Insiders who reported open-market trades in the last 12 months at the companies David Tsao 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.
Oguzhan Atay - $27.17M in BLLN purchases and sales in the last 12 months
Thomas P. Lynch - $5.88M in BLLN purchases and sales in the last 12 months
Nancy Joann Johnson - $3.74M in BLLN purchases and sales in the last 12 months
David Tsao is a corporate insider, tracked as Chief Technology Officer, Director of BillionToOne, Inc. (BLLN). InsiderAlpha holds 9 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 David Tsao submitted recently?
6 primary Form 4 filings in the last 90 days, covering 1 company.
Has David Tsao been buying or selling stock?
Recorded transactions: 1 open-market purchase ($60K) and 37 open-market sales ($11.03M) across all tracked filings.
David Tsao is Chief Technology Officer, Director of BillionToOne, Inc. (BLLN). 9 SEC Form 4 filings on record going back to 2025, most recently on 7 October 2026. Most recent open-market trade: sold $11K of BLLN on 7 October 2026. Lifetime open-market purchases: $60K. Lifetime open-market sales: $11.03M.
Recent transactions
20
The latest 20 SEC Form 4 transactions reported by David Tsao.
InsiderAlpha's records for David Tsao go back to 2025: 9 primary Form 4 filings, an average of 4.5 per year. The typical open-market purchase is $60K (1 buy totaling $60K). The largest single buy on record is $60K of BLLN in 2025. Sales side: 37 recorded sales totaling $11.03M, so the filing history runs sell-heavy by dollar value. 59 recorded transactions carry a Rule 10b5-1 plan flag. This identifies the marked transactions as reported under a trading plan; it does not establish the plan status of unmarked transactions.
