BLLN SEC Filing News — BillionToOne, Inc.

Latest SEC filings for BillionToOne, Inc. (BLLN) explained in plain English. Covers insider buying and selling (Form 4), proposed insider sales (Form 144), material company events (8-K), and quarterly & annual reports (10-Q / 10-K). StrongBuyAnalytics provides navigation and brief excerpts or summaries; original filings remain at the SEC/source links and were authored by their filers, not StrongBuyAnalytics. Filing dates shown are source dates. Coverage and detection can be delayed or incomplete because of SEC availability, amendments, parsing, caching, or outages. Latest source filing date shown: 2026-10-16.

BillionToOne, Inc., a precision diagnostics company, quantifies biology to create molecular diagnostics. The company provides molecular counting platform, which is designed to detect and measure DNA molecules at the single-count level to help enhance disease detection. It also offers UNITY Complete, a non-invasive prenatal screen that assesses fetal risk for aneuploidies, recessive conditions, and fetal antigens from a maternal blood draw; Northstar Select, a liquid biopsy test that provides a l…
Sector: Healthcare Industry: Diagnostics & Research Market Cap: $4.8B CIK: 2070849
20
Total Filings
0
Bullish Classifications
7
Bearish Classifications
8
Insider Transactions
0
Material Events (8-K)
0
Periodic Reports
Rule-based classifications for BLLN currently lean bearish. Of the 20 filing records displayed, 7 carry bearish classifications (such as insider sales or negative 8-K disclosures) versus 0 bullish. This does not necessarily signal fundamental deterioration — insiders sell for many reasons — but it is worth monitoring alongside the company's core financial metrics.
BLLN Filing Activity Snapshot 2026-09-24 — 2026-10-16
Insider Transactions (Form 4)
0 buys vs 7 sells
Net insider selling in this period — insiders sell for many reasons beyond conviction.
Largest Form 144 Filing
$2.16M
Tsao David · 2026-10-05
20,000 shares · Form 144
Form 144 Notices
12
Proposed insider sales filed — Form 144 is a notice of intent, not a confirmed transaction. Actual sales are confirmed via Form 4.
Insider Transactions 8 · Forms 3, 4 and 5

A Form 4 is filed within two business days of a company insider — an officer, a director, or a holder of more than ten percent of the stock — changing their position in the shares. All 8 filings in this group are Form 4s for BillionToOne, Inc.

The difficulty with reading these filings as a group is that a single form type covers transactions that mean entirely different things. An executive spending their own money to buy stock and an executive having shares withheld to pay tax on a vesting grant both appear as a Form 4. Every filing below is therefore tagged with the nature of the underlying transaction, taken from the transaction code reported on the form itself.

Across the 8 insider filings shown, the breakdown is 7 open-market sale and 1 option exercise. 7 of them involved a discretionary open-market trade; the rest are compensation and administrative mechanics.

What each transaction type means

Open-market sale ×7
The insider sold shares on the open market. Sales may be discretionary or executed automatically under a pre-arranged Rule 10b5-1 trading plan, and a Form 4 does not always make clear which applies.
Option exercise ×1
The insider converted options into shares. The exercise price was fixed when the options were granted, so the timing usually tracks an expiry schedule.
Form 4 Open-market sale Insider Selling 2026-10-16

BLLN insider Atay Oguzhan (Director, Chairman and CEO) sold 11,000 shares (~$1.09M)

Atay Oguzhan, listed as Director, Chairman and CEO at BillionToOne, Inc., reported an open-market sale of 11,000 BLLN shares in a Form 4 filing. This is a confirmed insider sale, not just a proposed sale notice.

The insider sold shares on the open market. Sales may be discretionary or executed automatically under a pre-arranged Rule 10b5-1 trading plan, and a Form 4 does not always make clear which applies.

