IBB vs XBI ETF Comparison 2026: iShares Biotech vs SPDR S&P Biotech: AI Score, Valuation, Performance and Upside
IBB and XBI both provide biotech sector exposure, but they represent fundamentally different risk profiles within the same industry. IBB's market-cap weighting makes it a large-cap biotech ETF dominated by commercial-stage companies, while XBI's equal-weight approach gives investors levered exposure to small and mid-cap pipeline biotechs where clinical trial outcomes and M&A premiums drive performance.
IBB vs XBI is a choice between large-cap commercial biotech stability and small-cap pipeline biotech volatility — IBB is appropriate for investors who want biotech exposure with lower binary risk, while XBI is for those who want maximum sensitivity to M&A, FDA cycles, and clinical trial breakthroughs.
XBI holds the edge across 3 of 5 key metrics in this comparison. XBI has delivered stronger 1-year price return (+35.48% vs +34.41% for IBB).
- prefer biotech exposure anchored in large-cap commercial companies with established revenue and earnings
- value lower volatility within the biotech sector and want to avoid binary small-cap trial-readout risk
- want broad biotech coverage (250+ holdings) in a single fund without small-cap concentration
- are comfortable with the largest holdings (Amgen, Gilead) dominating performance due to cap weighting
- prefer equal-weight exposure that meaningfully includes small and mid-cap biotech pipeline companies
- value high sensitivity to M&A activity where large pharma acquires small biotechs at large premiums
- want maximum biotech beta during favorable FDA approval cycles or biotech bull market conditions
- are comfortable with deep drawdowns (50%+) during risk-off periods when small-cap biotech is avoided
| Metric | IBB | XBI |
|---|---|---|
| ETF scorei | 27.4 | 27.5 |
| Latest closei | $213.79 | $152.05 |
| 1M returni | +4.14% | -1.54% |
| 3M returni | +15.00% | +3.22% |
| 6M returni | +25.66% | +14.01% |
| 1Y returni | +34.41% | +35.48% |
The ETF score weights long-term returns and risk-adjusted performance most heavily, but still rewards low expense ratios, larger fund size, and broader diversification — so it can favor low-cost, broad, mega-cap funds over smaller thematic or actively-managed funds even when the latter have delivered stronger returns.
How much would $10,000 be worth today if invested at the start of each period, with all dividends reinvested?
| Period | IBB | XBI |
|---|---|---|
| 1Y ago | $13.63K (+36.3%) started 2025-11-03 | $13.96K (+39.6%) started 2025-11-03 |
| 5Y ago | $13.31K (+33.1%) started 2021-11-03 | $11.48K (+14.8%) started 2021-11-03 |
| 10Y ago | $27.35K (+173.5%) started 2016-11-03 | $29.33K (+193.3%) started 2016-11-03 |
Hypothetical — past performance does not guarantee future results.
| Metric | IBB | XBI |
|---|---|---|
| Expense ratioi | 0.44% | 0.35% |
| Total assets (AUM)i | $11.2B | $10.36B |
| Dividend yieldi | 0.16% | 0.35% |
| Trailing P/Ei | 26.71 | N/A |
| Betai | 0.72 | 0.86 |
| 52-week change | 34.41% | 35.48% |
| Metric | IBB | XBI |
|---|---|---|
| 1Y returni | +34.41% | +35.48% |
| 6M returni | +25.66% | +14.01% |
| 3M returni | +15.00% | +3.22% |
| 1M returni | +4.14% | -1.54% |
| 1Y Sharpe ratio | 1.28 | 1.13 |
| Betai | 0.72 | 0.86 |
| Dividend yieldi | 0.16% | 0.35% |
| 5Y CAGR | +5.62% | +2.67% |
Over the past year, IBB and XBI have moved strongly in the same direction (correlation of 0.92), based on daily returns.
Lower drawdown and smaller single-period drops generally indicate a smoother ride, though they do not guarantee lower future risk.
| Period | Metric | IBB | XBI |
|---|---|---|---|
| 1Y | Growthi | +36.05% | +39.00% |
| CAGRi | +36.19% | +39.15% | |
| Volatilityi | 22.82% | 29.11% | |
| Sharpe ratioi | 1.28 | 1.13 | |
| Sortino ratioi | 2.01 | 1.73 | |
| Max drawdowni | 9.63% | 14.88% | |
| Current drawdowni | 1.87% | 10.32% | |
| Avg drawdowni | 3.14% | 4.21% | |
| Ulcer Indexi | 3.86% | 5.41% | |
| Max daily dropi | 3.01% | 4.39% | |
| Max wkly dropi | 5.22% | 7.48% | |
| 5Y | Growthi | +31.39% | +14.06% |
| CAGRi | +5.62% | +2.67% | |
| Volatilityi | 22.42% | 32.51% | |
| Sharpe ratioi | 0.16 | 0.11 | |
| Sortino ratioi | 0.22 | 0.15 | |
| Max drawdowni | 35.69% | 53.18% | |
| Current drawdowni | 1.87% | 10.32% | |
| Avg drawdowni | 16.06% | 28.87% | |
| Ulcer Indexi | 18.16% | 31.88% | |
| Max daily dropi | 5.77% | 8.21% | |
| Max wkly dropi | 12.64% | 20.07% | |
| 10Y | Growthi | +166.51% | +189.21% |
| CAGRi | +10.30% | +11.21% | |
| Volatilityi | 23.22% | 31.95% | |
| Sharpe ratioi | 0.35 | 0.35 | |
| Sortino ratioi | 0.50 | 0.51 | |
| Max drawdowni | 39.82% | 63.89% | |
| Current drawdowni | 1.87% | 12.03% | |
| Avg drawdowni | 13.56% | 27.19% | |
| Ulcer Indexi | 17.06% | 33.80% | |
| Max daily dropi | 8.96% | 12.35% | |
| Max wkly dropi | 18.45% | 23.56% |
| Category | IBB | XBI |
|---|---|---|
| Fund name | iShares Biotechnology ETF | State Street SPDR S&P Biotech ETF |
| Type | ETF | ETF |
| Expense ratioi | 0.44% | 0.35% |
| Total assets (AUM)i | $11.2B | $10.36B |
| Dividend yieldi | 0.16% | 0.35% |
- Market-cap weighting means largest holdings are commercially established companies with real revenue and cash flows
- Broad coverage of 250+ biotechs provides exposure to the full value chain from small-cap pipeline to large-cap commercial
- Lower volatility than XBI due to large-cap anchor positions like Amgen and Gilead that have dividend-paying revenue bases
- Equal-weight methodology gives meaningful exposure to small and mid-cap biotechs that drive the most volatile and potentially highest-return biotech stories
- High sensitivity to M&A premiums: when large pharma acquires small biotech targets at 50–100% premiums, XBI benefits more than IBB
- Rebalancing mechanism automatically trims winners and adds to laggards, providing a built-in buy-low-sell-high rebalancing effect
- Heavy concentration in a few large-cap names means IBB behaves less like a biotech sector ETF and more like a handful of large pharma-biotech hybrids
- Breakthrough small-cap biotech stories have less impact on IBB's performance than on XBI due to weighting methodology
- 0.45% expense ratio is higher than many equity ETFs
- Very high volatility — XBI can decline 50%+ in bear market conditions as small-cap biotech investors flee risk
- Binary clinical trial results for small-cap holdings can drive significant single-day drawdowns in the ETF
- Equal-weight rebalancing can hurt returns in strong bull markets by trimming winning positions too early
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