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Biological Products, (No Diagnostic Substances)
Computed from SEC EDGAR filings and closing prices — not copied from any wealth ranking. Dataset . How we calculate this.
Revenue and net income below are for fiscal period FY2025, the period label carried by this company’s own annual XBRL filings to the SEC. Fiscal years do not line up between companies — one company’s FY2026 can cover much the same months as another’s FY2025 — so compare the periods, not just the numbers.
Headcount comes from Yahoo Finance, not from a filing. The date beside it is the day we retrieved the figure — it is not the date the company counted its staff, and Yahoo does not publish that date. Unlike the SEC filings behind the other figures on this page, this one carries no open licence, so we publish the number and nothing else from that source.
Everyone below has filed at least one insider report against this company.
Value is that share count priced at the same closing price used everywhere else on this site. A row priced from only some of a person’s securities says so — we do not quietly present a partial sum as a complete one.
The role comes from the relationship boxes a person ticks on their own insider filings — officer, director, ten per cent owner — not from anything we infer. Somebody who is both an officer and a director appears once, in the combined group, so the row count still matches the figure at the top of this page. Where no filing states a role we say so instead of guessing one.
| Insider | Reported role | Shares | Value | Last action |
|---|---|---|---|---|
| Officers who also sit on the board 2 | ||||
| Arnon Rosenthal | CEO | 3,106,922 | $7.64M | S Open-market sale Sep 3, 2026 position reported |
| Sara Kenkare-Mitra | President | 501,652 | $1.23M | S Open-market sale Dec 3, 2025 position reported |
| Directors 2 | ||||
| David M Wehner | Board Member | 115,330 | $283.7K | A Grant or award Jun 12, 2024 position reported |
| Errol B. Desouza | Board Member | 69,950 | $172.1K | A Grant or award Jun 17, 2026 position reported |
The rest — awards, shares withheld to pay tax, option exercises, gifts and so on — follow from an employment contract or a transfer arranged off-market, not from a decision to buy or sell, so counting them would turn this into a pay table.
A price of 0.00 is a real reported figure on gifts (G) and share awards (A) — not a gap in our data.
| Date | Insider | Transaction | Shares | Price | Value | Filing |
|---|---|---|---|---|---|---|
| Sep 3, 2026 | Arnon Rosenthal | S Open-market sale | 72,606 | $2.66 | $193.1K | SEC filing ↗ |
| Aug 19, 2026 | Arnon Rosenthal | G Bona fide gift | 350,000 | $0.00 | $0 | SEC filing ↗ |
| Aug 19, 2026 | Arnon Rosenthal | G Bona fide gift | 1,050,000 | $0.00 | $0 | SEC filing ↗ |
| Jun 17, 2026 | Errol B. Desouza | A Grant or award | 28,700 | $0.00 | $0 | SEC filing ↗ |
| Jun 2, 2026 | Arnon Rosenthal | S Open-market sale | 87,216 | $1.97 | $171.8K | SEC filing ↗ |
| Mar 13, 2026 | Arnon Rosenthal | A Grant or award | 116,246 | $0.00 | $0 | SEC filing ↗ |
| Mar 2, 2026 | Arnon Rosenthal | S Open-market sale | 81,864 | $2.12 | $173.6K | SEC filing ↗ |
| Dec 3, 2025 | Sara Kenkare-Mitra | S Open-market sale | 41,687 | $1.12 | $46.7K | SEC filing ↗ |
| Dec 3, 2025 | Arnon Rosenthal | S Open-market sale | 104,347 | $1.12 | $116.9K | SEC filing ↗ |
