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 4 of 5 key metrics in this comparison. XBI has delivered stronger 1-year price return (+69.54% vs +47.15% 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 | 75.0 | 82.0 |
| Latest closei | $207.07 | $158.25 |
| 1M returni | +1.73% | -1.16% |
| 6M returni | +25.93% | +29.49% |
| 1Y returni | +47.15% | +69.54% |
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 | $14.74K (+47.4%) started 2025-09-17 | $17.03K (+70.3%) started 2025-09-17 |
| 5Y ago | $12.25K (+22.5%) started 2021-09-17 | $12.06K (+20.6%) started 2021-09-17 |
| 10Y ago | $22.45K (+124.5%) started 2016-09-19 | $24.69K (+146.9%) started 2016-09-19 |
Hypothetical — past performance does not guarantee future results.
| Metric | IBB | XBI |
|---|---|---|
| Expense ratioi | 0.44% | 0.35% |
| Total assets (AUM)i | $10.47B | $11.4B |
| Dividend yieldi | 0.20% | 0.35% |
| Trailing P/Ei | 25.87 | N/A |
| Betai | 0.74 | 0.87 |
| 52-week change | 47.15% | 69.54% |
| Metric | IBB | XBI |
|---|---|---|
| 1Y returni | +47.15% | +69.54% |
| 6M returni | +25.93% | +29.49% |
| 1M returni | +1.73% | -1.16% |
| 1Y Sharpe ratio | 1.68 | 1.87 |
| Betai | 0.74 | 0.87 |
| Dividend yieldi | 0.20% | 0.35% |
| 5Y CAGR | +3.86% | +3.69% |
Over the past year, IBB and XBI have moved strongly in the same direction (correlation of 0.91), 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 | +47.15% | +69.54% |
| CAGRi | +47.19% | +69.60% | |
| Volatilityi | 21.82% | 28.02% | |
| Sharpe ratioi | 1.68 | 1.87 | |
| Sortino ratioi | 2.70 | 2.99 | |
| Max drawdowni | 9.63% | 10.51% | |
| Current drawdowni | 4.55% | 6.66% | |
| Avg drawdowni | 2.69% | 3.10% | |
| Ulcer Indexi | 3.51% | 4.15% | |
| Max daily dropi | 3.01% | 4.39% | |
| Max wkly dropi | 5.22% | 7.48% | |
| 5Y | Growthi | +20.87% | +19.85% |
| CAGRi | +3.86% | +3.69% | |
| Volatilityi | 22.30% | 32.39% | |
| Sharpe ratioi | 0.08 | 0.14 | |
| Sortino ratioi | 0.11 | 0.19 | |
| Max drawdowni | 39.02% | 53.18% | |
| Current drawdowni | 4.55% | 6.66% | |
| Avg drawdowni | 19.53% | 28.74% | |
| Ulcer Indexi | 21.71% | 31.84% | |
| Max daily dropi | 5.77% | 8.21% | |
| Max wkly dropi | 12.64% | 20.07% | |
| 10Y | Growthi | +118.66% | +143.54% |
| CAGRi | +8.14% | +9.32% | |
| Volatilityi | 23.21% | 31.93% | |
| Sharpe ratioi | 0.26 | 0.30 | |
| Sortino ratioi | 0.37 | 0.43 | |
| Max drawdowni | 39.82% | 63.89% | |
| Current drawdowni | 4.55% | 8.44% | |
| Avg drawdowni | 13.69% | 27.21% | |
| Ulcer Indexi | 17.11% | 33.81% | |
| 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 | $10.47B | $11.4B |
| Dividend yieldi | 0.20% | 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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