Reporting owner · CIK 0002087127
Tsao David
SEC Form 4 history across 1 companies, 30 transactions and 5 filings.
CTOChief Technology OfficerBillionToOne, Inc.
Open-market transaction mix0% buys0 buys · 15 sales
Available history · Aug 25, 2026 – Oct 05, 2026
Latest insider transactions
Form 4 filings from available history.| Company | Insider | Activity | Disclosed value | Filed (ET) |
|---|---|---|---|---|
BLLNBillionToOne, Inc. | Tsao DavidCTO | S · sale10b5-1 detectedSEC filing ↗ | -$1.00MView disclosure → | |
BLLNBillionToOne, Inc. | Tsao DavidCTO | S · sale10b5-1 detectedSEC filing ↗ | -$975kView disclosure → | |
BLLNBillionToOne, Inc. | Tsao DavidCTO | M · exercise10b5-1 detectedSEC filing ↗ | $28.0kView disclosure → | |
BLLNBillionToOne, Inc. | Tsao DavidCTO | M · exercise10b5-1 detectedSEC filing ↗ | $28.0kView disclosure → | |
BLLNBillionToOne, Inc. | Tsao DavidCTO | C · unknownDerivative securitySEC filing ↗ | $0View disclosure → | |
BLLNBillionToOne, Inc. | Tsao DavidCTO | G · giftSEC filing ↗ | $0View disclosure → | |
BLLNBillionToOne, Inc. | Tsao DavidCTO | C · unknownSEC filing ↗ | $0View disclosure → | |
BLLNBillionToOne, Inc. | Tsao DavidCTO | M · exercise10b5-1 detectedDerivative securitySEC filing ↗ | -$28.0kView disclosure → | |
BLLNBillionToOne, Inc. | Tsao DavidCTO | S · sale10b5-1 detectedSEC filing ↗ | -$1.00MView disclosure → | |
BLLNBillionToOne, Inc. | Tsao DavidCTO | M · exercise10b5-1 detectedSEC filing ↗ | $28.0kView disclosure → |
Latest Form 4 facts
Quick context from source filings
Latest open-market transaction
sale at BillionToOne, Inc. on Oct 05, 2026 valued at $11,009.
Review SEC filingLatest buy
No open-market insider purchase is available.
Monthly open-market activity
Last 3 reported months · purchases and sales
View exact monthly values
| Month | Purchases | Sales | Buy value | Sale value | Net value |
|---|---|---|---|---|---|
| Aug 2026 | 0 | 1 | $0.00 | $1,000,000.00 | -$1,000,000.00 |
| Sep 2026 | 0 | 3 | $0.00 | $2,392,025.00 | -$2,392,025.00 |
| Oct 2026 | 0 | 11 | $0.00 | $2,162,950.40 | -$2,162,950.40 |
Net value is disclosed purchases minus sales, not profit. A dash means the value is unavailable.
Ownership and transaction size
Ownership and ticket size
Average P/S size$370.3K
Median P/S size$236.4K
Direct30
Indirect0
Oct 05, 2026exercise
Filing-only signals
Deterministic matches in this insider's history
Associated companies
Companies in the disclosed reporting history
Open-market buy performance
90-day forward return on this insider's open-market purchases
No open-market purchases in available history
A 90-day purchase return requires an open-market buy. No eligible purchases are recorded in this history.
Disclosed ownership
How reported shareholdings evolved
Non-derivative shares held after reported transactions—not stock prices or a complete portfolio.
23 observations · Aug 25, 2026 – Oct 5, 2026. Window ends at the latest available report, not today.
Selected observation · Oct 5, 20261,000 shares reported
Inspect transaction View exact observations and source transactions
| Transaction date | Shares held after | Filed | Source |
|---|---|---|---|
| Aug 25, 2026 | 11,000 | Aug 28, 2026 | View transaction |
| Aug 25, 2026 | 1,000 | Aug 28, 2026 | View transaction |
| Sep 3, 2026 | 21,000 | Sep 9, 2026 | View transaction |
| Sep 8, 2026 | 1,000 | Sep 9, 2026 | View transaction |
| Sep 9, 2026 | 11,000 | Sep 11, 2026 | View transaction |
| Sep 9, 2026 | 21,000 | Sep 11, 2026 | View transaction |
| Sep 9, 2026 | 11,000 | Sep 11, 2026 | View transaction |
| Sep 9, 2026 | 1,000 | Sep 11, 2026 | View transaction |
| Sep 24, 2026 | 4,333 | Sep 28, 2026 | View transaction |
| Sep 24, 2026 | 1,000 | Sep 28, 2026 | View transaction |
| Oct 5, 2026 | 11,000 | Oct 7, 2026 | View transaction |
| Oct 5, 2026 | 21,000 | Oct 7, 2026 | View transaction |
| Oct 5, 2026 | 20,134 | Oct 7, 2026 | View transaction |
| Oct 5, 2026 | 18,225 | Oct 7, 2026 | View transaction |
| Oct 5, 2026 | 13,941 | Oct 7, 2026 | View transaction |
| Oct 5, 2026 | 11,020 | Oct 7, 2026 | View transaction |
| Oct 5, 2026 | 11,000 | Oct 7, 2026 | View transaction |
| Oct 5, 2026 | 10,445 | Oct 7, 2026 | View transaction |
| Oct 5, 2026 | 10,045 | Oct 7, 2026 | View transaction |
| Oct 5, 2026 | 7,845 | Oct 7, 2026 | View transaction |
| Oct 5, 2026 | 2,929 | Oct 7, 2026 | View transaction |
| Oct 5, 2026 | 1,100 | Oct 7, 2026 | View transaction |
| Oct 5, 2026 | 1,000 | Oct 7, 2026 | View transaction |
Securities and direct/indirect ownership contexts are kept separate and never summed. Joint filings may associate the same disclosed row with multiple owners. Unknown values are omitted, not treated as zero. Lines connect observations for readability; they do not establish holdings between filings, cost basis, or current ownership. Amendments and stock splits require reviewing the source.
Tsao David Insider Activity FAQ
SEC Form 4 context
Who is Tsao David?
Tsao David is a reporting owner in SEC Form 4 filings with reporting owner CIK 0002087127.
Which companies has Tsao David reported transactions for?
BillionToOne, Inc.
When was Tsao David's latest insider buy?
No open-market insider purchase is available for this period.
When was Tsao David's latest insider sale?
sale at BillionToOne, Inc. on Oct 05, 2026 valued at $11,009.
Where can I see the original SEC filings?
Each transaction row links directly to the source SEC filing so the reported Form 4 details can be reviewed.
Are performance metrics included?
The profile shows average and median 90-day stock returns after open-market purchases when price coverage is available. These are unadjusted stock returns, not realized trading gains. Win rates, benchmark-adjusted returns and conviction scores are not calculated.