SEC Form 4
MBX Biosciences, Inc. (MBX) insider trading
In the 12 months to Nov 12, 2026, one MBX insider reported open-market sales of $2.7M across 1 filing; one president & CEO bought $525.7K.
Latest filing · Last 12 months · Source: SEC EDGAR · How we count
- Open-market sales
- $2.7M
- 1 filing · 1 insider
- Open-market purchases
- $525.7K
- 1 filing · P. Kent Hawryluk, President & CEO
- Pre-arranged sales (10b5-1)
- 1 of 1
- All $2.7M sold was pre-arranged
Who traded MBX, and when
- Purchase
- Sale
- Sale, pre-arranged (10b5-1)
MBX daily close from Nov 12, 2025 to Nov 12, 2026, between $24.07 and $70.70, last $54.86. 1 sale and 1 purchase filings by 2 insiders, marked at their filing dates. Salomon Azoulay, Chief Medical Officer: sold $2.7M across 1 filing, first filed May 11, 2026, last May 11, 2026. P. Kent Hawryluk, President & CEO: bought $525.7K across 1 filing, first filed Mar 16, 2026, last Mar 16, 2026.
Largest mark · tap a row for others
Salomon Azoulay · Chief Medical Officer
Sale $2,685,515
70,003 shares at $38.36 avg
Filed May 11, 2026 · traded May 8
Pre-arranged (10b5-1) · close on filing date $40.08
Salomon Azoulay · Chief Medical Officer
Chief Medical Officer
$2.7M soldP. Kent Hawryluk · President & CEO
President & CEO
$525.7K boughtOpen-market trades
2 filings in the last 12 months| Insider | Role | Sold | Bought | Filings | Pre-arranged (10b5-1) | Last filed |
|---|---|---|---|---|---|---|
| Salomon Azoulay | Chief Medical Officer | $2.7M | — | 1 | 100% of sales | |
| P. Kent Hawryluk | President & CEO | — | $525.7K | 1 | — |
| Filed | Insider | Type | Shares | Avg price | Value | Held after | Source |
|---|---|---|---|---|---|---|---|
traded | Salomon Azoulay Chief Medical Officer | SalePre-arranged (10b5-1) | 70,003 | $38.36 | $2.7M | 14,769 | |
traded | P. Kent Hawryluk President & CEO | Purchase | 18,500 | $28.41 | $525.7K | 486,777 |
GET /stocks/filings/vX/form-4?tickers=MBX&filing_date.gte=2025-11-12&sort=filing_date.desc&limit=500{
"status": "OK",
"results": [
{
"tickers": [
"MBX"
],
"issuer_cik": "0001776111",
"owner_cik": "0002030246",
"accession_number": "0001193125-26-216704",
"form_type": "4",
"filing_date": "2026-05-11",
"period_of_report": "2026-05-08",
"issuer_name": "MBX Biosciences, Inc.",
"issuer_trading_symbol": "MBX",
"owner_name": "Azoulay Salomon",
"is_director": false,
"is_officer": true,
"is_ten_percent_owner": false,
"is_other": false,
"officer_title": "Chief Medical Officer",
"security_type": "non_derivative",
"record_type": "transaction",
"security_title": "Common Stock",
"transaction_timeliness": "O",
"aff_10b5_one": true,
"transaction_date": "2026-05-08",
"transaction_code": "S",
"equity_swap_involved": false,
"transaction_shares": 15003,
"transaction_price_per_share": 38.3,
"transaction_acquired_disposed": "D",
"shares_owned_following_transaction": 14769,
"transaction_value": 574614.8999999999,
"direct_or_indirect": "D",
"footnotes": [
{
"id": "F1",
"description": "The sales reported on this Form 4 represent the exercise and sale of common stock options by the reporting person pursuant to an approved Rule 10b5-1 trading plan adopted on January 27, 2026."
},
{
"id": "F3",
"description": "The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $35.00 to $41.26, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote."
}
]
},
{
"tickers": [
"MBX"
],
"issuer_cik": "0001776111",
"owner_cik": "0002030246",
"accession_number": "0001193125-26-216704",
"form_type": "4",
"filing_date": "2026-05-11",
"period_of_report": "2026-05-08",
"issuer_name": "MBX Biosciences, Inc.",
"issuer_trading_symbol": "MBX",
"owner_name": "Azoulay Salomon",
"is_director": false,
"is_officer": true,
"is_ten_percent_owner": false,
"is_other": false,
"officer_title": "Chief Medical Officer",
"security_type": "non_derivative",
"record_type": "transaction",
"security_title": "Common Stock",
"transaction_timeliness": "O",
"aff_10b5_one": true,
"transaction_date": "2026-05-08",
"transaction_code": "S",
"equity_swap_involved": false,
"transaction_shares": 55000,
"transaction_price_per_share": 38.38,
"transaction_acquired_disposed": "D",
"shares_owned_following_transaction": 14769,
"transaction_value": 2110900,
"direct_or_indirect": "D",
"footnotes": [
{
"id": "F1",
"description": "The sales reported on this Form 4 represent the exercise and sale of common stock options by the reporting person pursuant to an approved Rule 10b5-1 trading plan adopted on January 27, 2026."
},
{
"id": "F2",
"description": "The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $35.00 to $41.26, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote."
}
]
}
]
}
// trimmed to 2 resultsThe response includes every Form 4 record; this page keeps open-market purchases and sales on common stock and removes duplicate joint-filer rows.
Other insider activity (not market trades) · 13 records
- Option exercises3 records
- Tax withholding (sold to cover)4 records
- Grants and awards6 records
Reported on Form 4 but not purchases or sales in the market, so not counted in the totals above.
How to read this page
- Open-market purchase or sale
- A buy or sell of the company's stock at market price. Grants, option exercises, shares withheld for tax, gifts and employee stock plan purchases are listed separately and not counted.
- Pre-arranged (10b5-1)
- The insider marked the filing as made under a trading plan set up in advance (SEC Rule 10b5-1). The mark covers the whole filing, and an unmarked filing may still be under a plan.
- Filing date
- Insiders have two business days to report a trade. Totals and the chart use the filing date, when the trade became public.
Frequently asked questions
Has MBX Biosciences, Inc.'s CEO sold stock?
No. Steven L. Hoerter and P. Kent Hawryluk (CEOs) made no open-market sales filed as CEO in the last 12 months.
How current is MBX’s insider data?
These are MBX Form 4 filings from the last year, refreshed daily. The Massive Form 4 API has the full, continuously updated record.
What counts as an open-market buy or sell?
Only purchases and sales at the market price. Option exercises, grants, gifts, and shares withheld for taxes are reported on Form 4 but are left out of the buy and sell totals.
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Track MBX insider trades with your agent
This page joins two Massive endpoints: Form 4 filings and daily prices. Ask an agent to watch for new filings:
Using the Massive API (massive.com/docs/llms.txt), check Form 4 filings for MBX every day with transaction_code=P and tell me when an insider files an open-market purchase, with their role, shares, price and the filing link.
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