MarketPeel
Insider Trading Intelligence
MB

Marcia Belvin

CTMX
SVP, CHIEF SCIENTIFIC OFFICER · CYTOMX THERAPEUTICS, INC. · CIK 0001970752
FILING MIX · LIFETIME67%/33%
BUYS
20
SELLS
10
TOTAL VALUE
$294.1K
COMPANIES
1
ACTIVE SINCE
Mar 2023
HOLDINGS NOW
300,760
AVG SELL PX
$3.27
TRADE KIND
SHOWING 30 / 30
Trades · vs SPY
Loading price series…
Performance · forward returns vs SPY
4 backtested trades · 8 horizons · 5 pendingHow are these numbers computed? →
Forward-return performance of every backtestable P/S trade by Marcia Belvin, measured at 8 horizons from 7 days to 2 years. Deduped per economic event so co-filings count once. Excess return = trade return minus SPY return over the same window.
HORIZONTRADESWIN RATEINSIDER RETURNSPY RETURNMEAN EXCESSMEDIAN EXCESST-STAT
7d4+75.00%-8.93%+0.11%-9.04%-7.79%
14d4+100.00%-6.81%+0.09%-6.90%-7.23%
30d4+75.00%-6.28%-0.21%-6.06%-10.65%
60d4+75.00%+42.33%+6.58%+35.75%-22.54%
90d4+75.00%+51.22%+8.52%+42.70%-36.01%
180d4(1 pending)+33.33%+85.16%+13.59%+71.56%+57.20%
1y4(1 pending)+33.33%+192.82%+18.18%+174.64%-6.34%
2y4(3 pending)+0.00%+119.27%+29.57%+89.70%+89.70%
How to read this: Insider Returnis the average raw return of the filer's trades over the horizon. SPY Return is what SPY did over those same windows — reference only, not a comparison. The headline alpha number is Mean Excess = Insider − SPY; green means the filer beat SPY, red means they trailed it. Win rate is the share of individual trades where the filer beat SPY. T-statvalues above 2 mean the alpha is unlikely to be chance given the sample size. "Pending" counts trades where the horizon hasn't elapsed yet; their stats are not included in the row average.
Holdings over time
CTMX · 300,760 shares · as of Mar 17, 2026
083,063166,126249,189332,252202420252026SHARES HELD
Trading cadence · quarterly flow
BUY SELL
2023
2023
2023
2023
2024
2024
2024
2024
2025
2025
2025
2025
2026
FLOW · 20 buys / 10 sellsCOVERAGE · 13 quarters
Form 4 filings · all activity
COMPANYTYPESHARESPRICEVALUEHELD AFTERTRADE DATEFILEDDETAILS
CTMX
CYTOMX THERAPEUTICS, INC.
SALE
SVP, Chief Scientific Officer
31,492$6.42$202.3K300,760Mar 17, 2026Mar 19, 2026View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
250,000250,000Feb 2, 2026Feb 4, 2026View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
60,000332,252Feb 2, 2026Feb 4, 2026View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
18,15018,150Sep 26, 2025Sep 30, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
36,30036,300Sep 26, 2025Sep 30, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
SALE
SVP, Chief Scientific Officer
13,884$2.69$37.3K272,252Jun 16, 2025Jun 17, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASE
SVP, Chief Scientific Officer
37,500286,136Jun 13, 2025Jun 17, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
SALE
SVP, Chief Scientific Officer
37,5000Jun 13, 2025Jun 17, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
SALE
SVP, Chief Scientific Officer
19,512$0.60$11.7K248,636Mar 18, 2025Mar 20, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
115,000115,000Feb 4, 2025Feb 6, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
57,500263,148Feb 4, 2025Feb 6, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
115,000115,000Feb 4, 2025Feb 10, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
30,000205,648Feb 4, 2025Feb 6, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
140,000140,000Feb 4, 2025Feb 6, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
35,000210,648Feb 4, 2025Feb 10, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
150,000150,000Feb 4, 2025Feb 10, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
57,500268,148Feb 4, 2025Feb 10, 2025View →
CTMX
CYTOMX THERAPEUTICS, INC.
SALE
SVP, Chief Scientific Officer
11,2500Aug 20, 2024Aug 22, 2024View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASE
SVP, Chief Scientific Officer
11,250179,829Aug 20, 2024Aug 22, 2024View →
CTMX
CYTOMX THERAPEUTICS, INC.
SALE
SVP, Chief Scientific Officer
4,181$1.23$5.1K175,648Aug 20, 2024Aug 22, 2024View →
CTMX
CYTOMX THERAPEUTICS, INC.
SALE
SVP, Chief Scientific Officer
12,795$2.09$26.7K168,579Mar 19, 2024Mar 21, 2024View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
26,250181,374Jan 18, 2024Jan 19, 2024View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
122,500122,500Jan 18, 2024Jan 19, 2024View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
75,00075,000Jan 18, 2024Jan 19, 2024View →
CTMX
CYTOMX THERAPEUTICS, INC.
SALE
SVP, Chief Scientific Officer
4,077$1.38$5.6K155,124Dec 20, 2023Dec 22, 2023View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASE
SVP, Chief Scientific Officer
11,250159,201Dec 17, 2023Dec 19, 2023View →
CTMX
CYTOMX THERAPEUTICS, INC.
SALE
SVP, Chief Scientific Officer
11,25011,250Dec 17, 2023Dec 19, 2023View →
CTMX
CYTOMX THERAPEUTICS, INC.
SALE
SVP, Chief Scientific Officer
4,119$1.30$5.4K147,951Sep 22, 2023Sep 22, 2023View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
11,250152,070Sep 20, 2023Sep 22, 2023View →
CTMX
CYTOMX THERAPEUTICS, INC.
PURCHASEGRANT
Stock grant
60,000140,820Mar 22, 2023Mar 29, 2023View →
Other insiders · CTMX
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About this filer
CIK 0001970752
ROLE
SVP, Chief Scientific Officer
PRIMARY
CTMX
COMPANIES
1
ACTIVE SINCE
Mar 2023
MARKETPEEL · /INSIDER/0001970752DATA · SEC EDGAR · FORM 4 · CONSOLIDATED TAPE
FREE · DAILY · 6 AM ET

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