AC Immune's three largest insider shareholders as of August 29, 2026 are Andrea Pfeifer (Chief Executive Officer, 3.83Mn shares), Roy Ervin Twyman (Director, 92.56K shares), Monika Buetler (Director, 71.66K shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Andrea Pfeifer | Chief Executive Officer | 3,830,288 | 0 | 3,830,288 | 91.5% | 16 Apr, 2026 |
| 2 | Roy Ervin Twyman | Director | 92,556 | 0 | 92,556 | 2.2% | 15 Jun, 2026 |
| 3 | Monika Buetler | Director | 71,656 | 0 | 71,656 | 1.7% | 15 Jun, 2026 |
| 4 | Martin Zuegel | Interim Ceo | 71,408 | 0 | 71,408 | 1.7% | 15 Jun, 2026 |
| 5 | Carl Howard June | Director | 67,556 | 0 | 67,556 | 1.6% | 15 Jun, 2026 |
| 6 | Renee Aguiar-Lucander | Director | 51,136 | 0 | 51,136 | 1.2% | 15 Jun, 2026 |
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 |
|---|---|---|---|---|---|---|---|---|
| 11 Jun, 2026 | Roy Ervin Twyman | Director | Acquired A | 16,568 | $0.00 | $0 | 92,556 | Direct |
| 11 Jun, 2026 | Monika Buetler | Director | Acquired A | 17,751 | $0.00 | $0 | 71,656 | Direct |
| 11 Jun, 2026 | Martin Zuegel | Interim Ceo | Acquired A | 33,136 | $0.00 | $0 | 71,408 | Direct |
| 11 Jun, 2026 | Renee Aguiar-Lucander | Director | Acquired A | 16,568 | $0.00 | $0 | 51,136 | Direct |
| 11 Jun, 2026 | Carl Howard June | Director | Acquired A | 16,568 | $0.00 | $0 | 67,556 | Direct |
| 11 Jun, 2026 | Roy Ervin Twyman | Director | Acquired A | 38,889 | $0.00 | $0 | 38,889 | Direct |
| 11 Jun, 2026 | Martin Zuegel | Interim Ceo | Acquired A | 77,778 | $0.00 | $0 | 77,778 | Direct |
| 11 Jun, 2026 | Carl Howard June | Director | Acquired A | 38,889 | $0.00 | $0 | 38,889 | Direct |
| 11 Jun, 2026 | Renee Aguiar-Lucander | Director | Acquired A | 38,889 | $0.00 | $0 | 38,889 | Direct |
| 11 Jun, 2026 | Monika Buetler | Director | Acquired A | 41,667 | $0.00 | $0 | 41,667 | Direct |
| 15 Apr, 2026 | Andrea Pfeifer | Chief Executive Officer | Disposed S | 10,000 | $3.14 | $31.43K | 3,830,288 | Direct |
| 15 Apr, 2026 | Andrea Pfeifer | Chief Executive Officer | Disposed P | 10,000 | $3.14 | $31.43K | 3,830,288 | Direct |