🕵️ C4 Therapeutics, Inc. ($CCCC)
SEC insider & ownership activity, last 12 months · CIK 1662579 · every row links its SEC filing
Over the last 12 months insiders sold $22K with no open-market buying against it. Reyno Leonard sold $22K in discretionary trades (Jan). 3 planned sales are pending, the largest $77K (Mark Mossler). No red-flag 8-Ks in the window.
🚨 1 signal active —
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Monthly net open-market insider flow, last 12 months (up = net buying)
Insider flow
0 buyers, $0 (0 lots) · 1 seller, $22K (1 lots)
| Insider | Buys | Bought | Sells | Sold | Last |
|---|---|---|---|---|---|
| Reyno Leonard | 0 | – | 1 | $22K | Jan 16, 2026 |
5%+ holders
| Holder | Stake | Class | Schedule | Event | |
|---|---|---|---|---|---|
| Soleus Capital Master Fund, L.P. | 10.0% | 13G | Feb 12, 2026 | filing ↗ | |
| Soleus Capital, LLC | 10.0% | 13G | Feb 12, 2026 | filing ↗ | |
| Soleus Capital Group, LLC | 10.0% | 13G | Feb 12, 2026 | filing ↗ | |
| Soleus Capital Management, L.P. | 10.0% | 13G | Feb 12, 2026 | filing ↗ | |
| Soleus GP, LLC | 10.0% | 13G | Feb 12, 2026 | filing ↗ | |
| Guy Levy | 10.0% | 13G | Feb 12, 2026 | filing ↗ | |
| LYNX1 Capital Management LP | 10.0% | 13G | Aug 14, 2026 | filing ↗ | |
| Weston Nichols | 10.0% | 13G | Aug 14, 2026 | filing ↗ | |
| RA Capital Management, L.P. | 9.9% | 13G | Aug 14, 2026 | filing ↗ | |
| Peter Kolchinsky | 9.9% | 13G | Aug 14, 2026 | filing ↗ | |
| Rajeev Shah | 9.9% | 13G | Aug 14, 2026 | filing ↗ | |
| RA Capital Healthcare Fund, L.P. | 9.9% | 13G | Aug 14, 2026 | filing ↗ | |
| Sirenia Capital Management LP | 9.9% | 13G | May 15, 2026 | filing ↗ | |
| Alex Silverstein | 9.9% | 13G | May 15, 2026 | filing ↗ | |
| Morgan Stanley | 8.0% | 13G | Aug 12, 2026 | filing ↗ | |
| Morgan Stanley Capital Services LLC | 7.9% | 13G | Aug 12, 2026 | filing ↗ | |
| Squadron Master Fund LP | 6.9% | 13G | Aug 14, 2026 | filing ↗ | |
| Squadron Capital Management LLC | 6.9% | 13G | Aug 14, 2026 | filing ↗ | |
| Matthew Sesterhenn | 6.9% | 13G | Aug 14, 2026 | filing ↗ | |
| William Blank | 6.9% | 13G | Aug 14, 2026 | filing ↗ | |
| BlackRock, Inc. | 6.9% | 13G | Jul 27, 2026 | filing ↗ | |
| Morgan Stanley | 6.7% | 13G | Aug 7, 2025 | filing ↗ | |
| BCLS II Equity Opportunities, LP | 6.2% | 13G | Oct 24, 2025 | filing ↗ | |
| Soleus Private Equity Fund III, L.P. | 5.9% | 13G | Feb 12, 2026 | filing ↗ | |
| Soleus Private Equity GP III, LLC | 5.9% | 13G | Feb 12, 2026 | filing ↗ | |
| Soleus PE GP III, LLC | 5.9% | 13G | Feb 12, 2026 | filing ↗ |
Planned insider sales (Form 144)
| Seller | Planned | Approx. sale date | |
|---|---|---|---|
| Mark Mossler | $18K | Aug 14, 2026 | filing ↗ |
| Jay Geldmacher | $1.9M | Aug 14, 2026 | filing ↗ |
| Mark Mossler | $61K | Aug 13, 2026 | filing ↗ |
| Mark Mossler | $77K | Aug 12, 2026 | filing ↗ |
| Mark Mossler | $35K | May 27, 2026 | filing ↗ |
| Jolie M. Siegel | $379K | Mar 9, 2026 | filing ↗ |
Material events (8-K)
| Item | Event date | |
|---|---|---|
| Earnings (2.02) | Aug 11, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Aug 11, 2026 | filing ↗ |
| Shareholder vote (5.07) | Jun 24, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Jun 24, 2026 | filing ↗ |
| Reg FD disclosure (7.01) | Jun 11, 2026 | filing ↗ |
| Other events (8.01) | Jun 11, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Jun 11, 2026 | filing ↗ |
| Officer/director changes (5.02) | May 15, 2026 | filing ↗ |
| Earnings (2.02) | May 12, 2026 | filing ↗ |
| Reg FD disclosure (7.01) | May 12, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | May 12, 2026 | filing ↗ |
| Charter/bylaw changes (5.03) | Apr 10, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Apr 10, 2026 | filing ↗ |
| Material agreement (1.01) | Apr 9, 2026 | filing ↗ |
| Reg FD disclosure (7.01) | Apr 9, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Apr 9, 2026 | filing ↗ |
| Earnings (2.02) | Feb 26, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Feb 26, 2026 | filing ↗ |
| Reg FD disclosure (7.01) | Jan 14, 2026 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Jan 14, 2026 | filing ↗ |
| Earnings (2.02) | Nov 6, 2025 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Nov 6, 2025 | filing ↗ |
| Other events (8.01) | Oct 16, 2025 | filing ↗ |
| Material agreement (1.01) | Oct 16, 2025 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Oct 16, 2025 | filing ↗ |
| Reg FD disclosure (7.01) | Oct 1, 2025 | filing ↗ |
| Other events (8.01) | Oct 1, 2025 | filing ↗ |
| Financial Statements and Exhibits (9.01) | Oct 1, 2025 | filing ↗ |
| Reg FD disclosure (7.01) | Sep 22, 2025 | filing ↗ |
| Other events (8.01) | Sep 22, 2025 | filing ↗ |