Transactions reported on this filing
Code Nature Shares Price Value
M Option exercise 3,183 $2.80 $8.9K
S Open-market sale 3,083 $98.32 $303.1K
S Open-market sale 100 $99.00 $9.9K
M Option exercise 5,150 $2.80 $14.4K
S Open-market sale 900 $98.43 $88.6K
S Open-market sale 1,861 $99.84 $185.8K
S Open-market sale 1,276 $100.60 $128.4K
S Open-market sale 980 $101.79 $99.8K
S Open-market sale 133 $102.78 $13.7K
S Open-market sale 2,667 $98.00 $261.4K
M Option exercise derivative · Stock Option (right to buy) 3,183 $2.80 $8.9K
M Option exercise derivative · Stock Option (right to buy) 5,150 $2.80 $14.4K
Filing: Form 4 (Insider Transaction) Insider: Atay Oguzhan (Director, Chairman and CEO) Shares: 11,000 Est. Value: $1.09M
View on SEC EDGAR → Open Filing Document →
Form 4 Open-market sale Insider Selling 2026-10-14

BLLN insider Atay Oguzhan (Director, Chairman and CEO) sold 19,334 shares (~$1.82M)

Atay Oguzhan, listed as Director, Chairman and CEO at BillionToOne, Inc., reported an open-market sale of 19,334 BLLN shares in a Form 4 filing. This is a confirmed insider sale, not just a proposed sale notice.

The insider sold shares on the open market. Sales may be discretionary or executed automatically under a pre-arranged Rule 10b5-1 trading plan, and a Form 4 does not always make clear which applies.

Transactions reported on this filing
Code Nature Shares Price Value
M Option exercise 16,667 $2.80 $46.7K
S Open-market sale 1,961 $91.57 $179.6K
S Open-market sale 2,553 $93.05 $237.5K
S Open-market sale 6,763 $93.65 $633.3K
S Open-market sale 3,869 $94.61 $366.1K
S Open-market sale 1,521 $96.39 $146.6K
S Open-market sale 2,667 $97.61 $260.3K
M Option exercise derivative · Stock Option (right to buy) 16,667 $2.80 $46.7K
Filing: Form 4 (Insider Transaction) Insider: Atay Oguzhan (Director, Chairman and CEO) Shares: 19,334 Est. Value: $1.82M
View on SEC EDGAR → Open Filing Document →
Form 4 Option exercise Tax / Compensation Filing 2026-10-13

BLLN insider Form 4 filed for equity award, exercise, or tax withholding

Lynch Thomas P. (See Remarks) filed a Form 4 covering compensation-related activity such as stock awards, option exercises, conversions, or tax withholding. These filings are usually neutral.

The insider converted options into shares. The exercise price was fixed when the options were granted, so the timing usually tracks an expiry schedule.

Transactions reported on this filing
Code Nature Shares Price Value
M Option exercise 8,000 $8.65 $69.2K
M Option exercise derivative · Stock Option (right to buy) 8,000 $8.65 $69.2K
Filing: Form 4 (Insider Transaction) Insider: Lynch Thomas P. (See Remarks) Shares: 8,000
View on SEC EDGAR → Open Filing Document →
Form 4 Open-market sale Insider Selling 2026-10-07

BLLN insider ten Bosch John Roderick (SVP of Laboratory Operations) sold 2,834 shares (~$298.0K)

ten Bosch John Roderick, listed as SVP of Laboratory Operations at BillionToOne, Inc., reported an open-market sale of 2,834 BLLN shares in a Form 4 filing. This is a confirmed insider sale, not just a proposed sale notice.

The insider sold shares on the open market. Sales may be discretionary or executed automatically under a pre-arranged Rule 10b5-1 trading plan, and a Form 4 does not always make clear which applies.

Transactions reported on this filing
Code Nature Shares Price Value
S Open-market sale 1,417 $105.15 $149.0K
S Open-market sale 1,417 $105.15 $149.0K
Filing: Form 4 (Insider Transaction) Insider: ten Bosch John Roderick (SVP of Laboratory Operations) Shares: 2,834 Est. Value: $298.0K
View on SEC EDGAR → Open Filing Document →
Form 4 Open-market sale Insider Selling 2026-10-07

BLLN insider Tsao David (Director, Chief Technology Officer) sold 20,000 shares (~$2.16M)

Tsao David, listed as Director, Chief Technology Officer at BillionToOne, Inc., reported an open-market sale of 20,000 BLLN shares in a Form 4 filing. This is a confirmed insider sale, not just a proposed sale notice.

