Arrowhead Pharmaceuticals's three largest insider shareholders as of September 29, 2026 are Christopher Richard Anzalone (Chief Executive Officer, 3.79Mn shares), Patrick O'Brien (Coo, 547.41K shares), Kenneth Allen Myszkowski (Chief Financial Officer, 455.43K shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Christopher Richard Anzalone | Chief Executive Officer | 3,792,739 | 0 | 3,792,739 | 61.4% | 05 Jan, 2026 |
| 2 | Patrick O'Brien | Coo | 547,408 | 0 | 547,408 | 8.9% | 08 Jan, 2026 |
| 3 | Kenneth Allen Myszkowski | Chief Financial Officer | 455,433 | 0 | 455,433 | 7.4% | 07 Jan, 2025 |
| 4 | Martin Javier San | Chief Medical Officer | 289,997 | 0 | 289,997 | 4.7% | 05 Jan, 2024 |
| 5 | James C Hamilton | Chief Medical Officer | 226,958 | 0 | 226,958 | 3.7% | 24 Apr, 2026 |
| 6 | Daniel Joseph Apel | Chief Financial Officer | 162,905 | 0 | 162,905 | 2.6% | 24 Apr, 2026 |
| 7 | Tracie Oliver | Chief Commercial Officer | 127,107 | 0 | 127,107 | 2.1% | 03 Jul, 2024 |
| 8 | Douglas B Given | Director | 124,167 | 0 | 124,167 | 2.0% | 18 Dec, 2024 |
| 9 | Michael S Perry | Director | 111,459 | 0 | 111,459 | 1.8% | 20 Aug, 2026 |
| 10 | Mauro Ferrari | Director | 69,053 | 0 | 69,053 | 1.1% | 30 Dec, 2025 |
| 11 | William D. Waddill | Director | 56,563 | 0 | 56,563 | 0.9% | 23 Dec, 2025 |
| 12 | Hongbo Lu | Director | 52,012 | 0 | 52,012 | 0.8% | 14 May, 2026 |
| 13 | Douglas S Ingram | Director | 46,215 | 0 | 46,215 | 0.7% | 18 Dec, 2025 |
| 14 | Victoria Vakiener | Director | 35,723 | 0 | 35,723 | 0.6% | 23 Dec, 2025 |
| 15 | Adeoye Y Olukotun | Director | 31,600 | 0 | 31,600 | 0.5% | 20 Aug, 2026 |
| 16 | Backer Marianne De | Director | 31,267 | 0 | 31,267 | 0.5% | 11 Jan, 2023 |
| 17 | Matthew Gregory Cohen | Director | 11,882 | 0 | 11,882 | 0.2% | 17 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 |
|---|---|---|---|---|---|---|---|---|
| 18 Aug, 2026 | Adeoye Y Olukotun | Director | Disposed S | 2,000 | $86.96 | $173.92K | 31,600 | Direct |
| 18 Aug, 2026 | Michael S Perry | Director | Disposed S | 11,600 | $87.30 | $1.01Mn | 111,459 | Direct |
| 15 Jun, 2026 | Matthew Gregory Cohen | Director | Acquired A | 11,882 | $0.00 | $0 | 11,882 | Direct |
| 12 May, 2026 | Hongbo Lu | Director | Disposed S | 2,970 | $76.88 | $228.33K | 52,012 | Direct |
| 22 Apr, 2026 | Daniel Joseph Apel | Chief Financial Officer | Disposed S | 3,208 | $70.11 | $224.91K | 172,792 | Direct |
| 23 Apr, 2026 | James C Hamilton | Chief Medical Officer | Disposed S | 10,000 | $75.00 | $750.00K | 226,958 | Direct |
| 22 Apr, 2026 | Daniel Joseph Apel | Chief Financial Officer | Disposed S | 1,157 | $70.45 | $81.51K | 171,635 | Direct |
| 22 Apr, 2026 | Daniel Joseph Apel | Chief Financial Officer | Disposed S | 8,730 | $71.92 | $627.86K | 162,905 | Direct |
| 05 Mar, 2026 | James C Hamilton | Chief Medical Officer | Disposed S | 10,000 | $64.19 | $641.90K | 236,958 | Direct |
| 06 Jan, 2026 | Daniel Joseph Apel | Chief Financial Officer | Acquired A | 75,000 | $0.00 | $0 | 176,200 | Direct |
| 06 Jan, 2026 | James C Hamilton | Chief Medical Officer | Acquired A | 75,000 | $0.00 | $0 | 246,958 | Direct |
| 06 Jan, 2026 | Patrick O'Brien | Coo | Disposed G | 540 | $0.00 | $0 | 474,368 | Direct |
| 06 Jan, 2026 | Patrick O'Brien | Coo | Disposed G | 540 | $0.00 | $0 | 473,828 | Direct |
| 06 Jan, 2026 | Patrick O'Brien | Coo | Disposed G | 540 | $0.00 | $0 | 473,288 | Direct |
| 06 Jan, 2026 | Patrick O'Brien | Coo | Disposed G | 440 | $0.00 | $0 | 472,848 | Direct |
| 06 Jan, 2026 | Patrick O'Brien | Coo | Disposed G | 440 | $0.00 | $0 | 472,408 | Direct |
| 06 Jan, 2026 | Patrick O'Brien | Coo | Acquired A | 75,000 | $0.00 | $0 | 547,408 | Direct |
| 31 Dec, 2025 | Patrick O'Brien | Coo | Disposed G | 560 | $0.00 | $0 | 526,641 | Direct |
| 02 Jan, 2026 | Christopher Richard Anzalone | Chief Executive Officer | Disposed S | 7,416 | $65.88 | $488.57K | 3,798,510 | Direct |
| 05 Jan, 2026 | James C Hamilton | Chief Medical Officer | Disposed S | 4,625 | $61.24 | $283.24K | 207,497 | Direct |