SEC Form 4
TRex Bio, Inc. (TRXB) insider trading
In the 12 months to Oct 26, 2026, 3 TRXB insiders reported open-market purchases of $3.8M across 3 filings; no open-market sales were filed.
Latest filing · Last 12 months · Source: SEC EDGAR · How we count
- Open-market sales
- $0
- 0 filings · 0 insiders
- Open-market purchases
- $3.8M
- 3 filings
Who traded TRXB, and when
- Purchase
TRXB daily close from Oct 9, 2026 to Oct 26, 2026, between $13.50 and $15.50, last $13.81. 0 sale and 3 purchase filings by 3 insiders, marked at their filing dates. Alexandria Venture Investments, LLC, 10% owner: bought $2.5M across 1 filing, first filed Oct 15, 2026, last Oct 15, 2026. SVLSF VI, LLC, 10% owner: bought $1.3M across 1 filing, first filed Oct 13, 2026, last Oct 13, 2026. SV Life Sciences Fund VI (GP), L.P., 10% owner: bought $43.0K across 1 filing, first filed Oct 13, 2026, last Oct 13, 2026.
Largest mark · tap a row for others
Alexandria Venture Investments, LLC · 10% owner
Purchase $2,499,994
178,571 shares at $14.00 avg
Filed Oct 15, 2026 · traded Oct 13
Close on filing date $14.16
Alexandria Venture Investments, LLC · 10% owner
10% owner
$2.5M boughtSVLSF VI, LLC · 10% owner
10% owner
$1.3M boughtSV Life Sciences Fund VI (GP), L.P. · 10% owner
10% owner
$43.0K boughtOpen-market trades
3 filings in the last 12 months| Insider | Role | Sold | Bought | Filings | Pre-arranged (10b5-1) | Last filed |
|---|---|---|---|---|---|---|
| Alexandria Venture Investments, LLC | 10% owner | — | $2.5M | 1 | — | |
| SVLSF VI, LLC | 10% owner | — | $1.3M | 1 | — | |
| SV Life Sciences Fund VI (GP), L.P. | 10% owner | — | $43.0K | 1 | — |
| Filed | Insider | Type | Shares | Avg price | Value | Held after | Source |
|---|---|---|---|---|---|---|---|
traded | Alexandria Venture Investments, LLC 10% owner | Purchase | 178,571 | $14.00 | $2.5M | 1,346,501 | |
traded | SVLSF VI, LLC 10% owner | Purchase | 89,783 | $14.00 | $1.3M | 214,869 | |
traded | SV Life Sciences Fund VI (GP), L.P. 10% owner | Purchase | 3,074 | $14.00 | $43.0K | 7,356 |
GET /stocks/filings/vX/form-4?tickers=TRXB&filing_date.gte=2025-10-26&sort=filing_date.desc&limit=500{
"status": "OK",
"results": [
{
"tickers": [
"TRXB"
],
"issuer_cik": "0002139097",
"owner_cik": "0001722024",
"accession_number": "0001722024-26-000004",
"form_type": "4",
"filing_date": "2026-10-15",
"period_of_report": "2026-10-13",
"issuer_name": "TRex Bio, Inc.",
"issuer_trading_symbol": "TRXB",
"owner_name": "Alexandria Venture Investments, LLC",
"is_director": false,
"is_officer": false,
"is_ten_percent_owner": true,
"is_other": false,
"security_type": "non_derivative",
"record_type": "transaction",
"security_title": "Common Stock",
"transaction_timeliness": "O",
"aff_10b5_one": false,
"transaction_date": "2026-10-13",
"transaction_code": "P",
"equity_swap_involved": false,
"transaction_shares": 178571,
"transaction_price_per_share": 14,
"transaction_acquired_disposed": "A",
"shares_owned_following_transaction": 1346501,
"transaction_value": 2499994,
"not_subject_to_section_16": true,
"direct_or_indirect": "D"
},
{
"tickers": [
"TRXB"
],
"issuer_cik": "0002139097",
"owner_cik": "0001717728",
"accession_number": "0001829126-26-011084",
"form_type": "4",
"filing_date": "2026-10-13",
"period_of_report": "2026-10-08",
"issuer_name": "TRex Bio, Inc.",
"issuer_trading_symbol": "TRXB",
"owner_name": "SVLSF VI, LLC",
"is_director": false,
"is_officer": false,
"is_ten_percent_owner": true,
"is_other": false,
"security_type": "non_derivative",
"record_type": "transaction",
"security_title": "Common Stock",
"transaction_timeliness": "O",
"aff_10b5_one": false,
"transaction_date": "2026-10-08",
"transaction_code": "P",
"equity_swap_involved": false,
"transaction_shares": 89783,
"transaction_price_per_share": 14,
"transaction_acquired_disposed": "A",
"shares_owned_following_transaction": 214869,
"transaction_value": 1256962,
"not_subject_to_section_16": false,
"direct_or_indirect": "I",
"nature_of_ownership": "By SV Life Sciences Fund VI, L.P.",
"footnotes": [
{
"id": "F1",
"description": "The shares are held directly by SV Life Sciences Fund VI, L.P. (\"SV Fund VI\"). SV Life Sciences Fund VI (GP), L.P. (the \"GP LP\") is the general partner of SV Fund VI, and SVLSF VI, LLC (\"SVLSF\") is the general partner of GP LP. Investment and voting decisions of SV Fund VI are made by the investment committee of SVLSF. Each of GP LP and SVLSF disclaims beneficial ownership except to the extent of its pecuniary interest, and this report is not an admission of beneficial ownership for any other purpose."
},
{
"id": "F5",
"description": "Represents shares purchased by SV Fund VI in the issuer's initial public offering."
}
]
}
]
}
// 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) · 7 records
- Other7 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.
- Filing date
- Insiders have two business days to report a trade. Totals and the chart use the filing date, when the trade became public.
- Counted once
- When several owners (a fund and its partners, say) report the same trade, it's counted once. Corrected filings replace the originals.
Frequently asked questions
How current is TRXB’s insider data?
These are TRXB 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 TRXB 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 TRXB 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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