ALECTOR INC ALEC
COM · Common Stock · CUSIP 014442107 · ISIN US0144421072
Company in San Francisco, United States
- SectorHealth care
- IndustryBiological Products, (No Diagnostic Substances)
- HeadquartersSouth San Francisco, CA
- Founded2013
- Websitealector.com
- FilingsSEC EDGAR
* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once ($249.0k this quarter). Holder counts are more reliable. Shares outstanding: 101.2m as of 2025-08-01, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $1.40. Options: 4 managers hold calls ($228.7k notional), 4 hold puts ($18.9k).
Trends to Q2 2025
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q3 2022 | 168 |
| Q4 2022 | 155 |
| Q1 2023 | 150 |
| Q2 2023 | 146 |
| Q3 2023 | 150 |
| Q4 2023 | 149 |
| Q1 2024 | 158 |
| Q2 2024 | 161 |
| Q3 2024 | 160 |
| Q4 2024 | 151 |
| Q1 2025 | 142 |
| Q2 2025 | 137 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| Q3 2023 | 79 | 56 |
| Q4 2023 | 63 | 65 |
| Q1 2024 | 88 | 52 |
| Q2 2024 | 80 | 68 |
| Q3 2024 | 64 | 69 |
| Q4 2024 | 67 | 77 |
| Q1 2025 | 65 | 58 |
| Q2 2025 | 63 | 60 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q3 2024 | $698.3k | $433.1k | 0.62 |
| Q4 2024 | $398.6k | $157.3k | 0.39 |
| Q1 2025 | $401.7k | $28.8k | 0.07 |
| Q2 2025 | $228.7k | $18.9k | 0.08 |
Biggest buyers
| PRICE T ROWE ASSOCIATES INC /MD/ | Added | +4.2m |
| Eversept Partners, LP | Added | +1.4m |
| ADAR1 Capital Management, LLC | Added | +1.3m |
| ACADIAN ASSET MANAGEMENT LLC | Added | +729.7k |
| ROYAL BANK OF CANADA | Added | +729.6k |
| FMR LLC | Added | +608.6k |
| CITADEL ADVISORS LLC | Added | +546.4k |
| TD Asset Management Inc | Added | +540.0k |
| Vestal Point Capital, LP | Added | +472.5k |
| MACKENZIE FINANCIAL CORP | New | +274.4k |
Biggest sellers
| RA CAPITAL MANAGEMENT, L.P. | Sold out | -9.7m |
| JPMORGAN CHASE & CO | Reduced | -1.4m |
| FRANKLIN RESOURCES INC | Sold out | -834.3k |
| Almitas Capital LLC | Sold out | -321.6k |
| BlackRock, Inc. | Reduced | -306.1k |
| JANE STREET GROUP, LLC | Reduced | -232.6k |
| DIADEMA PARTNERS LP | Reduced | -190.5k |
| BNP PARIBAS FINANCIAL MARKETS | Reduced | -145.7k |
| DEUTSCHE BANK AG\ | Reduced | -111.8k |
| SPHERA FUNDS MANAGEMENT LTD. | Sold out | -109.2k |
Biggest calls
| SIMPLEX TRADING, LLC | Reduced | $129.0k92.8k shares |
| GROUP ONE TRADING LLC | Reduced | $58.0k41.4k shares |
| CITADEL ADVISORS LLC | Reduced | $41.7k29.8k shares |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | Unchanged | $00 shares |
Biggest puts
| CITADEL ADVISORS LLC | Reduced | $18.8k13.4k shares |
| GROUP ONE TRADING LLC | Reduced | $140100 shares |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | Unchanged | $00 shares |
| SIMPLEX TRADING, LLC | Unchanged | $0200 shares |
Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.
Major shareholders (over 5%)
Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.
| Holder | Stake |
|---|---|
| TCG Crossover GP II, LLC 13G · passive investor new · filed 2025-11-14 | 9.2% |
| Deep Track Capital, LP 13G · passive investor new · filed 2026-10-23 | 8.6% |
| BIOTECHNOLOGY VALUE FUND L P 13G · passive investor new · filed 2026-09-18 | 8.4% |
| Rosenthal Arnon 13G · exempt (held before listing) filed 2026-02-06 | 7.4% |
| BlackRock, Inc. 13G · institution +0.5 pts · filed 2026-04-27 | 5.2% |
| RA CAPITAL MANAGEMENT, L.P. 13G · passive investor +5.1 pts · filed 2026-10-26 | 5.1% |
Fell to 5% or below in the last year: Polaris Venture Partners VI, L.P. (4.7%, 2026-05-14), VANGUARD GROUP INC (0.0%, 2026-03-26), RTW INVESTMENTS, LP (0.0%, 2026-02-17)
Insider purchases and sales in Q2 2025
Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.
