As of September 29, 2026, the three largest insider holders of MGTX are Advisors Llc Perceptive (Director, 10.23Mn shares), Alexandria Forbes (President Ceo, 1.33Mn shares), Richard Giroux (Cfo Coo, 908.53K shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Advisors Llc Perceptive | Director, TenPercentOwner | 0 | 10,231,103 | 10,231,103 | 75.4% | 02 Jan, 2026 |
| 2 | Alexandria Forbes | President Ceo | 1,325,695 | 0 | 1,325,695 | 9.8% | 18 Aug, 2026 |
| 3 | Richard Giroux | Cfo Coo | 908,530 | 0 | 908,530 | 6.7% | 21 Jul, 2026 |
| 4 | Stuart Naylor | Chief Sci Ofcr, Ophthalmology | 640,846 | 0 | 640,846 | 4.7% | 07 Jul, 2026 |
| 5 | Keith R. Harris | Director | 200,000 | 0 | 200,000 | 1.5% | 10 Jun, 2026 |
| 6 | Robert K Zeldin | Chief Medical Officer | 172,888 | 0 | 172,888 | 1.3% | 23 Feb, 2026 |
| 7 | Robert J Wollin | General Counsel And Secretary | 57,377 | 0 | 57,377 | 0.4% | 23 Feb, 2026 |
| 8 | Martin Indyk | Director | 35,000 | 0 | 35,000 | 0.3% | 06 Jun, 2024 |
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 |
|---|---|---|---|---|---|---|---|---|
| 23 Sep, 2026 | Alan Sebulsky | Director | Acquired A | 100,000 | $0.00 | $0 | 100,000 | Direct |
| 18 Aug, 2026 | Alexandria Forbes | President Ceo | Disposed S | 62,000 | $13.86 | $859.32K | 1,325,695 | Direct |
| 21 Jul, 2026 | Richard Giroux | Cfo Coo | Disposed S | 56,000 | $12.51 | $700.56K | 908,530 | Direct |
| 07 Jul, 2026 | Stuart Naylor | Chief Sci Ofcr, Ophthalmology | Disposed S | 2,547 | $13.86 | $35.30K | 665,958 | Direct |
| 07 Jul, 2026 | Stuart Naylor | Chief Sci Ofcr, Ophthalmology | Disposed S | 25,112 | $14.90 | $374.17K | 640,846 | Direct |
| 25 Jun, 2026 | Stuart Naylor | Chief Sci Ofcr, Ophthalmology | Acquired A | 70,000 | $0.00 | $0 | 70,000 | Direct |
| 25 Jun, 2026 | Richard Giroux | Cfo Coo | Acquired A | 980,000 | $0.00 | $0 | 980,000 | Direct |
| 25 Jun, 2026 | Alexandria Forbes | President Ceo | Acquired A | 980,000 | $0.00 | $0 | 980,000 | Direct |
| 25 Jun, 2026 | Robert J Wollin | General Counsel And Secretary | Acquired A | 100,000 | $0.00 | $0 | 100,000 | Direct |
| 25 Jun, 2026 | Robert K Zeldin | Chief Medical Officer | Acquired A | 100,000 | $0.00 | $0 | 100,000 | Direct |
| 11 Jun, 2026 | Nicole Seligman | Director | Acquired A | 60,000 | $0.00 | $0 | 60,000 | Direct |
| 11 Jun, 2026 | Thomas E Shenk | Director | Acquired A | 69,662 | $0.00 | $0 | 69,662 | Direct |
| 11 Jun, 2026 | Debra Yu | Director | Acquired A | 60,000 | $0.00 | $0 | 60,000 | Direct |
| 11 Jun, 2026 | Ellen Hukkelhoven | Director | Acquired A | 60,000 | $0.00 | $0 | 60,000 | Direct |
| 11 Jun, 2026 | Advisors Llc Perceptive | Director, TenPercentOwner | Acquired A | 60,000 | $0.00 | $0 | 60,000 | Indirect |
| 11 Jun, 2026 | Neil Mendoza | Director | Acquired A | 66,641 | $0.00 | $0 | 66,641 | Direct |
| 11 Jun, 2026 | Keith R. Harris | Director | Acquired A | 106,441 | $0.00 | $0 | 106,441 | Direct |
| 10 Jun, 2026 | Keith R. Harris | Director | Acquired M | 75,000 | — | — | 200,000 | Direct |
| 10 Jun, 2026 | Keith R. Harris | Director | Disposed M | 75,000 | $0.00 | $0 | 0 | Direct |
| 27 May, 2026 | Richard Giroux | Cfo Coo | Disposed G | 7,000 | $0.00 | $0 | 964,530 | Direct |