SION's three largest insider shareholders as of September 29, 2026 are Gp A, Llc Tpg (TenPercentOwner, 6.49Mn shares), Peter A. Thompson (Director, 3.70Mn shares), Venture Fund Xi, L.P. Atlas (TenPercentOwner, 3.69Mn shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Gp A, Llc Tpg | TenPercentOwner | 0 | 6,494,962 | 6,494,962 | 28.7% | 26 Jan, 2026 |
| 2 | Venture Fund Xi, L.P. Atlas | TenPercentOwner | 2,886,293 | 807,727 | 3,694,020 | 16.3% | 10 Feb, 2025 |
| 3 | Capital Management, L.P. Ra | Director, TenPercentOwner | 0 | 3,448,812 | 3,448,812 | 15.2% | 21 Sep, 2026 |
| 4 | Bruce Booth | Director | 0 | 2,995,602 | 2,995,602 | 13.2% | 21 Oct, 2025 |
| 5 | Advisors Llc Orbimed | Director | 0 | 2,469,959 | 2,469,959 | 10.9% | 09 Jul, 2026 |
| 6 | Peter A. Thompson | Director | 0 | 2,469,959 | 2,469,959 | 10.9% | 09 Jul, 2026 |
| 7 | Michael Cloonan | President Ceo | 765,393 | 0 | 765,393 | 3.4% | 18 Sep, 2026 |
| 8 | Elena Ridloff | Cfo And Cbo | 133,069 | 0 | 133,069 | 0.6% | 18 Sep, 2026 |
| 9 | Charlotte Mckee | Cmo And Head Of Rd | 128,415 | 0 | 128,415 | 0.6% | 18 Sep, 2026 |
| 10 | Jennifer Fitzpatrick | Clo And Head Of Program Mgmt. | 56,265 | 0 | 56,265 | 0.2% | 18 Sep, 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 |
|---|---|---|---|---|---|---|---|---|
| 17 Sep, 2026 | Capital Management, L.P. Ra | Director, TenPercentOwner | Disposed S | 3,415,011 | $6.32 | $21.58Mn | 3,482,612 | Indirect |
| 17 Sep, 2026 | Capital Management, L.P. Ra | Director, TenPercentOwner | Disposed S | 33,800 | $7.46 | $252.15K | 3,448,812 | Indirect |
| 17 Sep, 2026 | Elena Ridloff | Cfo And Cbo | Acquired A | 47,269 | $0.00 | $0 | 85,801 | Direct |
| 17 Sep, 2026 | Jennifer Fitzpatrick | Clo And Head Of Program Mgmt. | Acquired A | 28,133 | $0.00 | $0 | 28,133 | Direct |
| 17 Sep, 2026 | Michael Cloonan | President Ceo | Acquired A | 109,025 | $0.00 | $0 | 656,368 | Direct |
| 17 Sep, 2026 | Charlotte Mckee | Cmo And Head Of Rd | Acquired A | 50,000 | $0.00 | $0 | 78,415 | Direct |
| 17 Sep, 2026 | Michael Cloonan | President Ceo | Acquired A | 109,025 | $0.00 | $0 | 765,393 | Direct |
| 17 Sep, 2026 | Charlotte Mckee | Cmo And Head Of Rd | Acquired A | 50,000 | $0.00 | $0 | 128,415 | Direct |
| 17 Sep, 2026 | Jennifer Fitzpatrick | Clo And Head Of Program Mgmt. | Acquired A | 28,132 | $0.00 | $0 | 56,265 | Direct |
| 17 Sep, 2026 | Elena Ridloff | Cfo And Cbo | Acquired A | 47,268 | $0.00 | $0 | 133,069 | Direct |
| 17 Sep, 2026 | Charlotte Mckee | Cmo And Head Of Rd | Acquired A | 155,700 | $0.00 | $0 | 155,700 | Direct |
| 17 Sep, 2026 | Jennifer Fitzpatrick | Clo And Head Of Program Mgmt. | Acquired A | 103,140 | $0.00 | $0 | 103,140 | Direct |
| 17 Sep, 2026 | Elena Ridloff | Cfo And Cbo | Acquired A | 165,440 | $0.00 | $0 | 165,440 | Direct |
| 17 Sep, 2026 | Michael Cloonan | President Ceo | Acquired A | 436,100 | $0.00 | $0 | 436,100 | Direct |
| 17 Sep, 2026 | Charlotte Mckee | Cmo And Head Of Rd | Disposed D | 155,700 | $0.00 | $0 | 0 | Direct |
| 17 Sep, 2026 | Jennifer Fitzpatrick | Clo And Head Of Program Mgmt. | Disposed D | 103,140 | $0.00 | $0 | 0 | Direct |
| 17 Sep, 2026 | Michael Cloonan | President Ceo | Disposed D | 436,100 | $0.00 | $0 | 0 | Direct |
| 17 Sep, 2026 | Elena Ridloff | Cfo And Cbo | Disposed D | 165,440 | $0.00 | $0 | 0 | Direct |
| 07 Jul, 2026 | Peter A. Thompson | Director | Disposed S | 85,918 | $44.86 | $3.85Mn | 2,469,959 | Indirect |
| 07 Jul, 2026 | Advisors Llc Orbimed | Director | Disposed S | 85,918 | $44.86 | $3.85Mn | 2,469,959 | Indirect |