Atlas Venture Associates X, LLC
CIK 1742765 · last filed 2026-02-09
Atlas Venture Associates X, LLC is a corporate insider who has filed 7 SEC Form 4 insider transactions across 4 companies since 2018. The most recent filing, for GBIO, was dated Feb 9, 2026. Across all open-market trades the lifetime net is −$113.2M, making them a net seller over the disclosed history. Current disclosed insider exposure totals $658.9M across reported positions.
"Disclosed insider exposure" sums this person's most-recently-reported share counts across each company they're an insider in, multiplied by the current underlying price. It is not net worth — it misses retail holdings, private investments, real estate, index funds, and any company where the person isn't an SEC-reporting insider. For informational purposes only.
$658.89M
4
7
-$113.15M
Holdings By Company
| Symbol | Role | Shares | Price | Disclosed Exposure | Lifetime OM Net | Filings | Latest Filed |
|---|---|---|---|---|---|---|---|
| Generation Bio Co. (GBIO) Delisted | 10%+ Owner | 0 | $5.34 | $0 | -$14.05M | 3 | 2026-02-09 |
| IRON | 10%+ Owner | 2,235,846 | $67.99 | $152.02M | -$76.18M | 2 | 2024-01-12 |
| KYMR | 10%+ Owner | 5,879,854 | $86.20 | $506.87M | -$22.93M | 1 | 2023-01-13 |
| Tectonic Therapeutic, Inc. (AVRO) Delisted | 10%+ Owner | 4,756,478 | $16.80 | $79.91M | $0 | 1 | 2018-06-25 |
Recent Filings
7 filings| Filed | Symbol | Action | Net Shares | Net $ | Link |
|---|---|---|---|---|---|
| 2026-02-09 | Generation Bio Co. (GBIO) Delisted | U | −4,967,676 | $0 | EDGAR |
| 2024-01-12 | IRON | Sell (S) | −300,000 | -$19.20M | EDGAR |
| 2023-09-18 | IRON | Sell (S) | −1,072,347 | -$56.98M | EDGAR |
| 2023-01-13 | KYMR | Sell (S) | −758,844 | -$22.93M | EDGAR |
| 2021-09-24 | Generation Bio Co. (GBIO) Delisted | Sell (S) | −539,992 | -$14.05M | EDGAR |
| 2020-06-18 | Generation Bio Co. (GBIO) Delisted | Conv (C) | +60,240,192 | $0 | EDGAR |
| 2018-06-25 | Tectonic Therapeutic, Inc. (AVRO) Delisted | Conv (C) | +14,269,434 | $0 | EDGAR |