IUSBvsSPABETF Comparison
VS
iShares Core Total USD Bond Market ETF (IUSB) and State Street SPDR Portfolio Aggregate Bond ETF (SPAB) belong to the same industry segment: US Aggregate Bonds. Both ETFs have the same top 3 sector exposures: Sovereign, Finance and Industrials. IUSB is more expensive with a Total Expense Ratio (TER) of 0.06%, versus 0.03% for SPAB. IUSB is down -1.23% year-to-date (YTD) with +$10.90B in YTD flows. SPAB performs worse with -1.49% YTD performance, and +$1.03B in YTD flows. Run a side-by-side ETF comparison of IUSB and SPAB below, and assess how they stack up in performance, liquidity, risk, exposure, holdings, and more, helping you select the best ETF for your investments.
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IUSB vs SPAB performance and flow charts
Performance
Cumulative Flows
Historic performance and flows
Data as of 09/16/2026
| 1M | 3M | YTD | 1Y | 3Y | 5Y | ||
|---|---|---|---|---|---|---|---|
| Perf. | IUSB SPAB | -1.14%-1.16% | -2.08%-2.20% | -1.23%-1.49% | -0.61%-1.01% | +13.91%+12.38% | -0.93%-2.84% |
| Flows | IUSB SPAB | +$1.01B-$231M | +$2.74B+$586M | +$10.90B+$1.03B | +$11.03B+$1.72B | +$22.36B+$3.29B | +$32.02B+$4.80B |
Volatility and drawdown
| 3M | 1Y | 3Y | 5Y | ||
|---|---|---|---|---|---|
| Volatility | IUSB SPAB | +3.63%+3.89% | +3.45%+3.66% | +4.72%+5.08% | +5.53%+5.96% |
| Max drawdown | IUSB SPAB | -2.42%-2.58% | -2.91%-3.26% | -4.33%-4.87% | -17.80%-17.79% |
| Max drawdown duration | IUSB SPAB | 79d79d | 199d199d | 280d284d | 1484d1617d |
Trading data
IUSB | SPAB | |
Last sale 9/17/2026 at 4:45 PM | $44.90 | $24.80 |
| Previous close 09/16/2026 | $44.71 | $24.71 |
| Consolidated volume 09/16/2026 | ||
| Average volume 30 days | ||
| Average discount or premium 30 days | ||
| Average Bid/Ask spread 30 days |
Replication quality
Data as of August 31, 2026
1-year trailing difference
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IUSB | SPAB | |
|---|---|---|
| Tracking error | ||
| Tracking difference | ||
| 1 year cumulative return difference | ||
| Best | ||
| Worst | ||
| Daily return difference | ||
| Average | ||
| Worst | ||
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Main metrics
Last update 9/17/2026 at 4:45 PM
Live
Closed
IUSB | SPAB | |
|---|---|---|
| Last price | $44.90 | $24.80 |
| 1D performance | +0.41% | +0.36% |
| AuM | $43.68 B | $9.91 B |
| E/R | 0.06% | 0.03% |
Characteristics
IUSB | SPAB | |
|---|---|---|
| Management strategy | Passive | Passive |
| Provider | iShares | State Street Investment Management |
| Benchmark | Bloomberg U.S. Universal Index | Bloomberg US Aggregate Bond Index |
| N° of holdings | 16285 | 7063 |
| Asset class | Bonds | Bonds |
| Trailing 12m distribution yield | Join | Join |
| Inception date | June 10, 2014 | May 23, 2007 |
| ESG | No | No |
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Exposure
Countries
IUSB
USA
73.5%
Other
26.5%
SPAB
USA
75.76%
Other
24.24%
Sectors
IUSB
Sovereign
43.13%
Finance
13.46%
Other
