SION's three largest insider shareholders as of August 29, 2026 are Gp A, Llc Tpg (TenPercentOwner, 6.49Mn shares), Gp A, Llc Tpg (TenPercentOwner, 6.49Mn shares), Peter A. Thompson (Director, 3.70Mn shares).
| # | Insider | Position | Direct | Indirect | Total | Share of Insiders | Last Filed |
|---|---|---|---|---|---|---|---|
| 1 | Gp A, Llc Tpg | TenPercentOwner | 0 | 6,494,962 | 6,494,962 | 34.1% | 26 Jan, 2026 |
| 2 | Venture Fund Xi, L.P. Atlas | TenPercentOwner | 2,886,293 | 807,727 | 3,694,020 | 19.4% | 10 Feb, 2025 |
| 3 | Bruce Booth | Director | 0 | 2,995,602 | 2,995,602 | 15.7% | 21 Oct, 2025 |
| 4 | Advisors Llc Orbimed | Director | 0 | 2,671,721 | 2,671,721 | 14.0% | 29 May, 2026 |
| 5 | Peter A. Thompson | Director | 0 | 2,469,959 | 2,469,959 | 13.0% | 09 Jul, 2026 |
| 6 | Michael Cloonan | President Ceo | 547,343 | 0 | 547,343 | 2.9% | 22 Oct, 2025 |
| 7 | Capital Management, L.P. Ra | Director, TenPercentOwner | 0 | 159,033 | 159,033 | 0.8% | 24 Nov, 2025 |
| 8 | Elena Ridloff | Cfo Head Of Corp. Dev. | 38,532 | 0 | 38,532 | 0.2% | 03 Sep, 2025 |
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 |
|---|---|---|---|---|---|---|---|---|
| 07 Jul, 2026 | Peter A. Thompson | Director | Disposed S | 85,918 | $44.86 | $3.85Mn | 2,469,959 | Indirect |
| 30 Jun, 2026 | Peter A. Thompson | Director | Disposed S | 115,844 | $45.50 | $5.27Mn | 2,555,877 | Indirect |
| 17 Jun, 2026 | Capital Management, L.P. Ra | Director, TenPercentOwner | Acquired A | 17,340 | $0.00 | $0 | 17,340 | Indirect |
| 17 Jun, 2026 | Joanne L. Viney | Director | Acquired A | 17,340 | $0.00 | $0 | 17,340 | Direct |
| 17 Jun, 2026 | Laurie Stelzer | Director | Acquired A | 17,340 | $0.00 | $0 | 17,340 | Direct |
| 17 Jun, 2026 | Peter A. Thompson | Director | Acquired A | 17,340 | $0.00 | $0 | 17,340 | Direct |
| 17 Jun, 2026 | Harold Edward Fleming | Director | Acquired A | 17,340 | $0.00 | $0 | 17,340 | Direct |
| 17 Jun, 2026 | Marcella K. Ruddy | Director | Acquired A | 17,340 | $0.00 | $0 | 17,340 | Direct |
| 27 May, 2026 | Advisors Llc Orbimed | Director | Disposed S | 101 | $44.49 | $4.49K | 2,671,721 | Indirect |
| 27 May, 2026 | Peter A. Thompson | Director | Disposed S | 101 | $44.49 | $4.49K | 2,671,721 | Indirect |
| 07 May, 2026 | Peter A. Thompson | Director | Disposed S | 48,546 | $44.61 | $2.17Mn | 2,916,228 | Indirect |
| 08 May, 2026 | Peter A. Thompson | Director | Disposed S | 59,767 | $44.58 | $2.66Mn | 2,856,461 | Indirect |
| 11 May, 2026 | Peter A. Thompson | Director | Disposed S | 184,639 | $46.22 | $8.53Mn | 2,671,822 | Indirect |
| 17 Apr, 2026 | Peter A. Thompson | Director | Disposed S | 52,397 | $44.68 | $2.34Mn | 2,967,722 | Indirect |
| 18 Apr, 2026 | Peter A. Thompson | Director | Disposed S | 2,948 | $44.52 | $131.24K | 2,964,774 | Indirect |
| 14 Apr, 2026 | Peter A. Thompson | Director | Disposed S | 47,814 | $44.51 | $2.13Mn | 3,482,888 | Indirect |
| 14 Apr, 2026 | Advisors Llc Orbimed | Director | Disposed S | 47,814 | $44.51 | $2.13Mn | 3,482,888 | Indirect |
| 15 Apr, 2026 | Peter A. Thompson | Director | Disposed S | 235,863 | $44.64 | $10.53Mn | 3,247,025 | Indirect |
| 15 Apr, 2026 | Advisors Llc Orbimed | Director | Disposed S | 235,863 | $44.64 | $10.53Mn | 3,247,025 | Indirect |
| 16 Apr, 2026 | Peter A. Thompson | Director | Disposed S | 226,906 | $45.34 | $10.29Mn | 3,020,119 | Indirect |