Alector, Inc.
ALEC- Exchange
- Nasdaq
- Industry
- Biological Products, (No Diagnostic Substances)
- SEC CIK
- 0001653087
In the last 90 days, Alector, Inc. insiders filed 0 open-market purchases and 3 sales; 140 institutions reported holding it in 13F filings for Q2 2026, worth $183.4M in total; no superinvestor holds it.
Holders of 5% or more of ALEC
Holders whose latest Schedule 13D or 13G filing reports 5% or more of Alector, Inc., largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| TCG Crossover GP II, LLC | 13G | 9.20%10.0M shares | New | Nov 14, 20251 filing | Nov 14, 2025 | SEC |
| Rosenthal Arnon | 13G/A | 7.40%8.21M shares | – | Feb 6, 20261 filing | Feb 6, 2026 | SEC |
| Polaris Venture Partners VI, L.P. | 13G/A | 6.50%7.10M shares | – | Nov 13, 20251 filing | Nov 13, 2025 | SEC |
| BlackRock, Inc. | 13G/A | 5.10%5.20M shares | −1.10 ppfrom 6.20% | Apr 17, 20252 filings | Oct 17, 2025 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
10 Schedule 13D and 13G filings on Alector, Inc., newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Mar 26, 20263:24 PM ET | Vanguard Group Inc | 13G/A | 0.00%0 shares | –Below 5% | Mar 13, 2026 | SEC |
| Feb 17, 20268:23 AM ET | RTW Investments, LPand 1 other | 13G/A | 0.00%0 shares | −6.90 ppfrom 6.90%Below 5% | Dec 31, 2025 | SEC |
| Feb 6, 20264:30 PM ET | Rosenthal Arnon | 13G/A | 7.40%8.21M shares | – | Dec 31, 2025 | SEC |
| Nov 14, 20254:18 PM ET | TCG Crossover GP II, LLCand 4 others | 13G | 9.20%10.0M shares | New | Oct 22, 2025 | SEC |
| Nov 14, 20258:18 AM ET | RTW Investments, LPand 1 other | 13G | 6.90%6.99M shares | New | Sep 30, 2025 | SEC |
| Nov 13, 20254:41 PM ET | Polaris Venture Partners VI, L.P.and 10 others | 13G/A | 6.50%7.10M shares | – | Sep 30, 2025 | SEC |
| Nov 7, 202511:13 AM ET | FMR LLCand 1 other | 13G/A | 3.60%3.60M shares | –Below 5% | Oct 31, 2025 | SEC |
| Oct 17, 20256:40 PM ET | BlackRock, Inc. | 13G/A | 5.10%5.20M shares | −1.10 ppfrom 6.20% | Sep 30, 2025 | SEC |
| Aug 14, 20255:54 PM ET | Ra Capital Management, L.P.and 3 others | 13G/A | 0.00%0 shares | –Below 5% | Jun 30, 2025 | SEC |
| Apr 17, 20259:35 AM ET | BlackRock, Inc. | 13G/A | 6.20%6.12M shares | – | Mar 31, 2025 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell Alector, Inc. shares.
No Form 144 notices for Alector, Inc. are on file.