Officers and directors buying vs selling
Number of people, by quarter (10% owners not included)
Numbers
| Quarter | Buying | Bought | Selling | Sold | Sold under a plan |
|---|---|---|---|---|---|
| Q3 2023 | 0 | — | 5 | $3.1m | — |
| Q4 2023 | 0 | — | 4 | $255.5k | — |
| Q1 2024 | 0 | — | 4 | $281.8k | — |
| Q2 2024 | 0 | — | 4 | $255.8k | — |
| Q3 2024 | 0 | — | 7 | $581.0k | $78.4k |
| Q4 2024 | 0 | — | 4 | $277.3k | — |
| Q1 2025 | 0 | — | 4 | $152.6k | — |
| Q2 2025 | 0 | — | 4 | $125.3k | $1.4k |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2025-06-20 | Yaffe Kristine Director | Sold plan | $1.4k1.0k shares |
| 2025-06-02 | Rosenthal Arnon Chief Executive Officer, director | Sold | $69.8k52.1k shares |
| 2025-06-02 | Kenkare-Mitra Sara President and Head of R&D | Sold | $32.0k23.9k shares |
| 2025-06-02 | GRASSO MARC Chief Financial Officer | Sold | $22.1k16.5k shares |
Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).
Holders, Q2 2025
| Manager | Shares | Change |
|---|---|---|
| FMR LLC 0.00% of their portfolio | 15.0m $21.0m | Added +608.6k |
| BlackRock, Inc. 0.00% of their portfolio | 8.0m $11.2m | Reduced -306.1k |
| VANGUARD GROUP INC 0.00% of their portfolio | 6.0m $8.4m | Reduced -65.3k |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 4.9m $6.8m | Added +4.2m |
| Merck & Co., Inc. 2.43% of their portfolio | 3.5m $5.0m | Unchanged |
| ACADIAN ASSET MANAGEMENT LLC 0.01% of their portfolio | 2.2m $3.0m | Added +729.7k |
| Eversept Partners, LP 0.28% of their portfolio | 2.0m $2.8m | Added +1.4m |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 2.0m $2.8m | Added +20.0k |
| ADAR1 Capital Management, LLC 0.39% of their portfolio | 1.7m $2.4m | Added +1.3m |
| STATE STREET CORP 0.00% of their portfolio | 1.7m $2.4m | Added +69.6k |
| JACOBS LEVY EQUITY MANAGEMENT, INC 0.01% of their portfolio | 1.3m $1.9m | Reduced -11.2k |
| Euclidean Capital LLC 0.60% of their portfolio | 1.3m $1.8m | Unchanged |
| RENAISSANCE TECHNOLOGIES LLC 0.00% of their portfolio | 1.3m $1.8m | Added +221.0k |
| DEERFIELD MANAGEMENT COMPANY, L.P. 0.03% of their portfolio | 1.1m $1.5m | Unchanged |
| 5AM Venture Management, LLC 0.54% of their portfolio | 995.8k $1.4m | Unchanged |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 989.7k $1.4m | Reduced -111.8k |
| Vestal Point Capital, LP 0.07% of their portfolio | 977.0k $1.4m | Added +472.5k |
| DAFNA Capital Management LLC 0.35% of their portfolio | 912.9k $1.3m | Unchanged |
| Ikarian Capital, LLC 0.42% of their portfolio | 900.0k $1.3m | Reduced -50.0k |
| Sio Capital Management, LLC 0.48% of their portfolio | 845.5k $1.2m | Added +8.4k |
| ROYAL BANK OF CANADA 0.00% of their portfolio | 734.4k $1.0m | Added +729.6k |
| NORTHERN TRUST CORP 0.00% of their portfolio | 658.2k $921.4k | Reduced -39.1k |
| TD Asset Management Inc 0.00% of their portfolio | 651.7k $912.4k | Added +540.0k |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 647.7k $906.7k | Added +22.9k |
| MORGAN STANLEY 0.00% of their portfolio | 606.6k $849.2k | Added +259.8k |
| CITADEL ADVISORS LLC 0.00% of their portfolio | 551.8k $772.5k | Added +546.4k |
