IUSB vs ISTB: Holdings Overlap
IUSBiShares Core Universal USD Bond ETF
iShares · 17783 holdings · $43.2B · as of 2026-04-30
ISTBiShares Core 1-5 Year USD Bond ETF
iShares · 7059 holdings · $5.1B · as of 2026-04-30
How similar are IUSB and ISTB?
iShares Core Universal USD Bond ETF (IUSB, by iShares) holds 17783 positions; iShares Core 1-5 Year USD Bond ETF (ISTB, by iShares) holds 7059. They have 6880 holdings in common, and by portfolio weight the two funds are 37.0% identical. In practical terms the pair is moderately overlapping; they share a meaningful core, but each fund adds distinct exposure.
- Overlap by Weight
- 37.0%Sum of the smaller weight of each shared holding
- Shared Holdings
- 6880IUSB holds 17783 · ISTB holds 7059
- Weight in Shared Holdings
- IUSB 39%·ISTB 97%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 IUSB
10903 of 17783 positions (59.6% of the fund) are not held by ISTB. Showing the top 30 by weight.
- U.S. Treasury Notes0.37%
- U.S. Treasury Notes0.37%
- U.S. Treasury Notes0.37%
- U.S. Treasury Notes0.36%
- U.S. Treasury Notes0.36%
- U.S. Treasury Notes0.36%
Only in ISTB
179 of 7059 positions (2.0% of the fund) are not held by IUSB. Showing the top 30 by weight.
- Freddie Mac Multifamily Structured Pass Through Certificates0.21%
- Freddie Mac Pool0.12%
- Freddie Mac Multifamily Structured Pass Through Certificates0.07%
- Freddie Mac Pool0.05%
- Wells Fargo Commercial Mortgage Trust 2024-5C10.04%
- Kommunalbanken AS0.04%
Performance
| Fund | 1M | YTD | 1Y | 3Y (ann.) | 5Y (ann.) | 10Y (ann.) | Yield |
|---|---|---|---|---|---|---|---|
| IUSB | -0.2% | +0.3% | +2.8% | +4.7% | +0.2% | +1.8% | 4.28% |
| ISTB | +0.3% | +1.0% | +3.0% | +5.0% | +1.9% | +2.3% | 4.27% |
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 IUSB vs ISTB →
Shared Holdings(6880)
The top 10 shared positions account for 8% of the overlap, led by U.S. Treasury Notes, U.S. Treasury Notes and U.S. Treasury Notes.
| U.S. Treasury Notes | 0.37% | 0.99% | 0.37% |
|---|---|---|---|
| U.S. Treasury Notes | 0.34% | 0.96% | 0.34% |
| U.S. Treasury Notes | 0.33% | 0.98% | 0.33% |
| U.S. Treasury Notes | 0.32% | 0.67% | 0.32% |
| U.S. Treasury Notes | 0.31% | 0.57% | 0.31% |
| U.S. Treasury Notes | 0.30% | 0.53% | 0.30% |
| U.S. Treasury Notes | 0.29% | 0.64% | 0.29% |
| U.S. Treasury Notes | 0.28% | 0.89% | 0.28% |
| U.S. Treasury Notes | 0.28% | 0.86% | 0.28% |
| U.S. Treasury Notes | 0.27% | 0.68% | 0.27% |
| U.S. Treasury Notes | 0.27% | 0.46% | 0.27% |
| U.S. Treasury Notes | 0.26% | 0.83% | 0.26% |
| U.S. Treasury Notes | 0.29% | 0.26% | 0.26% |
| U.S. Treasury Notes | 0.25% | 0.29% | 0.25% |
| U.S. Treasury Notes | 0.24% | 0.60% | 0.24% |
| U.S. Treasury Notes | 0.24% | 0.50% | 0.24% |
| U.S. Treasury Notes | 0.24% | 0.45% | 0.24% |
| U.S. Treasury Notes | 0.23% | 0.61% | 0.23% |
| U.S. Treasury Notes | 0.23% | 0.34% | 0.23% |
| U.S. Treasury Notes | 0.23% | 0.47% | 0.23% |
| U.S. Treasury Notes | 0.22% | 0.67% | 0.22% |
| U.S. Treasury Notes | 0.22% | 0.58% | 0.22% |
| U.S. Treasury Notes | 0.22% | 0.81% | 0.22% |
| U.S. Treasury Notes | 0.22% | 0.27% | 0.22% |
| U.S. Treasury Notes | 0.21% | 0.51% | 0.21% |
Showing the top 250 of 6880 shared holdings by overlap weight.
Frequently Asked Questions
How much do IUSB and ISTB overlap?
IUSB and ISTB overlap by 37.0% of portfolio weight. They share 6880 holdings (IUSB holds 17783 positions and ISTB holds 7059), based on each fund's latest SEC-reported holdings.
Is it redundant to own both IUSB and ISTB?
The two portfolios are 37.0% identical by weight. Owning both is defensible: they share a meaningful core, but each fund adds exposure the other lacks.
What are the biggest shared holdings of IUSB and ISTB?
The largest positions held by both funds are U.S. Treasury Notes, U.S. Treasury Notes, U.S. Treasury Notes, U.S. Treasury Notes and U.S. Treasury Notes. Together the top 10 shared positions account for 8% of the total overlap.
What does IUSB own that ISTB doesn't?
10903 positions (59.6% of IUSB) are unique to IUSB, led by U.S. Treasury Notes, U.S. Treasury Notes and U.S. Treasury Notes. In the other direction, 179 positions (2.0% of ISTB) are unique to ISTB.