C4 THERAPEUTICS INC CCCC
COM STK · Common Stock · CUSIP 12529R107 · ISIN US12529R1077
Company in Watertown, United States
- SectorHealth care
- IndustryBiological Products, (No Diagnostic Substances)
- HeadquartersWatertown, MA
- Founded2015
- Websitec4therapeutics.com
- FilingsSEC EDGAR
* Summed across managers. Shares that two managers' reports both contain – a subsidiary's holdings that its parent's report includes too, or a sub-adviser's in its client's – are counted once ($23.1k this quarter). Holder counts are more reliable. Shares outstanding: 123.0m as of 2026-07-31, from the company's own SEC filing; the percentage can still exceed 100%: lent-out shares are counted by the lender and the buyer, and some reports overlap without saying so. Implied quarter-end price ≈ $4.66. Options: 9 managers hold calls ($4.6m notional), 5 hold puts ($672.2k).
Trends to Q2 2026
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q3 2022 | 115 |
| Q4 2022 | 117 |
| Q1 2023 | 122 |
| Q2 2023 | 101 |
| Q3 2023 | 85 |
| Q4 2023 | 93 |
| Q1 2024 | 107 |
| Q2 2024 | 116 |
| Q3 2024 | 119 |
| Q4 2024 | 114 |
| Q1 2025 | 116 |
| Q2 2025 | 103 |
| Q3 2025 | 97 |
| Q4 2025 | 101 |
| Q1 2026 | 123 |
| Q2 2026 | 148 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| Q3 2024 | 65 | 56 |
| Q4 2024 | 54 | 63 |
| Q1 2025 | 64 | 50 |
| Q2 2025 | 56 | 70 |
| Q3 2025 | 48 | 63 |
| Q4 2025 | 67 | 36 |
| Q1 2026 | 69 | 43 |
| Q2 2026 | 105 | 53 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q3 2025 | $806.3k | $645.2k | 0.80 |
| Q4 2025 | $737.6k | $151.8k | 0.21 |
| Q1 2026 | $1.0m | $352.1k | 0.35 |
| Q2 2026 | $4.6m | $672.2k | 0.15 |
Biggest buyers
| BlackRock, Inc. | Added | +5.8m |
| Squadron Capital Management LLC | Added | +5.0m |
| Ikarian Capital, LLC | New | +2.4m |
| Candriam S.C.A. | New | +1.8m |
| STATE STREET CORP | Added | +1.7m |
| CITADEL ADVISORS LLC | Added | +1.7m |
| Patient Square Capital LP | New | +1.6m |
| GEODE CAPITAL MANAGEMENT, LLC | Added | +1.6m |
| JPMORGAN CHASE & CO | Added | +1.5m |
| HighVista Strategies LLC | New | +1.3m |
Biggest sellers
| RENAISSANCE TECHNOLOGIES LLC | Reduced | -1.3m |
| MILLENNIUM MANAGEMENT LLC | Reduced | -1.2m |
| JANE STREET GROUP, LLC | Reduced | -944.1k |
| ORBIMED ADVISORS LLC | Sold out | -856.4k |
| Soleus Capital Management, L.P. | Reduced | -426.0k |
| WELLS FARGO & COMPANY/MN | Reduced | -415.2k |
| STEMPOINT CAPITAL LP | Reduced | -382.8k |
| Qube Research & Technologies Ltd | Reduced | -381.6k |
| 683 Capital Management, LLC | Sold out | -300.0k |
| BARCLAYS PLC | Reduced | -243.4k |
Biggest calls
| Squadron Capital Management LLC | New | $1.9m400.0k shares |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Added | $1.2m259.3k shares |
| Caption Management, LLC | New | $825.7k176.8k shares |
| JANE STREET GROUP, LLC | Reduced | $234.9k50.3k shares |
| SIMPLEX TRADING, LLC | Added | $140.6k30.1k shares |
| CITADEL ADVISORS LLC | Reduced | $114.9k24.6k shares |
| GROUP ONE TRADING LLC | Reduced | $99.5k21.3k shares |
| HRT FINANCIAL LP | Reduced | $89.0k19.2k shares |
| Walleye Capital LLC | Reduced | $1.4k300 shares |
Biggest puts
| CITADEL ADVISORS LLC | Added | $336.7k72.1k shares |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | New | $178.9k38.3k shares |
| SIMPLEX TRADING, LLC | New | $80.8k17.3k shares |
| HRT FINANCIAL LP | Reduced | $53.0k11.4k shares |
| GROUP ONE TRADING LLC | Added | $22.9k4.9k shares |
Options at notional value: the value of the shares the contracts control, as filers report them, not what the options cost. Not included in the holders, shares or buying above.
