Summary
Updated Aug 31, 2026
Heather L. Mason is Director of Immatics N.V. (IMTX). 5 SEC Form 4 filings on record going back to 2024, most recently on 18 June 2026. Most recent open-market trade: bought $60K of ASRT on 19 November 2024. Lifetime open-market purchases: $60K.
Recent Transactions
6Every recent SEC Form 4 transaction Heather L. Mason has reported, most recent first.
Trading Pattern
InsiderAlpha's records for Heather L. Mason go back to 2024: 5 primary Form 4 filings, an average of 1.7 per year. The typical open-market purchase is $60K (1 buy totaling $60K). The largest single buy on record is $60K of ASRT in 2024. 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 Heather L. Mason 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.
- PERCEPTIVE ADVISORS LLC - $7.50M of IMTX open-market activity in the last 12 months
- David Matthew Stark - $7K of ASRT 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 Heather L. Mason?
Heather L. Mason is a corporate insider, tracked as Director of Immatics N.V. (IMTX). InsiderAlpha holds 5 primary Form 4 filings for them, the earliest from 2024, updated as new SEC EDGAR filings are processed.
How many SEC Form 4 filings has Heather L. Mason submitted recently?
2 primary Form 4 filings in the last 90 days, covering 2 companies.
Has Heather L. Mason been buying or selling stock?
Recorded transactions: 1 open-market purchase ($60K) and 0 open-market sales across all tracked filings.
Where can I see all of Heather L. Mason'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.
Learn More
Follow Heather L. Mason and every insider like them
A free account opens the full scored daily plan and every past day, a watchlist for any ticker, and 3 months of price history on every company page. No card.
Free plan available · Paid plans start with a 7-day free trial