CYTOMX THERAPEUTICS INC CTMX
COM · Common Stock · CUSIP 23284F105 · ISIN US23284F1057
Company in South San Francisco, United States
- SectorHealth care
- IndustryPharmaceutical Preparations
- HeadquartersSouth San Francisco, CA
- Founded2008
- Websitecytomx.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 ($283.6k this quarter). Holder counts are more reliable. Shares outstanding: 170.2m as of 2025-12-31, 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 ≈ $4.26. Options: 8 managers hold calls ($6.1m notional), 4 hold puts ($359.5k).
Trends to Q4 2025
Institutional holders
Managers reporting a position, each quarter
Numbers
| Quarter | Holders |
|---|---|
| Q3 2022 | 85 |
| Q4 2022 | 81 |
| Q1 2023 | 77 |
| Q2 2023 | 68 |
| Q3 2023 | 63 |
| Q4 2023 | 69 |
| Q1 2024 | 89 |
| Q2 2024 | 75 |
| Q3 2024 | 70 |
| Q4 2024 | 71 |
| Q1 2025 | 67 |
| Q2 2025 | 84 |
| Q3 2025 | 103 |
| Q4 2025 | 122 |
Buyers vs sellers
Managers adding to or starting a position, vs cutting or selling out
Numbers
| Quarter | Bought or added | Cut or sold out |
|---|---|---|
| Q1 2024 | 47 | 32 |
| Q2 2024 | 42 | 51 |
| Q3 2024 | 27 | 36 |
| Q4 2024 | 32 | 31 |
| Q1 2025 | 27 | 36 |
| Q2 2025 | 56 | 29 |
| Q3 2025 | 61 | 37 |
| Q4 2025 | 71 | 46 |
Calls vs puts
Options held, notional value, last 4 quarters. P/C = puts ÷ calls
Numbers
| Quarter | Calls | Puts | P/C |
|---|---|---|---|
| Q1 2025 | $9.1k | $30.5k | 3.33 |
| Q2 2025 | $2.1m | $362.1k | 0.17 |
| Q3 2025 | $6.8m | $1.0m | 0.15 |
| Q4 2025 | $6.1m | $359.5k | 0.06 |
Biggest buyers
| FMR LLC | Added | +9.3m |
| Kynam Capital Management, LP | Added | +5.3m |
| STATE STREET CORP | Added | +4.5m |
| Eversept Partners, LP | New | +2.5m |
| Financial Engines Advisors L.L.C. | Added | +2.4m |
| GOLDMAN SACHS GROUP INC | Added | +2.0m |
| BlackRock, Inc. | Added | +1.3m |
| Point72 Asset Management, L.P. | Added | +1.1m |
| STEMPOINT CAPITAL LP | New | +1.0m |
| Qube Research & Technologies Ltd | Added | +938.6k |
Biggest sellers
| TANG CAPITAL MANAGEMENT LLC | Sold out | -11.1m |
| ORBIMED ADVISORS LLC | Reduced | -4.9m |
| RTW INVESTMENTS, LP | Sold out | -3.5m |
| RA CAPITAL MANAGEMENT, L.P. | Sold out | -2.7m |
| RENAISSANCE TECHNOLOGIES LLC | Sold out | -2.5m |
| CITADEL ADVISORS LLC | Reduced | -1.5m |
| MILLENNIUM MANAGEMENT LLC | Reduced | -1.1m |
| Prosight Management, LP | Sold out | -564.8k |
| Inspire Investing, LLC | Reduced | -522.5k |
| VANGUARD GROUP INC | Reduced | -472.2k |
Biggest calls
| Balyasny Asset Management L.P. | Unchanged | $3.8m900.0k shares |
| ADAR1 Capital Management, LLC | New | $426.0k100.0k shares |
| SIMPLEX TRADING, LLC | Reduced | $421.7k99.0k shares |
| JANE STREET GROUP, LLC | Added | $382.5k89.8k shares |
| CITADEL ADVISORS LLC | Reduced | $337.8k79.3k shares |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Reduced | $331.9k77.9k shares |
| GROUP ONE TRADING LLC | Reduced | $252.2k59.2k shares |
| J. Goldman & Co LP | New | $157.6k37.0k shares |
Biggest puts
| CITADEL ADVISORS LLC | Added | $218.1k51.2k shares |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP | Reduced | $87.8k20.6k shares |
| GROUP ONE TRADING LLC | Reduced | $48.6k11.4k shares |
| SIMPLEX TRADING, LLC | Reduced | $5.1k1.2k 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 |
|---|---|
| FMR LLC 13G · institution +2.2 pts · filed 2026-02-05 | 14.6% |