The insider sold shares on the open market. Sales may be discretionary or executed automatically under a pre-arranged Rule 10b5-1 trading plan, and a Form 4 does not always make clear which applies.

Transactions reported on this filing
Code Nature Shares Price Value
M Option exercise 10,000 $2.80 $28.0K
M Option exercise 10,000 $2.80 $28.0K
S Open-market sale 866 $105.90 $91.7K
S Open-market sale 1,909 $107.19 $204.6K
S Open-market sale 4,284 $108.39 $464.4K
S Open-market sale 2,921 $109.00 $318.4K
S Open-market sale 20 $110.08 $2.2K
S Open-market sale 555 $105.56 $58.6K
S Open-market sale 400 $106.10 $42.4K
S Open-market sale 2,200 $107.47 $236.4K
S Open-market sale 4,916 $108.53 $533.6K
S Open-market sale 1,829 $109.14 $199.6K
S Open-market sale 100 $110.09 $11.0K
M Option exercise derivative · Stock Option (right to buy) 10,000 $2.80 $28.0K
M Option exercise derivative · Stock Option (right to buy) 10,000 $2.80 $28.0K
Filing: Form 4 (Insider Transaction) Insider: Tsao David (Director, Chief Technology Officer) Shares: 20,000 Est. Value: $2.16M
View on SEC EDGAR → Open Filing Document →
Form 4 Open-market sale Insider Selling 2026-09-30

BLLN insider Atay Oguzhan (Director, Chairman and CEO) sold 10,999 shares (~$1.33M)

Atay Oguzhan, listed as Director, Chairman and CEO at BillionToOne, Inc., reported an open-market sale of 10,999 BLLN shares in a Form 4 filing. This is a confirmed insider sale, not just a proposed sale notice.

The insider sold shares on the open market. Sales may be discretionary or executed automatically under a pre-arranged Rule 10b5-1 trading plan, and a Form 4 does not always make clear which applies.

Transactions reported on this filing
Code Nature Shares Price Value
M Option exercise 8,333 $2.80 $23.3K
S Open-market sale 8,333 $120.64 $1.01M
S Open-market sale 2,666 $120.64 $321.6K
M Option exercise derivative · Stock Option (right to buy) 8,333 $2.80 $23.3K
Filing: Form 4 (Insider Transaction) Insider: Atay Oguzhan (Director, Chairman and CEO) Shares: 10,999 Est. Value: $1.33M
View on SEC EDGAR → Open Filing Document →
Form 4 Open-market sale Insider Selling 2026-09-28

BLLN insider Tsao David (Director, Chief Technology Officer) sold 3,333 shares (~$416.6K)

Tsao David, listed as Director, Chief Technology Officer at BillionToOne, Inc., reported an open-market sale of 3,333 BLLN shares in a Form 4 filing. This is a confirmed insider sale, not just a proposed sale notice.

The insider sold shares on the open market. Sales may be discretionary or executed automatically under a pre-arranged Rule 10b5-1 trading plan, and a Form 4 does not always make clear which applies.

Transactions reported on this filing
Code Nature Shares Price Value
M Option exercise 3,333 $2.80 $9.3K
S Open-market sale 3,333 $125.00 $416.6K
M Option exercise derivative · Stock Option (right to buy) 3,333 $2.80 $9.3K
Filing: Form 4 (Insider Transaction) Insider: Tsao David (Director, Chief Technology Officer) Shares: 3,333 Est. Value: $416.6K
View on SEC EDGAR → Open Filing Document →
Form 4 Open-market sale Insider Selling 2026-09-28

BLLN insider ten Bosch John Roderick (SVP of Laboratory Operations) sold 1,416 shares (~$169.9K)

ten Bosch John Roderick, listed as SVP of Laboratory Operations at BillionToOne, Inc., reported an open-market sale of 1,416 BLLN shares in a Form 4 filing. This is a confirmed insider sale, not just a proposed sale notice.

