CytomX Therapeutics, Inc.
US ˙ NasdaqGS ˙ US23284F1057

SecurityCTMX / CytomX Therapeutics, Inc.
InstitutionPerceptive Advisors Llc
ManagerJoseph Edelman
Latest Disclosed Ownership10,098,824 shares
Ownership 4.60%
Perceptive Advisors Llc ownership in CTMX / CytomX Therapeutics, Inc.

2026-05-15 - Perceptive Advisors Llc has filed an SCHEDULE 13G/A form with the Securities and Exchange Commission (SEC) disclosing ownership of 10,098,824 shares of CytomX Therapeutics, Inc. (US:CTMX). This represents 4.6 percent ownership of the company. In their previous filing dated 2025-08-21 , Perceptive Advisors Llc had reported owning 9,680,185 shares, indicating an increase of 4.32 percent.

Institutional Ownership: 13D/G Filings

This table shows a history of the 13D/G filings made by the investor and/or investor group. Note that the share values in this table are not directly comparable to any numbers shown in the 13F table (if any).

File
Date		Effective
Date		Form Prev
Shares		 Latest
Shares		 ΔShares
(Percent)		 Ownership
(Percent)		 ΔOwnership
(Percent)
2026-05-15 2026-05-15 13G/A 9,680,185 10,098,824 4.32 4.60 -22.03
2025-08-21 2025-08-21 13G 2,577,043 9,680,185 275.63 5.90 37.21
2021-02-16 2021-02-16 13G/A 3,253,923 2,577,043 -20.80 4.30 -40.28
2020-02-14 2020-02-14 13G/A 2,991,715 3,253,923 8.76 7.20 10.77
2019-02-14 2019-02-14 13G/A 2,490,381 2,991,715 20.13 6.50 0.00
2018-02-14 2018-02-14 13G/A 2,165,381 2,490,381 15.01 6.50 16.07
2017-12-18 2017-12-18 13G 2,165,381 5.60

