As of September 29, 2026, XBiotech's top three insider holders are John Simard (Chief Executive Officer, 3.87Mn shares), W Thorpe Mckenzie (Director, 2.60Mn shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | John Simard | Chief Executive Officer | 3,873,166 | 0 | 3,873,166 | 59.9% | 15 Oct, 2021 |
| 2 | W Thorpe Mckenzie | Director, TenPercentOwner | 2,597,471 | 0 | 2,597,471 | 40.1% | 13 Jan, 2022 |
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 |
|---|---|---|---|---|---|---|---|---|
| 01 Oct, 2025 | David Spencer Soffer | Director | Acquired A | 51,000 | $0.00 | $0 | 51,000 | Direct |
| 01 Oct, 2025 | Thomas Martin Kuendig | Director | Acquired A | 79,115 | $0.00 | $0 | 79,115 | Direct |
| 01 Oct, 2025 | Tevi David Troy | Director | Acquired A | 56,000 | $0.00 | $0 | 56,000 | Direct |
| 01 Oct, 2025 | Craig Evan Rademaker | Director | Acquired A | 92,104 | $0.00 | $0 | 92,104 | Direct |
| 17 Mar, 2025 | John Simard | Chief Executive Officer | Acquired A | 1,026,228 | $0.00 | $0 | 1,896,609 | Direct |
| 31 Jan, 2025 | John Simard | Chief Executive Officer | Disposed J | 2,470,355 | $10,000,000.00 | $24.70Tn | 870,381 | Direct |
| 20 Jun, 2024 | Jan-Paul Waldin | Director | Acquired A | 37,500 | $0.00 | $0 | 37,500 | Direct |
| 20 Jun, 2024 | W Thorpe Mckenzie | Director, TenPercentOwner | Acquired A | 37,500 | $0.00 | $0 | 37,500 | Direct |
| 20 Jun, 2024 | Donald H. Macadam | Director | Acquired A | 37,500 | $0.00 | $0 | 37,500 | Direct |
| 20 Jun, 2024 | Peter Libby | Director | Acquired A | 37,500 | $0.00 | $0 | 37,500 | Direct |
| 03 Jan, 2024 | John Simard | Chief Executive Officer | Acquired P | 2,470,355 | $10,000,000.00 | $24.70Tn | 3,840,736 | Direct |
| 23 Jun, 2023 | Donald H. Macadam | Director | Acquired A | 25,000 | $0.00 | $0 | 25,000 | Direct |
| 23 Jun, 2023 | Jan-Paul Waldin | Director | Acquired A | 25,000 | $0.00 | $0 | 25,000 | Direct |
| 23 Jun, 2023 | Peter Libby | Director | Acquired A | 25,000 | $0.00 | $0 | 25,000 | Direct |
| 23 Jun, 2023 | W Thorpe Mckenzie | Director, TenPercentOwner | Acquired A | 25,000 | $0.00 | $0 | 25,000 | Direct |
| 10 Feb, 2023 | Sushma Shivaswamy | Chief Scientific Officer | Acquired A | 100,000 | $0.00 | $0 | 100,000 | Direct |
| 22 Jun, 2022 | Peter Libby | Director | Acquired A | 25,000 | $0.00 | $0 | 25,000 | Direct |
| 22 Jun, 2022 | Donald H. Macadam | Director | Acquired A | 25,000 | $0.00 | $0 | 25,000 | Direct |
| 22 Jun, 2022 | Jan-Paul Waldin | Director | Acquired A | 25,000 | $0.00 | $0 | 25,000 | Direct |
| 22 Jun, 2022 | W Thorpe Mckenzie | Director, TenPercentOwner | Acquired A | 25,000 | $0.00 | $0 | 25,000 | Direct |