The insider sold shares on the open market. Sales may be discretionary or executed automatically under a pre-arranged Rule 10b5-1 trading plan, and a Form 4 does not always make clear which applies.

Transactions reported on this filing
Code Nature Shares Price Value
S Open-market sale 1,416 $120.00 $169.9K
Filing: Form 4 (Insider Transaction) Insider: ten Bosch John Roderick (SVP of Laboratory Operations) Shares: 1,416 Est. Value: $169.9K
View on SEC EDGAR → Open Filing Document →
Proposed Insider Sales 12 · Form 144

A Form 144 is a notice of intent to sell restricted or control securities. It is not a record that anything was sold. BillionToOne, Inc. has 12 such notices in this period.

The distinction matters because a Form 144 is frequently reported as though it were a completed insider sale. The filer may sell all of the shares covered, some of them, or none at all, and there is no obligation to update the notice either way. A sale that is actually executed by an officer or director shows up separately on a Form 4, which is the filing to check before treating a proposed sale as a real one.

Form 144 Proposed Insider Sale 2026-10-15

BLLN Form 144 filed for proposed insider sale by Atay Oguzhan (5,150 shares) ~$516.2K

Atay Oguzhan filed a Form 144 with the SEC indicating intent to sell BLLN (BillionToOne, Inc.) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: Atay Oguzhan Shares: 5,150 Est. Value: $516.2K
View on SEC EDGAR → Open Filing Document →
Form 144 Proposed Insider Sale 2026-10-14

BLLN Form 144 filed for proposed insider sale by Atay Oguzhan (3,183 shares) ~$313.0K

Atay Oguzhan filed a Form 144 with the SEC indicating intent to sell BLLN (BillionToOne, Inc.) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: Atay Oguzhan Shares: 3,183 Est. Value: $313.0K
View on SEC EDGAR → Open Filing Document →
Form 144 Proposed Insider Sale 2026-10-14

BLLN Form 144 filed for proposed insider sale by Atay Oguzhan (2,667 shares) ~$261.4K

Atay Oguzhan filed a Form 144 with the SEC indicating intent to sell BLLN (BillionToOne, Inc.) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: Atay Oguzhan Shares: 2,667 Est. Value: $261.4K
View on SEC EDGAR → Open Filing Document →
Form 144 Proposed Insider Sale 2026-10-13

BLLN Form 144 filed for proposed insider sale by Atay Oguzhan (2,667 shares) ~$260.3K

Atay Oguzhan filed a Form 144 with the SEC indicating intent to sell BLLN (BillionToOne, Inc.) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: Atay Oguzhan Shares: 2,667 Est. Value: $260.3K
View on SEC EDGAR → Open Filing Document →
Form 144 Proposed Insider Sale 2026-10-13

BLLN Form 144 filed for proposed insider sale by Atay Oguzhan (16,667 shares) ~$1.56M

Atay Oguzhan filed a Form 144 with the SEC indicating intent to sell BLLN (BillionToOne, Inc.) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: Atay Oguzhan Shares: 16,667 Est. Value: $1.56M
View on SEC EDGAR → Open Filing Document →
Form 144 Proposed Insider Sale 2026-10-05

BLLN Form 144 filed for proposed insider sale by Tsao David (20,000 shares) ~$2.16M

Tsao David filed a Form 144 with the SEC indicating intent to sell BLLN (BillionToOne, Inc.) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: Tsao David Shares: 20,000 Est. Value: $2.16M
View on SEC EDGAR → Open Filing Document →
Form 144 Proposed Insider Sale 2026-10-05