| D. E. Shaw & Co., Inc. 0.00% of their portfolio | 534.2k $747.9k | Added +64.9k |
| PANAGORA ASSET MANAGEMENT INC 0.00% of their portfolio | 516.7k $723.4k | Added +150.1k |
| BOOTHBAY FUND MANAGEMENT, LLC 0.02% of their portfolio | 458.9k $642.4k | Added +184.5k |
| MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio | 410.8k $575.1k | Added +146.0k |
| AQR CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 406.6k $569.3k | Reduced -86.0k |
| DIMENSIONAL FUND ADVISORS LP 0.00% of their portfolio | 383.3k $536.9k | Reduced -106.0k |
| TWO SIGMA ADVISERS, LP 0.00% of their portfolio | 377.0k $527.8k | Reduced -15.9k |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 374.5k $524.3k | Added +62.3k |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 343.9k $481.5k | Added +5.9k |
| New Leaf Venture Partners, L.L.C. 0.90% of their portfolio | 339.6k $475.4k | Unchanged |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE 0.00% of their portfolio | 313.6k $439.0k | Added +189.7k |
| MACKENZIE FINANCIAL CORP 0.00% of their portfolio | 274.4k $384.2k | New |
| Bank of New York Mellon Corp 0.00% of their portfolio | 268.9k $376.4k | Added +19.4k |
| Walleye Capital LLC 0.00% of their portfolio | 266.2k $372.7k | Reduced -39.4k |
| DIADEMA PARTNERS LP 0.23% of their portfolio | 266.0k $372.4k | Reduced -190.5k |
| State of Wyoming 0.04% of their portfolio | 223.1k $312.3k | Added +26.3k |
| TWO SIGMA INVESTMENTS, LP 0.00% of their portfolio | 222.1k $311.0k | Added +7.7k |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.00% of their portfolio | 203.8k $285.3k | Reduced -49.3k |
| Alphabet Inc. 0.01% of their portfolio | 175.9k $246.2k | Unchanged |
| Invesco Ltd. 0.00% of their portfolio | 175.8k $246.1k | Added +27.2k |
| BARCLAYS PLC 0.00% of their portfolio | 169.8k $237.7k | Added +44.7k |
| MEDICI CAPITAL LLC 0.27% of their portfolio | 167.2k $234.1k | Unchanged |
| Nuveen, LLC 0.00% of their portfolio | 155.6k $217.9k | Added +17.4k |
| LOS ANGELES CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 151.9k $212.7k | Added +7.6k |
| GSA CAPITAL PARTNERS LLP 0.01% of their portfolio | 150.7k $211.0k | New |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 126.6k $177.2k | Added +9.9k |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 115.0k $161.0k | New |
| STRS OHIO 0.00% of their portfolio | 110.4k $154.6k | Added +7.8k |
| Russell Investments Group, Ltd. 0.00% of their portfolio | 100.4k $144.3k | Added +46.9k |
| DekaBank Deutsche Girozentrale 0.00% of their portfolio | 100.0k $148.0k | Unchanged |
| ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio | 92.9k $130.1k | Added +10.8k |
| XTX Topco Ltd 0.00% of their portfolio | 73.3k $102.7k | Added +40.8k |
| SUSQUEHANNA FUNDAMENTAL INVESTMENTS, LLC 0.00% of their portfolio | 70.8k $99.1k | Reduced -67.1k |
| Cannell & Spears LLC 0.00% of their portfolio | 61.5k $86.1k | Reduced -100 |
| Persistent Asset Partners Ltd 0.07% of their portfolio | 61.1k $85.5k | Reduced -43.8k |
| IEQ CAPITAL, LLC 0.00% of their portfolio | 59.0k $82.6k | Reduced -21.4k |
| Velan Capital Investment Management LP 0.08% of their portfolio | 55.0k $77.0k | Unchanged |
