 0.7%
- IUSB vs PULS · PGIM Ultra Short Bond ETF 0.5%
More comparisons with SPMB
- SPMB vs FBND · Fidelity Total Bond ETF 2.6%
- SPMB vs PYLD · PIMCO ETF Trust - PIMCO Multisector Bond Active Exchange-Traded Fund 2.4%
- SPMB vs BOND · PIMCO Active Bond Exchange-Traded Fund 1.9%
- SPMB vs AGGY · WisdomTree Yield Enhanced U.S. Aggregate Bond Fund 1.2%
- SPMB vs JCPB · JPMorgan Core Plus Bond ETF 0.2%
- SPMB vs BINC · iShares Flexible Income Active ETF 0.0%
Percentages are holdings overlap with the named fund.
Open IUSB 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.