998 + Investors. Track Smart Money conviction in BIIB. See who's accumulating, reducing, or initiating positions.
Based on 1007 hedge funds · latest filing: 2026 Q1 · updated quarterly
Methodology note: these Smart Money cards use consecutive 13F disclosure snapshots, not trade-by-trade execution data. "Buying", "selling", "new holders", and "trimmed" refer to quarter-over-quarter changes in reported holders, aggregate shares, or disclosed position values between filings. They are useful for ownership regime analysis and crowding, but they do not imply exact trade timing on the filing date.
In 2026 Q1, 554 hedge funds were net buyers of BIIB (146 opened a new position, 408 added to an existing one), while 425 reduced or exited (295 trimmed, 130 sold completely) — a 57% buyer ratio, indicating a slight buying edge. This marks 3 consecutive quarters of net institutional buying — a persistent conviction signal. 55% of total institutional value in BIIB is held by top-100 AUM funds, reflecting elite-tier ownership quality. Net fund flow last quarter: +16 funds (more new holders than closures). Total institutional holders: 1007.
Institutional ownership data sourced from SEC EDGAR Form 13F-HR filings.
Signal Freshness measures how much BIIB has moved relative to its sector benchmark (XLV) since the 2026 Q1 13F filing. A stock that has barely outrun its sector is still a relatively fresh entry point — the fund's thesis has not yet been priced in by the broader market.
BIIB outperformed XLV by nan% since March 31, 2026.
Since the filing became public, BIIB outperformed XLV by nan% .
Interpretation: The stock is tracking its sector benchmark closely. The signal remains fresh and the entry point is still near the fund's implied reference. Learn more →
Many quality funds hold this stock, but top-tier positions remain relatively small.
Track Smart Money conviction in BIIB. See who's accumulating, reducing, or initiating positions.
| Metric | All 13F Filers (2026 Q1) | Prior (2025 Q4) | Change |
|---|---|---|---|
| Funds Holding | 998 | 991 | 0.71% |
| 13F Shares | 134M | 144M | -6.82% |
| Total Value | $23.66B | $25.14B | -5.92% |
| New Positions | 142 | 194 | -52 |
| Increased Positions | 387 | 312 | +75 |
| Closed Positions | 135 | 96 | +39 |
| Reduced Positions | 292 | 299 | -7 |
| Total Calls | 22 | 26 | -15.38% |
| Total Puts | 24 | 26 | -7.69% |
| PUT/CALL Ratio | 1.09 | 1.0 | Neutral |
| Market Cap | -- |
| Enterprise Value | -- |
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| PEG Ratio (5yr expected) | -- |
| Price/Sales (ttm) | -- |
| Price/Book (mrq) | -- |
| Enterprise Value/Revenue | -- |
| Enterprise Value/EBITDA | -- |
| Beta (5Y Monthly) | -- |
| Short Ratio (Days to Cover) | -- |
| Short % of Float | -- |
| Profit Margin | -- |
| Return on Assets (ttm) | -- |
| Return on Equity (ttm) | -- |
| Revenue (ttm) | -- |
| Net Income Avi to Common (ttm) | -- |
| Diluted EPS (ttm) | -- |
| Total Cash (mrq) | -- |
| Total Debt/Equity (mrq) | -- |
| Levered Free Cash Flow (ttm) | -- |
Explore institutional interest and hedge fund ownership dynamics. Analyze portfolio weights, new positions, and conviction trends in BIIB. Verified SEC 13F-HR filings.
| Investor | Ownership History |
% of Portfolio | Prev % | Rank | Conviction | Avg Buy Price | 13F Score™ 3Y / 7Y | Sell Timing | Shares | Mkt Value | Change | Change % | Source | Quarter | Filed |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Buying streak — 3 quarters in a row: For 3 consecutive quarters, more hedge funds added BIIB than sold it. That's a consistent pattern of professional buying — not a one-time trade. When institutions keep buying quarter after quarter, it usually means they see a multi-year opportunity, not just a short-term momentum flip.
Slight buying edge — 57% buying: Last quarter: 554 funds bought or added vs 425 that reduced or exited. It's nearly a 50/50 split — some institutions are convinced, others are taking profits. This mixed picture is normal near price highs.
Elite ownership — 55% AUM from top-100 funds: 64 of 1001 holders are among the 100 largest funds by AUM, controlling 55% of total institutional value in BIIB. When the biggest players dominate the cap table, it signifies deep institutional support — since mega-funds deploy the most rigorous due diligence and capital.
66% of holders stayed for 2+ years: 662 out of 1,007 hedge funds have held BIIB for over 2 years without selling. Long-term investors are generally harder to shake out during market stress, creating a stable ownership base that limits the risk of sudden capitulation.
As of today, BIIB has moved nan% since the 2026 Q1 13F filing date (May 15, 2026), compared to +3.0% for the XLV sector ETF — an outperformance of nan%. Since the quarter end (March 31, 2026), BIIB has gained nan% vs +1.9% for XLV. The stock is tracking its sector benchmark closely. The signal remains fresh and the entry point is still near the fund's implied reference.
All holdings data is sourced from SEC Form 13F filings, which institutional investment managers with over $100 million in assets are required to submit quarterly. Data is parsed directly from SEC EDGAR.
Disclaimer: The information on this page is for informational purposes only and does not constitute investment advice, a recommendation, or an offer to buy or sell any security. Institutional holdings data is sourced from SEC Form 13F filings and reflects positions as of the filing date. Past performance of any fund or portfolio is not indicative of future results. 13Foresight is not a registered investment adviser. Always conduct your own due diligence before making investment decisions.