IWO vs XBI overlap - what they share and where they differ
IWO and XBI share 14.1% of their weight across 102 common positions, read from what each fund reported to the SEC.
Each week Ploutos reads the reported positions of the largest US equity ETFs and measures, pair by pair, the weight they share: for every stock both funds hold, the smaller of the two weights counts. Two funds tracking the same index land near 100%. A sector fund inside a broad index fund lands at roughly that sector's weight.
IWO and XBI
14.1%
102 shared positions
IWO
iShares Russell 2000 Growth ETF
Reported positions cover 100% of the fund, 1,110 positions · Jun 30, 2026
Top 10: 6.0%·Holdings of IWO
XBI
State Street(R) SPDR(R) S&P(R) Biotech ETF
Reported positions cover 100% of the fund, 149 positions · Jun 30, 2026
Top 10: 13.3%·Holdings of XBI
Reported positions cover IWO 100%, XBI 100% of each fund. An overlap cannot exceed the smaller coverage, so a low figure can mean little overlap or thin reporting.
XBI vs IWO side by side
IWOiShares Russell 2000 Growth ETF
1,110
stock positions reported to the SEC
85.5% of its weight is in 1,008 names XBI does not hold
XBIState Street(R) SPDR(R) S&P(R) Biotech ETF
149
stock positions reported to the SEC
33.4% of its weight is in 47 names IWO does not hold
Where each fund's weight sits
Largest sectors for both funds
The widest gap is Healthcare: XBI has 70.0 points more of it.
The figures side by side
| IWO | XBI | |
|---|---|---|
| Filing date | Jun 30, 2026 | Jun 30, 2026 |
| Stock positions reported | 1,110 | 149 |
| Weight of the ten largest | 6.0% | 13.3% |
| Largest position | MOG.A 0.7% | APOGEE THERAPEUTICS INC 1.5% |
| Held alone | 1,008 positions, 85.5% | 47 positions, 33.4% |
| Covered by stock positions | 100% | 100% |
Holdings they share
| Stock | In IWO | In XBI | Counted |
|---|---|---|---|
| KRYSKrystal Biotech, Inc. | 0.58% | 1.10% | 0.58% |
| PRAXPraxis Precision Medicines, Inc. | 0.51% | 1.29% | 0.51% |
| TGTXTG Therapeutics, Inc. | 0.48% | 1.09% | 0.48% |
| PTGXProtagonist Therapeutics, Inc. | 0.45% | 1.07% | 0.45% |
| ALKSAlkermes plc | 0.42% | 1.11% | 0.42% |
| NUNuvalent, Inc. | 0.40% | 0.93% | 0.40% |
| SYRESpyre Therapeutics, Inc. | 0.40% | 1.10% | 0.40% |
| COGTCogent Biosciences, Inc. | 0.39% | 1.14% | 0.39% |
| TWSTTwist Bioscience Corp. | 0.38% | 1.41% | 0.38% |
| RYTMRhythm Pharmaceuticals, Inc. | 0.37% | 1.20% | 0.37% |
What each holds alone
The heaviest positions one fund reports and the other does not.
Only in IWO
Only in XBI
Questions people ask
Is IWO the same as XBI?
14.1% of their weight sits in the same 102 holdings. IWO also reports MOG.A, BTSG, AGX, which the other does not. XBI also reports MRNA, VKTX, RVMD, which the other does not.
How is the overlap between IWO and XBI measured?
For every stock both funds report, the smaller of the two weights counts, and the sum is the overlap. The reported positions cover 100% of IWO and 100% of XBI, so the number cannot exceed the smaller coverage.
Which holds more, XBI or IWO?
IWO reports 1,110 stock positions and XBI reports 149. 85.5% of IWO's weight sits in names XBI does not hold, and 33.4% of XBI's weight in names IWO does not hold. The ten largest positions are 6.0% of IWO and 13.3% of XBI.
How do IWO and XBI differ by sector?
The widest gap is Healthcare: XBI has 70.0 points more of it. Sectors come from each holding's SIC code in its SEC record, summed by the weight the fund reports.
Where do the numbers come from?
From each fund's own N-PORT filing to the SEC, which lists every position and its weight. The comparison uses every equity position the fund reports; cash, futures and bonds are not counted, which is why a coverage figure sits next to every result. Holdings change between filings.
Add a third fund in the tool·All fund pairs
Descriptive data from public SEC filings. Nothing on this page is a recommendation to buy, sell or hold any fund or stock, and holdings change between filings.