Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in ALEC held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | TCG Crossover Management, LLC | 10.0M | $21.5M | 0.0% | 9.007% | 0.62% |
| 2 | BlackRock, Inc. | 7.7M | $16.6M | +8.3% | 6.972% | 0.00% |
| 3 | Foresite Capital Management IV, LLC | 3.9M | $8.4M | 0.0% | 3.501% | 3.53% |
| 4 | VANGUARD CAPITAL MANAGEMENT LLC | 3.7M | $7.9M | — | 3.313% | 0.00% |
| 5 | Merck & Co., Inc. | 3.5M | $7.6M | 0.0% | 3.194% | 2.18% |
| 6 | D. E. Shaw & Co., Inc. | 3.3M | $7.2M | +40.9% | 3.002% | 0.01% |
| 7 | 683 Capital Management, LLC | 3.2M | $6.9M | -4.5% | 2.882% | 0.53% |
| 8 | BALYASNY ASSET MANAGEMENT LLC | 2.9M | $6.3M | -10.1% | 2.644% | 0.02% |
| 9 | Nantahala Capital Management, LLC | 2.8M | $6.1M | — | 2.536% | 0.31% |
| 10 | VANGUARD PORTFOLIO MANAGEMENT LLC | 2.6M | $5.6M | — | 2.327% | 0.00% |
| 11 | GEODE CAPITAL MANAGEMENT, LLC | 2.3M | $4.9M | +10.2% | 2.059% | 0.00% |
| 12 | JACOBS LEVY EQUITY MANAGEMENT, INC | 2.2M | $4.6M | -0.9% | 1.940% | 0.02% |
| 13 | Spruce Street Capital LP | 2.1M | $4.5M | +87.9% | 1.892% | 1.09% |
| 14 | Ikarian Capital, LLC | 2.1M | $4.5M | 0.0% | 1.876% | 0.48% |
| 15 | Kynam Capital Management, LP | 2.0M | $4.3M | 0.0% | 1.801% | 0.27% |
| 16 | MILLENNIUM MANAGEMENT LLC | 2.0M | $4.3M | +48.5% | 1.783% | 0.00% |
| 17 | STATE STREET CORP | 1.9M | $4.0M | +2.8% | 1.680% | 0.00% |
| 18 | FMR LLC | 1.8M | $3.9M | -19.5% | 1.618% | 0.00% |
| 19 | MEDICI CAPITAL LLC | 1.7M | $3.6M | +10.1% | 1.488% | 4.58% |
| 20 | Eversept Partners, LP | 1.4M | $2.9M | +34.3% | 1.217% | 0.19% |
| 21 | Euclidean Capital LLC | 1.3M | $2.8M | 0.0% | 1.178% | 0.72% |
| 22 | RENAISSANCE TECHNOLOGIES LLC | 1.3M | $2.8M | -16.6% | 1.160% | 0.00% |
| 23 | TWO SIGMA INVESTMENTS, LP | 1.3M | $2.8M | +23.1% | 1.152% | 0.00% |
| 24 | DEUTSCHE BANK AG\ | 1.1M | $2.3M | +5.6% | 0.984% | 0.00% |
| 25 | DEERFIELD MANAGEMENT COMPANY, L.P. (SERIES C) | 1.1M | $2.3M | 0.0% | 0.950% | 0.03% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). “% of Fund” shows how much of that investor’s total 13F portfolio is invested in ALEC — a direct measure of their conviction.
Filings activity in ALEC during Q1 2026, grouped by how each filer changed its position.
8 quarters of 13F filings · Δ columns show change vs prior quarter
| Quarter | Inst. Holders | Δ Holders | Ownership % | Δ Ownership | Total 13F Value | Δ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 134 | +3.9% | 106.84% | +32.62 pp | $181M | +44% |
| Q4 2025 | 129 | 12% | 74.22% | 48.18 pp | $126M | 39% |
| Q3 2025 | 147 | +8.1% | 122.40% | +70.50 pp | $208M | +136% |
| Q2 2025 | 136 | 2.9% | 51.90% | +0.84 pp | $88M | +1.7% |
| Q1 2025 | 140 | 6.0% | 51.06% | 28.11 pp | $87M | 36% |
| Q4 2024 | 149 | 6.3% | 79.17% | 114.24 pp | $134M | 59% |
| Q3 2024 | 159 | 0.6% | 193.41% | +1.03 pp | $329M | +0.5% |
| Q2 2024 | 160 | — | 192.38% | — | $327M | — |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Δ columns compare to the immediately prior filed quarter.
Quick answers to the most common questions about buying ALEC stock.
Based on Q1 2026 13F filings, institutional ownership of Alector, Inc. stands at 106.8%, held across 134 reporting institutions.
TCG Crossover Management, LLC is the largest reported institutional holder of ALEC, with approximately 10,000,000 shares worth $0.02B as of Q1 2026.
Yes — 3 widely-followed marquee investors appear among the top 25 institutional holders of ALEC, including MILLENNIUM MANAGEMENT LLC, RENAISSANCE TECHNOLOGIES LLC, TWO SIGMA INVESTMENTS, LP.
Our composite Smart Money Score for ALEC is 72 out of 100 (Bullish). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
30 institutions opened new positions in ALEC during Q1 2026, while 25 fully exited. 91 added to existing positions and 12 trimmed.
ALEC institutional ownership rose by 32.62 percentage points quarter-over-quarter, with a net change of +5 holders.
The top 10 institutions account for 51.8% of all reported 13F value in ALEC, and the top 25 account for 81.8%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.
Alector, Inc. (ALEC) Institutional Ownership