Major shareholders (over 5%)
Anyone who owns more than 5% of a class of the company's shares has to say so: on Schedule 13D if they may try to influence or control the company, on 13G if they're a passive investor, and update it as the stake changes. Each holder's latest filing, from 19 Dec 2024 on; percentages are of the share class, as the holder worked them out.
| Holder | Stake |
|---|---|
| Lynx1 Capital Management LP 13G · passive investor +2.7 pts · filed 2026-08-14 | 10.0% |
| Soleus Capital Master Fund, L.P. 13G · passive investor filed 2026-02-12 | 10.0% |
| RA CAPITAL MANAGEMENT, L.P. 13G · passive investor no change · filed 2026-08-14 | 9.9% |
| Sirenia Capital Management LP 13G · institution new · filed 2026-05-15 | 9.9% |
| Squadron Capital Management LLC 13G · institution +1.9 pts · filed 2026-08-14 | 6.9% |
| BlackRock, Inc. 13G · institution +4.4 pts · filed 2026-07-27 | 6.9% |
| Bain Capital Life Sciences Fund II, L.P. 13G · passive investor new · filed 2025-10-24 | 6.2% |
Fell to 5% or below in the last year: MORGAN STANLEY (8.0%, 2026-08-12), Point72 Asset Management, L.P. (0.2%, 2026-05-15), WASATCH ADVISORS LP (4.7%, 2026-04-22), ORBIMED ADVISORS LLC (1.0%, 2026-02-17)
Insider purchases and sales since 1 Apr 2026
Shares bought or sold by the company's own officers, directors and 10% owners, in the open market or privately, as they reported to the SEC on Form 4 (due within two business days of the trade). Grants, option exercises, shares withheld for tax and gifts aren't included.
Officers and directors buying vs selling
Number of people, by quarter (10% owners not included)
Numbers
| Quarter | Buying | Bought | Selling | Sold | Sold under a plan |
|---|---|---|---|---|---|
| Q4 2024 | 0 | — | 0 | — | — |
| Q1 2025 | 0 | — | 1 | $3.7k | $3.7k |
| Q2 2025 | 0 | — | 0 | — | — |
| Q3 2025 | 0 | — | 0 | — | — |
| Q4 2025 | 0 | — | 0 | — | — |
| Q1 2026 | 0 | — | 1 | $22.2k | — |
| Q2 2026 | 0 | — | 0 | — | — |
| Q3 2026 | 0 | — | 0 | — | — |
None reported since 1 Apr 2026.
Holders, Q2 2026
| Manager | Shares | Change |
|---|---|---|
| MORGAN STANLEY 0.00% of their portfolio | 8.9m $41.4m | Reduced -205.1k |
| RA CAPITAL MANAGEMENT, L.P. 0.32% of their portfolio | 8.0m $37.4m | Unchanged |
| BlackRock, Inc. 0.00% of their portfolio | 7.9m $36.9m | Added +5.8m |
| Lynx1 Capital Management LP 3.95% of their portfolio | 7.3m $34.2m | Added +327.8k |
| Squadron Capital Management LLC 11.51% of their portfolio | 7.2m $33.6m | Added +5.0m |
| Bain Capital Life Sciences Investors, LLC 1.99% of their portfolio | 7.2m $33.5m | Unchanged |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 4.7m $20.7m | Added +1.5m |
| VANGUARD CAPITAL MANAGEMENT LLC 0.00% of their portfolio | 4.4m $20.6m | Added +555.9k |
| CITADEL ADVISORS LLC 0.01% of their portfolio | 4.2m $19.6m | Added +1.7m |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 3.5m $16.5m | Added +1.1m |
| WASATCH ADVISORS LP 0.11% of their portfolio | 3.5m $16.5m | Added +560.9k |
| TWO SIGMA INVESTMENTS, LP 0.01% of their portfolio | 3.5m $16.2m | Added +434.1k |
| Soleus Capital Management, L.P. 0.54% of their portfolio | 3.4m $15.8m | Reduced -426.0k |
| SILVERARC CAPITAL MANAGEMENT, LLC 1.58% of their portfolio | 3.0m $14.2m | Added +1.1m |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 2.7m $12.4m | Added +297.1k |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 2.5m $11.8m | Added +1.6m |
| Ikarian Capital, LLC 1.86% of their portfolio | 2.4m $11.4m | New |
