Summary
Updated Aug 30, 2026
William Jl Rieflin files SEC Form 4 reports at Lyell Immunopharma, Inc. (LYEL). 2 SEC Form 4 filings on record going back to 2025, most recently on 12 June 2026.
Trading Pattern
InsiderAlpha's records for William Jl Rieflin go back to 2025: 2 primary Form 4 filings, an average of 1.0 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 William Jl Rieflin 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
- ARCH Venture Partners IX, LLC - $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
More Notable Insiders
Other corporate insiders with significant SEC Form 4 track records on InsiderAlpha:
Frequently Asked Questions
Who is William Jl Rieflin?
William Jl Rieflin is a corporate insider of Lyell Immunopharma, Inc. (LYEL). InsiderAlpha holds 2 primary Form 4 filings for them, the earliest from 2025, updated as new SEC EDGAR filings are processed.
How many SEC Form 4 filings has William Jl Rieflin submitted recently?
1 primary Form 4 filing in the last 90 days, covering 1 company.
Where can I see all of William Jl Rieflin'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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