43.41%
SPAB
Sovereign
46.7%
Finance
10.36%
Industrials
9.6%
Other
33.34%
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Diversification
IUSB
Total weight of top 15 holdings out of 15
9.25%
SPAB
Total weight of top 15 holdings out of 15
6.21%
Top 15 holdings
Data as of July 31, 2026
IUSB
BlackRock Liquidity TempCash
4.35%
US01F0206874
0.42%
USA, Notes 4.375% 31dec2029, USD (AH-2029)
0.38%
USA, Notes 4.375% 15may2036, USD (C-2036)
0.37%
USA, Notes 4% 15feb2034, USD (B-2034)
0.37%
USA, Notes 4.625% 15feb2035, USD (B-2035)
0.35%
USA, Notes 4.25% 15aug2035, USD (E-2035)
0.35%
USA, Notes 4.375% 15may2034, USD (C-2034)
0.34%
USA, Notes 4.25% 15nov2034, USD (F-2034)
0.34%
USA, Notes 4.125% 15feb2036, USD (B-2036)
0.34%
USA, Notes 3.875% 15aug2034, USD (E-2034)
0.34%
USA, Notes 4.25% 15may2035, USD (C-2035)
0.33%
USA, Notes 2.75% 15aug2032, USD (E-2032)
0.33%
USA, Notes 4% 15nov2035, USD (F-2035)
0.33%
US01F0426811
0.31%
SPAB
USA, Notes 3.5% 15dec2028, USD (AV-2028)
0.77%
USA, Notes 4% 15nov2035, USD (F-2035)
0.46%
USA, Notes 4.375% 30nov2028, USD (AG-2028)
0.43%
USA, Notes 3.5% 31jan2028, USD (U-2028)
0.42%
USA, Notes 3.875% 31mar2031, USD (W-2031)
0.41%
USA, Notes 3.375% 31dec2027, USD (BM-2027)
0.39%
USA, Notes 4.25% 15nov2034, USD (F-2034)
0.39%
USA, Notes 4.25% 15aug2035, USD (E-2035)
0.38%
USA, Notes 4.375% 15may2036, USD (C-2036)
0.38%
US01F0526800
0.38%
USA, Notes 4.375% 15may2034, USD (C-2034)
0.36%
USA, Notes 3.875% 15aug2033, USD (E-2033)
0.36%
USA, Notes 4.5% 15nov2033, USD (F-2033)
0.36%
USA, Notes 4.625% 15feb2035, USD (B-2035)
0.36%
USA, Notes 3.875% 15aug2034, USD (E-2034)
0.36%
Frequently asked questions about IUSB and SPAB
How have the IUSB and SPAB ETFs performed in 2026?
As of September 16, 2026, IUSB is down -1.23% year-to-date (YTD), while SPAB has lost -1.49%. That puts IUSB better performer ahead so far this year.
Which ETF is attracting more investor money: IUSB or SPAB?
Year-to-date, the IUSB ETF saw +$10.90B in flows, compared to +$1.03B for SPAB.
Which ETF is more volatile: IUSB or SPAB?
Over the past year, IUSB had a volatility of 3.45%, while SPAB experienced 3.66%.
Which ETF is bigger: IUSB or SPAB?
As of September 16, 2026, IUSB holds $43.68 B in assets under management (AUM), while SPAB manages $9.91 B.
What sectors do the IUSB and SPAB ETFs invest in?
IUSB leans toward sectors like Sovereign and Finance. Meanwhile, SPAB focuses on Sovereign, Finance and Industrials.
What are the top holdings of the IUSB ETF and SPAB ETF?
IUSB top holdings include BlackRock Liquidity TempCash, US01F0206874 and USA, Notes 4.375% 31dec2029, USD (AH-2029). SPAB holds in its top three: USA, Notes 3.5% 15dec2028, USD (AV-2028), USA, Notes 4% 15nov2035, USD (F-2035) and USA, Notes 4.375% 30nov2028, USD (AG-2028).
Which ETF is more diversified: IUSB or SPAB?
IUSB holds 18026 securities with 9.25% of its assets in the top 15. SPAB has 8468 securities and a top 15 weight of 6.21%.
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