| Kynam Capital Management, LP 13G · institution +3.1 pts · filed 2026-08-14 | 10.0% |
| BlackRock, Inc. 13G · institution new · filed 2026-07-27 | 7.6% |
| Longitude Capital Partners V, LLC 13G · passive investor -0.3 pts · filed 2026-05-15 | 7.0% |
| BANK OF AMERICA CORP /DE/ 13G · institution -1.6 pts · filed 2026-10-28 | 5.4% |
| STATE STREET CORP 13G · institution new · filed 2026-08-07 | 5.4% |
Fell to 5% or below in the last year: Point72 Asset Management, L.P. (3.6%, 2026-08-14), Venrock Healthcare Capital Partners III, L.P. (4.6%, 2026-05-15), Seven Fleet Capital Management LP (0.5%, 2026-05-15), PERCEPTIVE ADVISORS LLC (4.6%, 2026-05-15), VANGUARD GROUP INC (0.0%, 2026-03-26), TANG CAPITAL MANAGEMENT LLC (0.0%, 2026-02-17), ORBIMED ADVISORS LLC (2.1%, 2026-02-17)
Insider purchases and sales in Q4 2025
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 |
|---|---|---|---|---|---|
| Q1 2024 | 0 | — | 5 | $99.9k | — |
| Q2 2024 | 0 | — | 0 | — | — |
| Q3 2024 | 0 | — | 5 | $24.7k | — |
| Q4 2024 | 0 | — | 0 | — | — |
| Q1 2025 | 0 | — | 5 | $48.0k | — |
| Q2 2025 | 0 | — | 3 | $220.1k | — |
| Q3 2025 | 0 | — | 0 | — | — |
| Q4 2025 | 0 | — | 1 | $462.1k | $462.1k |
| Date | Insider | Trade | Value |
|---|---|---|---|
| 2025-11-06 | McCarthy Sean A. CEO, director | Sold plan | $462.1k101.8k shares |
Their holding: how much the trade added to or took from the insider's holding (direct, or the trust or fund named). The same trade is sometimes reported by more than one insider, such as a fund and the director who represents it; totals count it once. A value is left blank where the reported price is far from the market price (usually a typo).
Holders, Q4 2025
| Manager | Shares | Change |
|---|---|---|
| FMR LLC 0.01% of their portfolio | 24.7m $105.2m | Added +9.3m |
| Venrock Adviser, LLC 3.27% of their portfolio | 15.6m $66.3m | Unchanged |
| PERCEPTIVE ADVISORS LLC 0.76% of their portfolio | 9.7m $41.2m | Unchanged |
| Kynam Capital Management, LP 2.49% of their portfolio | 9.0m $38.2m | Added +5.3m |
| VANGUARD GROUP INC 0.00% of their portfolio | 8.5m $36.1m | Reduced -472.2k |
| Commodore Capital LP 2.18% of their portfolio | 7.7m $32.8m | Unchanged |
| Point72 Asset Management, L.P. 0.03% of their portfolio | 5.2m $22.1m | Added +1.1m |
| STATE STREET CORP 0.00% of their portfolio | 5.1m $21.9m | Added +4.5m |
| BAKER BROS. ADVISORS LP 0.11% of their portfolio | 4.3m $18.1m | Unchanged |
| ADAR1 Capital Management, LLC 1.33% of their portfolio | 4.2m $17.8m | Added +137.4k |
| Balyasny Asset Management L.P. 0.03% of their portfolio | 3.9m $16.5m | Reduced -40.9k |
| Financial Engines Advisors L.L.C. 0.03% of their portfolio | 3.8m $16.3m | Added +2.4m |
| BlackRock, Inc. 0.00% of their portfolio | 3.7m $15.6m | Added +1.3m |
| ORBIMED ADVISORS LLC 0.31% of their portfolio | 3.5m $15.0m | Reduced -4.9m |
| Ikarian Capital, LLC 1.75% of their portfolio | 3.2m $13.5m | Reduced -200.0k |
| Vivo Capital, LLC 0.79% of their portfolio | 2.9m $12.3m | Unchanged |
| Eversept Partners, LP 0.60% of their portfolio | 2.5m $10.7m | New |
| GOLDMAN SACHS GROUP INC 0.00% of their portfolio | 2.5m $10.5m | Added +2.0m |
| Woodline Partners LP 0.04% of their portfolio | 2.3m $10.0m | Unchanged |
| TWO SIGMA INVESTMENTS, LP 0.01% of their portfolio | 1.6m $6.6m | Added +831.1k |
