As of September 09, 2026, the three largest insider holders of AMPH are Jack Y. Zhang (Ceo Chief Scientific Officer, 4.24Mn shares), Jack Y. Zhang (Ceo Chief Scientific Officer, 4.24Mn shares), Jack Y. Zhang (Ceo Chief Scientific Officer, 4.24Mn shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Jack Y. Zhang | Ceo Chief Scientific Officer | 2,990,052 | 1,245,125 | 4,235,177 | 66.7% | 17 Mar, 2026 |
| 2 | Mary Z. Luo | Coo,Chief Scientist Chairman | 1,104,416 | 0 | 1,104,416 | 17.4% | 11 Jan, 2024 |
| 3 | Rong Zhou | Senior Evp, Production Center | 344,197 | 0 | 344,197 | 5.4% | 03 Sep, 2026 |
| 4 | William J Peters | Cfo, Evp Treasurer | 172,846 | 0 | 172,846 | 2.7% | 11 Aug, 2026 |
| 5 | Howard Lee | Director | 159,350 | 0 | 159,350 | 2.5% | 03 Jun, 2026 |
| 6 | Yakob Liawatidewi | Evp Corp Admin Center | 121,892 | 0 | 121,892 | 1.9% | 17 Mar, 2026 |
| 7 | Floyd F. Petersen | Director | 71,368 | 0 | 71,368 | 1.1% | 15 Dec, 2025 |
| 8 | Michael A Zasloff | Director | 37,667 | 0 | 37,667 | 0.6% | 03 Jun, 2026 |
| 9 | Diane G. Gerst | Evp, Qa Regulatory Affairs | 31,899 | 0 | 31,899 | 0.5% | 03 Jun, 2026 |
| 10 | Richard K Prins | Director | 29,625 | 0 | 29,625 | 0.5% | 12 Aug, 2026 |
| 11 | Gayle Deflin | Director | 19,057 | 0 | 19,057 | 0.3% | 03 Jun, 2026 |
| 12 | David Russell Gaugh | Director | 14,447 | 0 | 14,447 | 0.2% | 03 Jun, 2026 |
| 13 | Anthony T Pierce | Director | 7,886 | 0 | 7,886 | 0.1% | 13 Jul, 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 Aug, 2026 | Richard K Prins | Director | Disposed S | 7,973 | $20.30 | $161.85K | 29,625 | Direct |
| 07 Aug, 2026 | William J Peters | Cfo, Evp Treasurer | Acquired M | 5,053 | $19.79 | $100.00K | 181,026 | Direct |
| 07 Aug, 2026 | William J Peters | Cfo, Evp Treasurer | Disposed S | 8,180 | $22.48 | $183.89K | 172,846 | Direct |
| 07 Aug, 2026 | William J Peters | Cfo, Evp Treasurer | Disposed M | 5,053 | $0.00 | $0 | 0 | Direct |
| 09 Jul, 2026 | Anthony T Pierce | Director | Acquired A | 7,886 | $0.00 | $0 | 7,886 | Direct |
| 09 Jul, 2026 | Anthony T Pierce | Director | Acquired A | 16,646 | $0.00 | $0 | 16,646 | Direct |
| 01 Jun, 2026 | Gayle Deflin | Director | Acquired A | 8,143 | $0.00 | $0 | 19,057 | Direct |
| 01 Jun, 2026 | Howard Lee | Director | Acquired A | 8,143 | $0.00 | $0 | 160,119 | Direct |
| 01 Jun, 2026 | Diane G. Gerst | Director | Acquired A | 8,143 | $0.00 | $0 | 31,899 | Direct |
| 01 Jun, 2026 | David Russell Gaugh | Director | Acquired A | 8,143 | $0.00 | $0 | 14,447 | Direct |
| 01 Jun, 2026 | Michael A Zasloff | Director | Acquired A | 8,143 | $0.00 | $0 | 37,667 | Direct |
| 01 Jun, 2026 | David Russell Gaugh | Director | Acquired A | 17,365 | $0.00 | $0 | 17,365 | Direct |
| 01 Jun, 2026 | Diane G. Gerst | Director | Acquired A | 17,365 | $0.00 | $0 | 17,365 | Direct |
| 02 Jun, 2026 | Howard Lee | Director | Disposed F | 769 | $18.45 | $14.19K | 159,350 | Direct |
| 01 Jun, 2026 | Gayle Deflin | Director | Acquired A | 17,365 | $0.00 | $0 | 17,365 | Direct |
| 01 Jun, 2026 | Michael A Zasloff | Director | Acquired A | 17,365 | $0.00 | $0 | 17,365 | Direct |
| 01 Jun, 2026 | Howard Lee | Director | Acquired A | 17,365 | $0.00 | $0 | 17,365 | Direct |
| 15 Mar, 2026 | Jack Y. Zhang | Ceo Chief Scientific Officer | Disposed F | 9,784 | $18.18 | $177.87K | 2,990,052 | Direct |
| 15 Mar, 2026 | Rong Zhou | Senior Evp, Production Center | Disposed F | 1,225 | $18.18 | $22.27K | 171,554 | Direct |
| 15 Mar, 2026 | William J Peters | Cfo, Evp Treasurer | Disposed F | 1,973 | $18.18 | $35.87K | 175,063 | Direct |