| Nov 10, 2025 | Arnon Rosenthal | A Grant or award | 174,167 | $0.00 | $0 | SEC filing ↗ |
| Sep 2, 2025 | Sara Kenkare-Mitra | S Open-market sale | 23,638 | $2.50 | $59.1K | SEC filing ↗ |
| Sep 2, 2025 | Arnon Rosenthal | S Open-market sale | 51,562 | $2.50 | $128.9K | SEC filing ↗ |
| Jul 1, 2025 | Sara Kenkare-Mitra | A Grant or award | 54,725 | $0.00 | $0 | SEC filing ↗ |
| Jul 1, 2025 | Arnon Rosenthal | A Grant or award | 137,125 | $0.00 | $0 | SEC filing ↗ |
| Jun 11, 2025 | Errol B. Desouza | A Grant or award | 28,700 | $0.00 | $0 | SEC filing ↗ |
| Jun 2, 2025 | Sara Kenkare-Mitra | S Open-market sale | 23,890 | $1.34 | $32.0K | SEC filing ↗ |
| Jun 2, 2025 | Arnon Rosenthal | S Open-market sale | 52,087 | $1.34 | $69.8K | SEC filing ↗ |
| Mar 3, 2025 | Sara Kenkare-Mitra | S Open-market sale | 29,073 | $1.47 | $42.7K | SEC filing ↗ |
| Mar 3, 2025 | Arnon Rosenthal | S Open-market sale | 40,330 | $1.47 | $59.3K | SEC filing ↗ |
| Dec 2, 2024 | Sara Kenkare-Mitra | S Open-market sale | 26,500 | $2.52 | $66.8K | SEC filing ↗ |
| Dec 2, 2024 | Arnon Rosenthal | S Open-market sale | 52,172 | $2.52 | $131.5K | SEC filing ↗ |
| Oct 1, 2024 | Sara Kenkare-Mitra | A Grant or award | 300,000 | $0.00 | $0 | SEC filing ↗ |
| Oct 1, 2024 | Arnon Rosenthal | A Grant or award | 610,500 | $0.00 | $0 | SEC filing ↗ |
| Sep 3, 2024 | Sara Kenkare-Mitra | S Open-market sale | 13,926 | $4.88 | $68.0K | SEC filing ↗ |
| Sep 3, 2024 | Arnon Rosenthal | S Open-market sale | 26,499 | $4.88 | $129.3K | SEC filing ↗ |
From SEC Form 4 filings. Every row links to the filing it came from. How we calculate this.
The report an officer, director or large shareholder must file after trading their own company’s stock.
Funds, trusts and other companies file the same ownership forms that executives do. Everything below is taken from those filings, with the position exactly as the filing states it.
Do not add these figures together. 5 of the positions below were reported on filings shared by several filers at once.
On a joint filing every named filer is listed against the whole position, so the same block of stock appears under each name. Those rows are marked joint.
| Owner | Reported role | Shares | Filed |
|---|---|---|---|
| Polaris Venture Management Co. VI, L.L.C. | TenPercentOwner | 9,853,817 joint | |
| Polaris Venture Partners Founders' Fund VI, L.P. | TenPercentOwner | 9,853,817 joint | |
| Polaris Venture Partners VI (AIV-B), L.P. | TenPercentOwner | 9,853,817 joint | |
| Polaris Venture Partners VI (AIV), L.P. | TenPercentOwner | 9,853,817 joint | |
| Polaris Venture Partners VI, L.P. | TenPercentOwner | 9,853,817 joint |
See the full ownership map — every entity that files as an owner of a US public company.
Think a number here is wrong? Open the linked filing and compare — how to report it.
Every figure on this page comes from filings to the U.S. SEC via EDGAR. Nothing here is estimated, and nothing is taken from press coverage or company websites.
Share count: cover page of the latest filing (dei:EntityCommonStockSharesOutstanding), taken from
Alector, Inc.’s own filings and multiplied by our closing price.
Full method.
the share count the company itself prints on the cover of its most recent filing, as of the date it signed that filing.
We do not take a market cap from a data vendor, and we do not estimate one: the figure is a share count from Alector, Inc.’s own SEC filings multiplied by the closing price we hold for the same stock.