| GEODE CAPITAL MANAGEMENT, LLC 0.00% of their portfolio | 1.5m $6.5m | Reduced -43.6k |
| DIMENSIONAL FUND ADVISORS LP 0.00% of their portfolio | 1.3m $5.5m | Added +838.5k |
| MARSHALL WACE, LLP 0.00% of their portfolio | 1.2m $4.9m | Added +51.9k |
| Qube Research & Technologies Ltd 0.01% of their portfolio | 1.1m $4.5m | Added +938.6k |
| STEMPOINT CAPITAL LP 0.76% of their portfolio | 1.0m $4.4m | New |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP 0.01% of their portfolio | 981.6k $4.2m | Added +714.1k |
| BOOTHBAY FUND MANAGEMENT, LLC 0.10% of their portfolio | 894.7k $3.8m | Reduced -342.4k |
| BANK OF AMERICA CORP /DE/ 0.00% of their portfolio | 876.3k $3.7m | Reduced -128.9k |
| ACADIAN ASSET MANAGEMENT LLC 0.01% of their portfolio | 856.1k $3.6m | Added +202.3k |
| Exome Asset Management LLC 1.57% of their portfolio | 745.3k $3.2m | Unchanged |
| Elmind Capital, LP 0.88% of their portfolio | 700.0k $3.0m | First filing |
| JANE STREET GROUP, LLC 0.00% of their portfolio | 607.2k $2.6m | Added +205.9k |
| Assenagon Asset Management S.A. 0.00% of their portfolio | 592.7k $2.5m | Reduced -137.3k |
| FIRST TRUST ADVISORS LP 0.00% of their portfolio | 423.2k $1.8m | Added +21.3k |
| NORTHERN TRUST CORP 0.00% of their portfolio | 415.2k $1.8m | Added +25.5k |
| MORGAN STANLEY 0.00% of their portfolio | 401.2k $1.7m | Added +81.9k |
| SILVERARC CAPITAL MANAGEMENT, LLC 0.24% of their portfolio | 386.0k $1.6m | New |
| SCHULHOFF & CO INC 0.67% of their portfolio | 374.9k $1.6m | New |
| UBS Group AG 0.00% of their portfolio | 370.7k $1.6m | Added +340.6k |
| CITADEL ADVISORS LLC 0.00% of their portfolio | 342.3k $1.5m | Reduced -1.5m |
| BARCLAYS PLC 0.00% of their portfolio | 336.5k $1.4m | Added +335.0k |
| TWO SIGMA ADVISERS, LP 0.00% of their portfolio | 335.5k $1.4m | Added +295.5k |
| Bank of New York Mellon Corp 0.00% of their portfolio | 328.2k $1.4m | Added +75.6k |
| RAYMOND JAMES FINANCIAL INC 0.00% of their portfolio | 317.0k $1.4m | Added +23.4k |
| MILLENNIUM MANAGEMENT LLC 0.00% of their portfolio | 289.7k $1.2m | Reduced -1.1m |
| Rafferty Asset Management, LLC 0.00% of their portfolio | 273.6k $1.2m | New |
| AMERIPRISE FINANCIAL INC 0.00% of their portfolio | 229.6k $989.0k | Added +71.3k |
| PRELUDE CAPITAL MANAGEMENT, LLC 0.06% of their portfolio | 206.5k $879.8k | Unchanged |
| Informed Momentum Co LLC 0.10% of their portfolio | 203.8k $868.3k | New |
| HighVista Strategies LLC 0.21% of their portfolio | 193.9k $826.2k | Reduced -63.2k |
| SEI INVESTMENTS CO 0.00% of their portfolio | 124.1k $528.8k | New |
| LPL Financial LLC 0.00% of their portfolio | 113.4k $483.3k | Added +26.8k |
| CANADA PENSION PLAN INVESTMENT BOARD 0.00% of their portfolio | 104.2k $443.9k | New |
| Aspire Growth Partners LLC 0.30% of their portfolio | 102.3k $435.6k | Unchanged |
| NLB Skladi, upravljanje premozenja, d.o.o. 0.02% of their portfolio | 100.0k $426.0k | First filing |
| PROFUND ADVISORS LLC 0.01% of their portfolio | 98.6k $420.2k | New |
| CITIGROUP INC 0.00% of their portfolio | 96.3k $410.3k | Added +88.6k |
| OMERS ADMINISTRATION Corp 0.00% of their portfolio | 87.8k $374.0k | New |
| GSA CAPITAL PARTNERS LLP 0.03% of their portfolio | 81.9k $349.0k | Reduced -454.1k |
| Velan Capital Investment Management LP 0.20% of their portfolio | 80.0k $340.8k | Unchanged |
