Summary
Updated Aug 31, 2026
ARCH Venture Partners IX, LLC is 10% Owner of Lyell Immunopharma, Inc. (LYEL). 2 SEC Form 4 filings on record going back to 2025, most recently on 9 March 2026. Most recent open-market trade: bought $12.50M of LYEL on 9 March 2026. Lifetime open-market purchases: $12.50M.
Recent Transactions
1Every recent SEC Form 4 transaction ARCH Venture Partners IX, LLC has reported, most recent first.
Trading Pattern
InsiderAlpha's records for ARCH Venture Partners IX, LLC go back to 2025: 2 primary Form 4 filings, an average of 1.0 per year. The typical open-market purchase is $12.50M (1 buy totaling $12.50M). The largest single buy on record is $12.50M of LYEL in 2026. 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 ARCH Venture Partners IX, LLC 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.
- ARCH Venture Fund XIII, L.P. - $12.50M of LYEL open-market activity in the last 12 months
- Lynn Seely - $353K of LYEL open-market activity in the last 12 months
- Gary K. Lee - $72K of LYEL open-market activity in the last 12 months
- Stephen J. Hill - $51K of LYEL open-market activity in the last 12 months
- David Shook - $25K of LYEL open-market activity in the last 12 months
- Veronica Sanchez Bulis - $23K of LYEL 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
What is ARCH Venture Partners IX, LLC?
ARCH Venture Partners IX, LLC is an investment firm, tracked as 10% Owner of Lyell Immunopharma, Inc. (LYEL). InsiderAlpha holds 2 primary Form 4 filings for it, the earliest from 2025, updated as new SEC EDGAR filings are processed.
When did ARCH Venture Partners IX, LLC last file a Form 4?
The most recent primary Form 4 on record is dated 9 March 2026, one of 2 filings going back to 2025.
Has ARCH Venture Partners IX, LLC been buying or selling stock?
Recorded transactions: 1 open-market purchase ($12.50M) and 0 open-market sales across all tracked filings.
Where can I see all of ARCH Venture Partners IX, LLC'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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