| STATE STREET CORP 0.00% of their portfolio | 2.1m $9.9m | Added +1.7m |
| ACADIAN ASSET MANAGEMENT LLC 0.01% of their portfolio | 1.8m $8.4m | Reduced -84.7k |
| Candriam S.C.A. 0.04% of their portfolio | 1.8m $8.4m | New |
| D. E. Shaw & Co., Inc. 0.01% of their portfolio | 1.7m $8.1m | Added +680.7k |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.01% of their portfolio | 1.7m $8.1m | Added +445.4k |
| Patient Square Capital LP 1.16% of their portfolio | 1.6m $7.5m | New |
| HighVista Strategies LLC 1.44% of their portfolio | 1.3m $6.3m | New |
| RENAISSANCE TECHNOLOGIES LLC 0.01% of their portfolio | 1.2m $5.6m | Reduced -1.3m |
| DIMENSIONAL FUND ADVISORS LP 0.00% of their portfolio | 1.2m $5.5m | Added +746.0k |
| NORTHERN TRUST CORP 0.00% of their portfolio | 1.2m $5.4m | Added +971.1k |
| CONGRESS ASSET MANAGEMENT CO 0.03% of their portfolio | 1.0m $4.7m | Added +172.8k |
| FMR LLC 0.00% of their portfolio | 894.1k $4.2m | Added +621.7k |
| UBS Group AG 0.00% of their portfolio | 829.0k $3.9m | Added +613.1k |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 781.1k $3.6m | Added +328.8k |
| BOOTHBAY FUND MANAGEMENT, LLC 0.06% of their portfolio | 736.3k $3.4m | New |
| VANGUARD PORTFOLIO MANAGEMENT LLC 0.00% of their portfolio | 680.1k $3.2m | New |
| VANGUARD FIDUCIARY TRUST CO 0.00% of their portfolio | 609.1k $2.8m | Added +125.0k |
| ExodusPoint Capital Management, LP 0.03% of their portfolio | 580.2k $2.7m | Added +532.7k |
| Velan Capital Investment Management LP 1.63% of their portfolio | 570.0k $2.7m | New |
| STEMPOINT CAPITAL LP 0.42% of their portfolio | 523.6k $2.4m | Reduced -382.8k |
| Rockefeller Capital Management L.P. 0.00% of their portfolio | 495.8k $2.3m | New |
| Nuveen, LLC 0.00% of their portfolio | 484.0k $2.3m | New |
| WELLS FARGO & COMPANY/MN 0.00% of their portfolio | 452.7k $2.1m | Reduced -415.2k |
| Man Group plc 0.00% of their portfolio | 408.6k $1.9m | Added +152.2k |
| PLATINUM INVESTMENT MANAGEMENT LTD 0.44% of their portfolio | 384.8k $1.8m | Unchanged |
| Seven Fleet Capital Management LP 0.29% of their portfolio | 381.2k $1.8m | Added +324.1k |
| Qube Research & Technologies Ltd 0.00% of their portfolio | 370.6k $1.7m | Reduced -381.6k |
| Atom Investors LP 0.15% of their portfolio | 364.4k $1.7m | Added +228.3k |
| Susquehanna Portfolio Strategies, LLC 0.02% of their portfolio | 335.1k $1.6m | Added +74.8k |
| ADAGE CAPITAL PARTNERS GP, L.L.C. 0.00% of their portfolio | 325.0k $1.5m | New |
| JANE STREET GROUP, LLC 0.00% of their portfolio | 302.8k $1.4m | Reduced -944.1k |
| Connor, Clark & Lunn Investment Management Ltd. 0.00% of their portfolio | 300.7k $1.4m | Added +23.6k |
| ADAR1 Capital Management, LLC 0.06% of their portfolio | 292.0k $1.4m | Added +249.0k |
| Invesco Ltd. 0.00% of their portfolio | 290.2k $1.4m | Added +45.7k |
| PANAGORA ASSET MANAGEMENT INC 0.00% of their portfolio | 264.9k $1.2m | Added +178.2k |
| LPL Financial LLC 0.00% of their portfolio | 253.2k $1.2m | Added +6.4k |
| Bank of New York Mellon Corp 0.00% of their portfolio | 249.5k $1.2m | New |
| WELLINGTON MANAGEMENT GROUP LLP 0.00% of their portfolio | 227.8k $1.1m | New |
| MARSHALL WACE, LLP 0.00% of their portfolio | 227.0k $1.1m | Added +71.5k |
| MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio | 215.4k $1.0m | Reduced -1.2m |
| Jump Financial, LLC 0.01% of their portfolio | 182.7k $853.2k | New |
| Point72 Asset Management, L.P. 0.00% of their portfolio | 174.0k $812.4k | Added +4.9k |