| BANK OF MONTREAL /CAN/ 0.00% of their portfolio | 52.4k $73.3k | New |
| Vanguard Personalized Indexing Management, LLC 0.00% of their portfolio | 52.1k $72.9k | Added +17.2k |
| HSBC HOLDINGS PLC 0.00% of their portfolio | 51.7k $73.9k | Reduced -6.4k |
| Utah Retirement Systems 0.00% of their portfolio | 51.4k $72.0k | Unchanged |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 50.6k $70.8k | Added +11.2k |
| CITIGROUP INC 0.00% of their portfolio | 49.5k $69.2k | Reduced -13.3k |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. 0.00% of their portfolio | 46.3k $64.8k | Reduced -28.4k |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 45.5k $63.7k | Reduced -1.4m |
| ALGERT GLOBAL LLC 0.00% of their portfolio | 44.5k $62.2k | Unchanged |
| UBS Group AG 0.00% of their portfolio | 41.9k $58.6k | Reduced -41.2k |
| TUDOR INVESTMENT CORP ET AL 0.00% of their portfolio | 40.8k $57.1k | Reduced -1 |
| INTECH INVESTMENT MANAGEMENT LLC 0.00% of their portfolio | 39.9k $55.9k | Reduced -20.8k |
| Vontobel Holding Ltd. 0.00% of their portfolio | 38.0k $53.2k | Added +8.0k |
| Jasper Ridge Partners, L.P. 0.00% of their portfolio | 30.6k $42.9k | Unchanged |
| CWM, LLC 0.00% of their portfolio | 25.9k $36.0k | Reduced -7.7k |
| Blackstone Inc. 0.00% of their portfolio | 25.7k $36.0k | Unchanged |
| STATE BOARD OF ADMINISTRATION OF FLORIDA RETIREMENT SYSTEM 0.00% of their portfolio | 25.6k $35.8k | Unchanged |
| Apollon Wealth Management, LLC 0.00% of their portfolio | 25.0k $35.0k | Unchanged |
| VOYA INVESTMENT MANAGEMENT LLC 0.00% of their portfolio | 24.6k $34.5k | Reduced -24.6k |
| JANE STREET GROUP, LLC 0.00% of their portfolio | 24.0k $33.5k | Reduced -232.6k |
| Cerity Partners LLC 0.00% of their portfolio | 23.7k $33.2k | Reduced -17.8k |
| Cubist Systematic Strategies, LLC 0.00% of their portfolio | 21.8k $30.5k | New |
| Graham Capital Management, L.P. 0.00% of their portfolio | 21.4k $29.9k | Reduced -19.7k |
| PRUDENTIAL FINANCIAL INC 0.00% of their portfolio | 21.3k $29.9k | New |
| China Universal Asset Management Co., Ltd. 0.00% of their portfolio | 20.1k $28.1k | Added +208 |
| ProShare Advisors LLC 0.00% of their portfolio | 20.1k $28.1k | Reduced -2.1k |
| FNY Investment Advisers, LLC 0.01% of their portfolio | 20.0k $28.0k | Added +10.0k |
| Erste Asset Management GmbH 0.00% of their portfolio | 19.0k $28.1k | Unchanged |
| Police & Firemen's Retirement System of New Jersey 0.00% of their portfolio | 17.0k $23.8k | Unchanged |
| SEI INVESTMENTS CO 0.00% of their portfolio | 16.9k $23.6k | Unchanged |
| DLK Investment Management, LLC 0.01% of their portfolio | 15.5k $21.7k | Added +4.0k |
| AMERIPRISE FINANCIAL INC 0.00% of their portfolio | 14.1k $19.8k | Added +3.4k |
| DIVERSIFIED TRUST CO 0.00% of their portfolio | 14.1k $19.7k | Unchanged |
| SHELL ASSET MANAGEMENT CO 0.00% of their portfolio | 13.9k $19.0k | Reduced -6.7k |
| Tower Research Capital LLC (TRC) 0.00% of their portfolio | 13.4k $18.8k | Reduced -9.3k |
| US BANCORP \DE\ 0.00% of their portfolio | 12.4k $17.4k | Reduced -1.2k |
| BNP PARIBAS FINANCIAL MARKETS 0.00% of their portfolio | 11.6k $16.3k | Reduced -145.7k |