| HRT FINANCIAL LP 0.00% of their portfolio | 71.9k $306.0k | New |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC 0.00% of their portfolio | 68.7k $292.6k | Reduced -19.9k |
| Miller Financial Services LLC 0.34% of their portfolio | 68.0k $289.7k | Added +1.0k |
| Virtus Investment Advisers, LLC 0.07% of their portfolio | 63.5k $270.5k | New |
| Brooklyn Investment Group 0.01% of their portfolio | 61.5k $257.6k | New |
| Congress Park Capital LLC 0.07% of their portfolio | 58.9k $251.0k | Reduced -45.0k |
| Merit Financial Group, LLC 0.00% of their portfolio | 53.2k $226.8k | Unchanged |
| SG Americas Securities, LLC 0.00% of their portfolio | 53.1k $226.0k | New |
| Timothy G. Youngquist 2020 Irrevocable Trust 0.19% of their portfolio | 51.2k $217.9k | First filing |
| Hudson Bay Capital Management LP 0.00% of their portfolio | 51.0k $217.2k | New |
| Squarepoint Ops LLC 0.00% of their portfolio | 49.9k $212.6k | Added +2.2k |
| Seven Fleet Capital Management LP 0.14% of their portfolio | 48.9k $208.3k | First filing |
| Susquehanna Portfolio Strategies, LLC 0.00% of their portfolio | 48.0k $204.5k | Unchanged |
| XTX Topco Ltd 0.01% of their portfolio | 48.0k $204.4k | Added +18.7k |
| Formidable Asset Management, LLC 0.03% of their portfolio | 45.8k $194.9k | Reduced -72.6k |
| Tidal Investments LLC 0.00% of their portfolio | 45.8k $194.9k | Reduced -72.6k |
| Baader Bank Aktiengesellschaft 0.02% of their portfolio | 45.0k $191.7k | Not comparable |
| Private Advisor Group, LLC 0.00% of their portfolio | 44.0k $187.4k | Unchanged |
| Lighthouse Investment Partners, LLC 0.00% of their portfolio | 32.0k $136.5k | New |
| Cambria Investment Management, L.P. 0.01% of their portfolio | 31.3k $133.5k | New |
| Empowered Funds, LLC 0.00% of their portfolio | 31.3k $133.5k | New |
| China Universal Asset Management Co., Ltd. 0.01% of their portfolio | 27.6k $117.6k | New |
| Truvestments Capital LLC 0.02% of their portfolio | 27.4k $116.8k | Added +10.3k |
| Vanguard Personalized Indexing Management, LLC 0.00% of their portfolio | 26.8k $114.0k | Reduced -174 |
| Engineers Gate Manager LP 0.00% of their portfolio | 26.5k $113.1k | New |
| MANGROVE PARTNERS IM, LLC 0.01% of their portfolio | 26.3k $111.9k | New |
| HB Wealth Management, LLC 0.00% of their portfolio | 25.0k $106.5k | New |
| Tower Research Capital LLC (TRC) 0.00% of their portfolio | 24.8k $105.6k | Added +24.8k |
| HSBC HOLDINGS PLC 0.00% of their portfolio | 24.5k $104.2k | New |
| JPMORGAN CHASE & CO 0.00% of their portfolio | 24.4k $103.8k | Reduced -7.9k |
| SIMPLEX TRADING, LLC 0.00% of their portfolio | 24.1k $102.5k | New |
| Jefferies Financial Group Inc. 0.00% of their portfolio | 23.8k $101.2k | Reduced -29.1k |
| Ethos Financial Group, LLC 0.01% of their portfolio | 23.7k $100.9k | Unchanged |
| Mariner, LLC 0.00% of their portfolio | 22.2k $94.5k | Added +11.9k |
| Invesco Ltd. 0.00% of their portfolio | 22.0k $93.6k | Reduced -450 |
| State of Wyoming 0.01% of their portfolio | 21.5k $91.6k | New |
| Jain Global LLC 0.00% of their portfolio | 21.2k $90.4k | Reduced -12.4k |
| OSAIC HOLDINGS, INC. 0.00% of their portfolio | 19.4k $82.7k | Added +2.7k |
| Sanctuary Advisors, LLC 0.00% of their portfolio | 19.1k $81.5k | Reduced -15.5k |
| Forefront Analytics, LLC 0.07% of their portfolio | 18.7k $79.7k | Added +590 |