Important Note: One of the primary uses of the 13D/G filings is to evaluate the ability of a firm to control a company (ie, the "beneficial ownership"). To that end, firms are required to report not just direct holdings in companies, but indirect holdings that they control. For investment firms, these indirect holdings can include shares in funds they manage, advisory accounts, and in the case of activist campaigns, pledged votes. Therefore, share counts listed in 13D/G filings can differ significantly than share counts listed in 13F filings.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-29 2026-03-31 13F/A-1 CYTOMX THERAPEUTICS COM 23284F105 10,098,824 418,639 4.32 47,464 15.10 0.9275
2026-05-15 2026-03-31 13F CYTOMX THERAPEUTICS COM 23284F105 10,098,824 418,639 47,464 0.9287
2026-02-17 2025-12-31 13F CYTOMX THERAPEUTICS COM 23284F105 9,680,185 0 0.00 41,238 33.54 0.7350
2025-11-14 2025-09-30 13F CYTOMX THERAPEUTICS COM 23284F105 9,680,185 2,686,539 38.41 30,880 94.51 0.8917
2025-08-14 2025-06-30 13F CYTOMX THERAPEUTICS COM 23284F105 6,993,646 5,352,689 326.19 15,876 52.84 0.5886
2021-08-17 2021-06-30 13F/A-1 CYTOMX THERAPEUTICS COM 23284F105 1,640,957 -513,017 -23.82 10,387 -37.62 0.1348
2021-08-16 2021-06-30 13F CYTOMX THERAPEUTICS COM 23284F105 1,640,957 -513,017 10,387 0.1351
2021-08-13 2021-03-31 13F/A-2 CYTOMX THERAPEUTICS COM 23284F105 2,153,974 -423,069 -16.42 16,650 -1.36 0.2106
2021-06-10 2021-03-31 13F/A-1 CYTOMX THERAPEUTICS COM 23284F105 2,153,974 0 16,650 0.2100
2021-05-17 2021-03-31 13F CYTOMX THERAPEUTICS COM 23284F105 2,153,974 -423,069 16,650 0.2104
2021-02-16 2020-12-31 13F CYTOMX THERAPEUTICS COM 23284F105 2,577,043 0 0.00 16,880 -1.50 0.1811
2020-11-16 2020-09-30 13F CYTOMX THERAPEUTICS COM 23284F105 2,577,043 0 0.00 17,137 -20.17 0.2502
2020-08-17 2020-06-30 13F/A-1 CYTOMX THERAPEUTICS COM 23284F105 2,577,043 -676,880 -20.80 21,467 -13.99 0.3479
2020-08-14 2020-06-30 13F CYTOMX THERAPEUTICS COM 23284F105 2,577,043 -676,880 21,467 348,687.8118
2020-05-18 2020-03-31 13F/A-1 CYTOMX THERAPEUTICS COM 23284F105 3,253,923 0 0.00 24,958 -7.70 0.6500
2020-05-15 2020-03-31 13F CYTOMX THERAPEUTICS COM 23284F105 3,253,923 0 24,958 650,023.7528
2020-02-19 2019-12-31 13F/A-1 CYTOMX THERAPEUTICS COM 23284F105 3,253,923 0 0.00 27,040 12.60 0.5371
2020-02-14 2019-12-31 13F CYTOMX THERAPEUTICS COM 23284F105 3,253,923 0 27,040 436,542.1278
2019-11-14 2019-09-30 13F CYTOMX THERAPEUTICS COM 23284F105 3,253,923 100,000 3.17 24,014 -32.14 0.6470
2019-08-14 2019-06-30 13F CYTOMX THERAPEUTICS COM 23284F105 3,153,923 -20,000 -0.63 35,387 3.71 0.8120
2019-05-16 2019-03-31 13F/A-1 CYTOMX THERAPEUTICS COM 23284F105 3,173,923 262,208 9.01 34,120 -21.72 0.9627
2019-05-15 2019-03-31 13F CYTOMX THERAPEUTICS COM 23284F105 3,173,923 34,120
2019-02-14 2018-12-31 13F CYTOMX THERAPEUTICS COM 23284F105 2,911,715 250,000 9.39 43,588 -11.48 1.6589
2018-11-14 2018-09-30 13F CYTOMX THERAPEUTICS COM 23284F105 2,661,715 740,000 38.51 49,242 12.09 1.3167
2018-11-01 2018-06-30 13F/A-1 CYTOMX THERAPEUTICS COM 23284F105 1,921,715 -287,097 -13.00 43,930 -30.09 1.1517
2018-08-14 2018-06-30 13F CYTOMX THERAPEUTICS COM 23284F105 1,921,715 -287,097 43,930
2018-05-15 2018-03-31 13F CYTOMX THERAPEUTICS COM 23284F105 2,208,812 -281,569 -11.31 62,841 19.54 1.7601
2018-02-14 2017-12-31 13F CYTOMX THERAPEUTICS COM 23284F105 2,490,381 1,100,000 79.12 52,571 108.09 1.7426
2017-11-14 2017-09-30 13F/A-1 CYTOMX THERAPEUTICS COM 23284F105 1,390,381 0 0.00 25,263 17.23 0.9651
2017-11-14 2017-09-30 13F CYTOMX THERAPEUTICS COM 23284F105 1,390,381 25,263
2017-08-14 2017-06-30 13F CYTOMX THERAPEUTICS COM 23284F105 1,390,381 -140,278 -9.16 21,550 -18.48 1.0844
2017-05-15 2017-03-31 13F CYTOMX THERAPEUTICS SHARES COM 23284F105 1,530,659 606,896 65.70 26,434 160.38 1.5058
2017-05-02 2016-12-31 13F/A-3 CYTOMX THERAPEUTICS COM 23284F105 923,763 923,763 -39.65 10,152 -61.59 0.7219
2017-03-20 2016-12-31 13F/A-2 CYTOMX THERAPEUTICS COM 23284F105 923,763 0 10,152 0.7224
2017-03-09 2016-12-31 13F/A-1 CYTOMX THERAPEUTICS COM 23284F105 923,763 0 10,152 0.7224
2017-02-14 2016-12-31 13F CYTOMX THERAPEUTICS COM 23284F105 923,763 10,152
2016-11-14 2016-09-30 13F CYTOMX THERAPEUTICS COM 23284F105 0 -742,021 -100.00 0 -100.00
2016-08-11 2016-06-30 13F CYTOMX THERAPEUTICS COM 23284F105 742,021 0 0.00 7,579 -20.82 0.5254
2016-05-16 2016-03-31 13F CYTOMX THERAPEUTICS COM 23284F105 742,021 99,974 15.57 9,572 -28.56 0.8396
2016-02-16 2015-12-31 13F CYTOMX THERAPEUTICS COM 23284F105 642,047 642,047 13,399 0.9913
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.