Summary
Updated Aug 30, 2026
Marcia Belvin is SVP, Chief Scientific Officer of CytomX Therapeutics, Inc. (CTMX). 3 SEC Form 4 filings on record going back to 2025, most recently on 19 March 2026. Most recent open-market trade: sold $202K of CTMX on 19 March 2026. Lifetime open-market sales: $202K.
Recent Transactions
2Every recent SEC Form 4 transaction Marcia Belvin has reported, most recent first.
Trading Pattern
InsiderAlpha's records for Marcia Belvin go back to 2025: 3 primary Form 4 filings, an average of 1.5 per year. No transaction on record carries a Rule 10b5-1 flag - the filings look discretionary rather than pre-scheduled, which makes their timing more informative as a signal.
Other Insiders Active in the Same Stocks
Insiders who reported open-market trades in the last 12 months at the companies Marcia Belvin files at. Multiple unrelated insiders buying the same stock within a short window, cluster buying, has historically been one of the strongest Form 4 signals.
- Sean A. McCarthy - $1.23M of CTMX open-market activity in the last 12 months
- Yu-Waye Chu - $137K of CTMX open-market activity in the last 12 months
- Christopher Ogden - $129K of CTMX open-market activity in the last 12 months
More Notable Insiders
Other corporate insiders with significant SEC Form 4 track records on InsiderAlpha:
Frequently Asked Questions
Who is Marcia Belvin?
Marcia Belvin is a corporate insider, tracked as SVP, Chief Scientific Officer of CytomX Therapeutics, Inc. (CTMX). InsiderAlpha holds 3 primary Form 4 filings for them, the earliest from 2025, updated as new SEC EDGAR filings are processed.
When did Marcia Belvin last file a Form 4?
The most recent primary Form 4 on record is dated 19 March 2026, one of 3 filings going back to 2025.
Has Marcia Belvin been buying or selling stock?
Recorded transactions: 0 open-market purchases and 1 open-market sale ($202K) across all tracked filings.
Where can I see all of Marcia Belvin's SEC filings?
All Form 4 filings, transaction values, and 10b5-1 plan flags are listed on this page and updated in real time as new SEC EDGAR filings are processed.
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