Alector's three largest insider shareholders as of September 05, 2026 are Terrance Mcguire (Director, 10.85Mn shares), Terrance Mcguire (Director, 10.85Mn shares), Venture Management Co. Vi, L.L.C. Polaris (TenPercentOwner, 9.85Mn shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Terrance Mcguire | Director, TenPercentOwner | 0 | 10,853,817 | 10,853,817 | 37.3% | 13 Sep, 2023 |
| 2 | Venture Management Co. Vi, L.L.C. Polaris | TenPercentOwner | 0 | 9,853,817 | 9,853,817 | 33.8% | 31 May, 2024 |
| 3 | Tillman U. Gerngross | Director | 2,644,319 | 0 | 2,644,319 | 9.1% | 15 Jun, 2023 |
| 4 | Arnon Rosenthal | Chief Executive Officer | 2,294,600 | 0 | 2,294,600 | 7.9% | 04 Sep, 2026 |
| 5 | Robert King | Chief Development Officer | 550,871 | 0 | 550,871 | 1.9% | 04 Oct, 2022 |
| 6 | Sara Kenkare-Mitra | President And Head Of Rd | 501,652 | 0 | 501,652 | 1.7% | 03 Dec, 2025 |
| 7 | Neil Lindsay Berkley | Cfo Chief Business Officer | 350,649 | 0 | 350,649 | 1.2% | 04 Sep, 2026 |
| 8 | Gary Romano | Chief Medical Officer | 332,977 | 0 | 332,977 | 1.1% | 05 Mar, 2025 |
| 9 | Marc Grasso | Chief Financial Officer | 296,072 | 0 | 296,072 | 1.0% | 04 Jun, 2025 |
| 10 | Robert Paul | Chief Medical Officer | 234,319 | 0 | 234,319 | 0.8% | 11 Aug, 2021 |
| 11 | Richard H Scheller | Director | 134,899 | 0 | 134,899 | 0.5% | 17 Jun, 2026 |
| 12 | Louis J Jr Lavigne | Director | 128,109 | 0 | 128,109 | 0.4% | 17 Jun, 2026 |
| 13 | Kristine Yaffe | Director | 124,109 | 0 | 124,109 | 0.4% | 17 Jun, 2026 |
| 14 | Elizabeth A. Garofalo | Director | 118,650 | 0 | 118,650 | 0.4% | 17 Jun, 2026 |
| 15 | David M. Wehner | Director | 115,330 | 0 | 115,330 | 0.4% | 12 Jun, 2024 |
| 16 | Grace Wong-Sarad | Principal Accounting Officer | 106,015 | 0 | 106,015 | 0.4% | 04 Sep, 2026 |
| 17 | Paula Hammond | Director | 103,609 | 0 | 103,609 | 0.4% | 17 Jun, 2026 |
| 18 | Shehnaaz Suliman | President And Coo | 102,598 | 0 | 102,598 | 0.4% | 14 Dec, 2021 |
| 19 | Errol B Desouza | Director | 98,650 | 0 | 98,650 | 0.3% | 17 Jun, 2026 |
| 20 | Mark Altmeyer | Director | 98,650 | 0 | 98,650 | 0.3% | 17 Jun, 2026 |
| 21 | Calvin Yu | Vice President, Finance | 76,686 | 0 | 76,686 | 0.3% | 07 Jul, 2021 |
Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.
| Date | Insider | Position | Transaction | Shares | Price | Value | Shares Held After | Ownership |
|---|---|---|---|---|---|---|---|---|
| 02 Sep, 2026 | Grace Wong-Sarad | Principal Accounting Officer | Disposed S | 656 | $2.75 | $1.80K | 114,805 | Direct |
| 03 Sep, 2026 | Neil Lindsay Berkley | Cfo Chief Business Officer | Disposed S | 29,251 | $2.66 | $77.95K | 350,649 | Direct |
| 03 Sep, 2026 | Arnon Rosenthal | Chief Executive Officer | Disposed S | 72,606 | $2.66 | $193.47K | 2,294,600 | Direct |
| 03 Sep, 2026 | Grace Wong-Sarad | Principal Accounting Officer | Disposed S | 5,165 | $2.67 | $13.77K | 109,640 | Direct |
| 04 Sep, 2026 | Grace Wong-Sarad | Principal Accounting Officer | Disposed S | 3,625 | $2.51 | $9.09K | 106,015 | Direct |
| 19 Aug, 2026 | Arnon Rosenthal | Chief Executive Officer | Disposed G | 1,050,000 | $0.00 | $0 | 922,875 | Indirect |
| 19 Aug, 2026 | Arnon Rosenthal | Chief Executive Officer | Acquired G | 350,000 | $0.00 | $0 | 1,002,500 | Indirect |
| 19 Aug, 2026 | Arnon Rosenthal | Chief Executive Officer | Acquired G | 350,000 | $0.00 | $0 | 1,002,500 | Indirect |
| 19 Aug, 2026 | Arnon Rosenthal | Chief Executive Officer | Acquired G | 350,000 | $0.00 | $0 | 1,002,500 | Indirect |
| 17 Jun, 2026 | Richard H Scheller | Director | Acquired A | 28,700 | $0.00 | $0 | 134,899 | Direct |
| 17 Jun, 2026 | Errol B Desouza | Director | Acquired A | 28,700 | $0.00 | $0 | 98,650 | Direct |
| 17 Jun, 2026 | Elizabeth A. Garofalo | Director | Acquired A | 28,700 | $0.00 | $0 | 118,650 | Direct |
| 17 Jun, 2026 | Kristine Yaffe | Director | Acquired A | 28,700 | $0.00 | $0 | 124,109 | Direct |
| 17 Jun, 2026 | Mark Altmeyer | Director | Acquired A | 28,700 | $0.00 | $0 | 98,650 | Direct |
| 17 Jun, 2026 | Louis J Jr Lavigne | Director | Acquired A | 28,700 | $0.00 | $0 | 128,109 | Direct |
| 17 Jun, 2026 | Paula Hammond | Director | Acquired A | 28,700 | $0.00 | $0 | 103,609 | Direct |
| 17 Jun, 2026 | Kristine Yaffe | Director | Acquired A | 9,450 | $0.00 | $0 | 9,450 | Direct |
| 17 Jun, 2026 | Paula Hammond | Director | Acquired A | 9,450 | $0.00 | $0 | 9,450 | Direct |
| 17 Jun, 2026 | Richard H Scheller | Director | Acquired A | 9,450 | $0.00 | $0 | 9,450 | Direct |
| 17 Jun, 2026 | Errol B Desouza | Director | Acquired A | 9,450 | $0.00 | $0 | 9,450 | Direct |