| Squarepoint Ops LLC 0.00% of their portfolio | 170.8k $797.8k | Added +130.2k |
| PRICE T ROWE ASSOCIATES INC /MD/ 0.00% of their portfolio | 155.9k $728.0k | Added +84.3k |
| Headlands Technologies LLC 0.08% of their portfolio | 154.0k $719.0k | New |
| AMERICAN CENTURY COMPANIES INC 0.00% of their portfolio | 150.7k $703.7k | Added +65.2k |
| XTX Topco Ltd 0.01% of their portfolio | 135.4k $632.5k | Added +88.3k |
| Palumbo Wealth Management LLC 0.13% of their portfolio | 132.4k $618.4k | New |
| RHUMBLINE ADVISERS 0.00% of their portfolio | 131.9k $615.9k | Added +129.2k |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC 0.01% of their portfolio | 131.1k $612.2k | Unchanged |
| Walleye Capital LLC 0.00% of their portfolio | 115.1k $537.6k | Reduced -124.0k |
| ALPS ADVISORS INC 0.00% of their portfolio | 112.2k $524.0k | New |
| CANADA PENSION PLAN INVESTMENT BOARD 0.00% of their portfolio | 101.5k $474.0k | Reduced -34.1k |
| DEUTSCHE BANK AG\ 0.00% of their portfolio | 98.9k $461.7k | New |
| Virtu Financial LLC 0.01% of their portfolio | 98.1k $458.0k | New |
| Verition Fund Management LLC 0.00% of their portfolio | 95.0k $443.6k | New |
| Vienna Powszechne Towarzystwo Emerytalne S.A. Vienna Insurance Group 0.10% of their portfolio | 85.0k $396.9k | Unchanged |
| BARCLAYS PLC 0.00% of their portfolio | 74.5k $348.0k | Reduced -243.4k |
| BNP PARIBAS FINANCIAL MARKETS 0.00% of their portfolio | 74.4k $347.3k | Reduced -116.0k |
| Crestwood Advisors Group, LLC 0.00% of their portfolio | 66.5k $310.7k | Unchanged |
| INTREPID FAMILY OFFICE LLC 0.28% of their portfolio | 65.0k $303.6k | Added +5.0k |
| CV Advisors LLC 0.06% of their portfolio | 65.0k $303.6k | New |
| ALLIANCEBERNSTEIN L.P. 0.00% of their portfolio | 64.8k $170.4k | New |
| MetLife Investment Management, LLC 0.00% of their portfolio | 61.4k $286.7k | New |
| Jain Global LLC 0.00% of their portfolio | 57.6k $268.8k | Reduced -4.8k |
| Thrivent Financial for Lutherans 0.00% of their portfolio | 52.8k $247.0k | New |
| CITIGROUP INC 0.00% of their portfolio | 49.4k $230.6k | Added +7.0k |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. 0.00% of their portfolio | 46.5k $217.0k | New |
| SEI INVESTMENTS CO 0.00% of their portfolio | 42.4k $197.9k | Added +17.2k |
| Quadrature Capital Ltd 0.00% of their portfolio | 36.7k $171.5k | Reduced -26.0k |
| Caption Management, LLC 0.01% of their portfolio | 35.0k $163.4k | New |
| Vanguard Global Advisers, LLC 0.00% of their portfolio | 33.8k $158.0k | Unchanged |
| Dynamic Technology Lab Private Ltd 0.03% of their portfolio | 32.8k $153.0k | New |
| PRUDENTIAL FINANCIAL INC 0.00% of their portfolio | 31.2k $145.9k | Added +15.3k |
| Police & Firemen's Retirement System of New Jersey 0.00% of their portfolio | 29.9k $139.6k | New |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE 0.00% of their portfolio | 27.5k $128.5k | New |
| JACOBS LEVY EQUITY MANAGEMENT, INC 0.00% of their portfolio | 25.1k $117.3k | Reduced -239.5k |
| Cresset Asset Management, LLC 0.00% of their portfolio | 25.0k $116.8k | Unchanged |
| NEW YORK STATE COMMON RETIREMENT FUND 0.00% of their portfolio | 24.1k $112.5k | New |
| StoneX Group Inc. 0.00% of their portfolio | 22.4k $102.3k | New |
| GROUP ONE TRADING LLC 0.00% of their portfolio | 21.8k $101.7k | New |
| Scientech Research LLC 0.08% of their portfolio | 21.3k $99.3k | New |
| Quantbot Technologies LP 0.00% of their portfolio | 20.8k $97.3k | New |