BLLN Form 144 filed for proposed insider sale by ten Bosch John Roderick (2,834 shares) ~$298.0K

ten Bosch John Roderick filed a Form 144 with the SEC indicating intent to sell BLLN (BillionToOne, Inc.) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: ten Bosch John Roderick Shares: 2,834 Est. Value: $298.0K
View on SEC EDGAR → Open Filing Document →
Form 144 Proposed Insider Sale 2026-10-05

BLLN Form 144 filed for proposed insider sale by Tsao David (1,750 shares) ~$184.0K

Tsao David filed a Form 144 with the SEC indicating intent to sell BLLN (BillionToOne, Inc.) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: Tsao David Shares: 1,750 Est. Value: $184.0K
View on SEC EDGAR → Open Filing Document →
Form 144 Proposed Insider Sale 2026-09-28

BLLN Form 144 filed for proposed insider sale by Atay Oguzhan (2,666 shares) ~$321.6K

Atay Oguzhan filed a Form 144 with the SEC indicating intent to sell BLLN (BillionToOne, Inc.) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: Atay Oguzhan Shares: 2,666 Est. Value: $321.6K
View on SEC EDGAR → Open Filing Document →
Form 144 Proposed Insider Sale 2026-09-28

BLLN Form 144 filed for proposed insider sale by Atay Oguzhan (8,333 shares) ~$1.01M

Atay Oguzhan filed a Form 144 with the SEC indicating intent to sell BLLN (BillionToOne, Inc.) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: Atay Oguzhan Shares: 8,333 Est. Value: $1.01M
View on SEC EDGAR → Open Filing Document →
Form 144 Proposed Insider Sale 2026-09-24

BLLN Form 144 filed for proposed insider sale by Tsao David (3,333 shares) ~$416.6K

Tsao David filed a Form 144 with the SEC indicating intent to sell BLLN (BillionToOne, Inc.) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: Tsao David Shares: 3,333 Est. Value: $416.6K
View on SEC EDGAR → Open Filing Document →
Form 144 Proposed Insider Sale 2026-09-24

BLLN Form 144 filed for proposed insider sale by ten Bosch John Roderick (1,416 shares) ~$169.9K

ten Bosch John Roderick filed a Form 144 with the SEC indicating intent to sell BLLN (BillionToOne, Inc.) shares. Form 144 reflects a proposed sale, not a completed transaction. The actual execution, if any, would typically appear later in a Form 4.

Filing: Form 144 (Proposed Sale Notice) Insider: ten Bosch John Roderick Shares: 1,416 Est. Value: $169.9K
View on SEC EDGAR → Open Filing Document →

How we classify BillionToOne, Inc.'s filings

Straight from EDGAR

Each displayed record links to an original source document. StrongBuyAnalytics provides navigation and brief excerpts or summaries, not the filing itself. Parsing may omit context or contain errors, so read the original document in full.

Transaction codes, not guesswork

The nature shown on each insider filing comes from the transaction code the filer entered on the form itself — P for an open-market purchase, A for a compensation award, F for shares withheld to pay tax, M for an option exercise. Where one filing contains several codes, the transaction table lists them line by line.

Why the distinction matters

Insider activity is routinely summarised as buying or selling, which flattens together decisions that mean very different things. Shares withheld for tax on a vesting grant are an automatic administrative step; shares bought on the open market are someone committing their own money at the current price.

What this page does not tell you

A filing records what happened, not why. Form 4 does not always disclose whether a sale was executed under a pre-arranged Rule 10b5-1 plan, and no single filing is a basis for a decision on BLLN. Read these alongside the fundamentals rather than in isolation.

Frequently Asked Questions — BLLN SEC Filings

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Publisher, sources & limitations — September 15, 2026. StrongBuyAnalytics provides navigation and brief excerpts or summaries for educational use. Original filings remain at SEC EDGAR or other displayed source links; StrongBuyAnalytics does not author them. Filing dates are source dates, not publication dates for this page. Coverage can be delayed, incomplete, amended, or unavailable because of SEC/source availability, parsing, caching, or outages. Verify every material statement in the original filing.
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