IBB vs XBI Stock Comparison: 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 (+70.87% vs +38.41% 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 score | 48.0 | 61.0 |
| Latest close | $173.64 | $140.72 |
| 1M return | +5.77% | +10.99% |
| 6M return | +3.74% | +16.74% |
| 1Y return | +38.41% | +70.87% |
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 | $13.88K (+38.8%) started 2025-06-18 | $17.15K (+71.5%) started 2025-06-18 |
| 5Y ago | $11.23K (+12.3%) started 2021-06-18 | $10.65K (+6.5%) started 2021-06-18 |
| 10Y ago | $21.23K (+112.3%) started 2016-06-20 | $26.69K (+166.9%) started 2016-06-20 |
Hypothetical — past performance does not guarantee future results.
| Metric | IBB | XBI |
|---|---|---|
| Expense ratio | 0.44% | 0.35% |
| Total assets (AUM) | $7.94B | $8.39B |
| Dividend yield | 0.23% | 0.32% |
| Trailing P/E | 22.48 | N/A |
| Beta | 0.72 | 0.85 |
| 52-week change | 38.41% | 70.87% |
| Metric | IBB | XBI |
|---|---|---|
| 1Y return | +38.41% | +70.87% |
| 6M return | +3.74% | +16.74% |
| 1M return | +5.77% | +10.99% |
| 1Y Sharpe ratio | 1.49 | 2.01 |
| Beta | 0.72 | 0.85 |
| Dividend yield | 0.23% | 0.32% |
| 5Y CAGR | +2.08% | +1.16% |
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 | Growth | +38.41% | +70.87% |
| CAGR | +38.44% | +70.93% | |
| Sharpe ratio | 1.49 | 2.01 | |
| Max drawdown | 9.63% | 9.72% | |
| Max daily drop | 3.01% | 4.39% | |
| Max wkly drop | 5.15% | 6.12% | |
| 5Y | Growth | +10.82% | +5.91% |
| CAGR | +2.08% | +1.16% | |
| Sharpe ratio | -0.00 | 0.06 | |
| Max drawdown | 39.82% | 54.71% | |
| Max daily drop | 5.77% | 8.21% | |
| Max wkly drop | 12.64% | 20.07% | |
| 10Y | Growth | +106.74% | +163.33% |
| CAGR | +7.54% | +10.17% | |
| Sharpe ratio | 0.24 | 0.32 | |
| Max drawdown | 39.82% | 63.89% | |
| Max daily drop | 8.96% | 12.35% | |
| Max wkly drop | 18.45% | 23.56% |
| Category | IBB | XBI |
|---|---|---|
| Fund name | iShares Biotechnology ETF | State Street SPDR S&P Biotech ETF |
| Type | ETF | ETF |
| Expense ratio | 0.44% | 0.35% |
| Total assets (AUM) | $7.94B | $8.39B |
| Dividend yield | 0.23% | 0.32% |
- →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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