SEC ownership of TRex Bio, Inc.

Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0002139097.

Comparable stake leader

ELI LILLY & Co

Disclosed value leader

Alexandria Venture Investments, LLC

Comparable rows

5/16

Latest evidence

13 Oct 2026

Top shareholders Insider holders Latest transactions
Parsed ownership sources
13D/G and 3/4/5
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
Largest SEC-reported holder
ELI LILLY & Co
Ranking: Comparable ownership first, then disclosed value
Ownership snapshot CIK-linked ownership evidence from parsed SEC filings. 3 signals
Comparable ownership rows
5 of 16
Meaning: Rows with safely comparable ownership %
Latest 13D/G holder
ELI LILLY & Co
Source: Latest parsed Schedule 13D/G stake
Latest parsed ownership date
13 Oct 2026
Freshness: Most recent filing date in this holder set
Issuer Names, identifiers, and filing context for this profile. 2 identity fields
Issuer CIK
0002139097
Issuer location
South San Francisco, CA

Ownership snapshot

Top shareholders of TRex Bio, Inc. (13F + 13D/G + 3/4/5)

Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.

Comparable stake leader
ELI LILLY & Co
Disclosed value leader
Alexandria Venture Invest...
Comparable rows
5/16
Latest evidence
13 Oct 2026
13D/G 3/4/5 Lead comparable stake: 20% 11 rows are not safely comparable across share classes. 13D/G row: ELI LILLY & Co Showing 1-8 of 16 holder rows.

Quick read

ELI LILLY & Co leads the comparable SEC ownership view at 20%.

5 of 16 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.

Open SEC evidence Opens ELI LILLY & Co's linked filing trail.
Comparable ownership Top 5
ELI LILLY & Co 20%
PFIZER INC 7.2%
SV Biotech Crossover Opportunitie... 7%
Johnson & Johnson Innovation - JJ... 5.3%
Alexandria Venture Investments, LLC 4.9%

Ownership % is shown only when SEC disclosures are safely comparable across share classes.

Detailed SEC evidence table Showing 1-8 of 16 holder rows
Holder Evidence Ownership % Position 12M Net Δ As of
ELI LILLY & Co
13D/G 3/4/5
10%+ Owner
13D/G 3/4/5
20%
—
5,480,872 shares
 $0 13 Oct 2026
PFIZER INC
13D/G
PFIZER INC. (13-5315170)
13D/G
7.2%
—
1,965,066 shares
 $0 08 Oct 2026
SV Biotech Crossover Opportunities Fund LP
13D/G
13D/G
7%
—
1,920,667 shares
 $0 08 Oct 2026
Johnson & Johnson Innovation - JJDC, Inc.
13D/G
13D/G
5.3%
—
1,475,302 shares
 $0 13 Oct 2026
Alexandria Venture Investments, LLC
3/4/5
10%+ Owner
3/4/5
4.9%
$18,851,014
1,346,501 shares
 +$2,499,994 13 Oct 2026
SV Life Sciences Fund VI (GP), L.P.
3/4/5
10%+ Owner
3/4/5
—
class O/S missing
—
3,011,818 shares
 — 08 Oct 2026
SV Life Sciences Fund VI, L.P.
3/4/5
10%+ Owner
3/4/5
—
class O/S missing
—
3,011,818 shares
 — 08 Oct 2026
SVLSF VI, LLC
3/4/5
10%+ Owner
3/4/5
—
class O/S missing
—
3,011,818 shares
 — 08 Oct 2026
How to read this table

Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.

Forms 3/4/5 flow

Insider trading overview

Net insider flow leans to buying over the last 12 months. Net value: +$2,499,994.

Buys
$2,499,994
Insiders: 1
Sells
$0
Insiders: 0
Net
+$2,499,994
Shares: +178,571
Window
Last 12 months
4 rolling buckets
Buy value Sell value
Shares: 178,571 Shares: 0
Window (months) Buy shares Sell shares Buy value Sell value Net value
0-3 178,571 0 $2,499,994 $0 +$2,499,994
3-6 0 0 $0 $0 $0
6-9 0 0 $0 $0 $0
9-12 0 0 $0 $0 $0

Reporting owners

Insider holders from Forms 3/4/5

Showing 1-16 of 16 reporting-owner rows connected to TRex Bio, Inc.. Open a relationship link for the CIK-to-CIK filing trail.

Rows
16
Largest Forms 3/4/5 holder
Alexandria Venture Investments, LLC
Net 12M change
+$2,499,994
Latest report
13 Oct 2026
Name Relationship Holdings Value Past Year Net Change Change % Valuation Report Date
Alexandria Venture Investments, LLC 10%+ Owner $18,851,014 +$2,499,994 +15% Filing P/S 13 Oct 2026
ELI LILLY & Co 10%+ Owner Mixed 08 Oct 2026
Ariella Kelman Chief Medical Officer Mixed 08 Oct 2026
Joel S. Marcus Director Mixed 13 Oct 2026
Carol Giltner Gallagher Director Mixed 08 Oct 2026
Marion Johnston Erwin Jr. Chief Executive Officer, Director Mixed 08 Oct 2026
Ali Zarrin Chief Scientific Officer Mixed 08 Oct 2026
Julie Ann Gilmore Director Mixed 08 Oct 2026
Travis Alan Coy Director Mixed 08 Oct 2026
Brandon Hants Chief Financial Officer Mixed 08 Oct 2026
Laura Berner Chief Operating Officer Mixed 08 Oct 2026
Michael Jay Ross Director Mixed 08 Oct 2026
Peter Hirth Director Mixed 08 Oct 2026
SVLSF VI, LLC 10%+ Owner Mixed 08 Oct 2026
SV Life Sciences Fund VI (GP), L.P. 10%+ Owner Mixed 08 Oct 2026
SV Life Sciences Fund VI, L.P. 10%+ Owner Mixed 08 Oct 2026

Recent insider transactions for TRex Bio, Inc.

Showing up to 300 recent insider transactions from the last 12 months.

Insider Symbol Class Transaction % SEC-reported value SEC-reported price Shares Shares owned Date Ownership
Alexandria Venture Investments, LLC Common Stock Purchase 15.3% $2,499,994 $14.00 178,571 1,346,501 13 Oct 2026 Direct
Alexandria Venture Investments, LLC Common Stock Conversion of derivative security 1,167,930 1,167,930 13 Oct 2026 Direct
Alexandria Venture Investments, LLC Series B Preferred Stock Conversion of derivative security -100% -3,480,387 0 13 Oct 2026 Direct
Alexandria Venture Investments, LLC Series A-3 Preferred Stock Conversion of derivative security -100% -1,033,541 0 13 Oct 2026 Direct
Joel S. Marcus Common Stock Conversion of derivative security 41,871 41,871 13 Oct 2026 Direct
Joel S. Marcus Series B Convertible Preferred Stock Conversion of derivative security -100% -161,828 0 13 Oct 2026 Direct
Svlsf Vi, Llc Common Stock Conversion of derivative security 669,939 669,939 13 Oct 2026 By SV Trex Coinvestment, L.P.
Svlsf Vi, Llc Common Stock Conversion of derivative security 669,939 669,939 13 Oct 2026 By SV Trex Coinvestment, L.P.
Svlsf Vi, Llc Common Stock Conversion of derivative security 669,939 669,939 13 Oct 2026 By SV Trex Coinvestment, L.P.
Svlsf Vi, Llc Common Stock Conversion of derivative security 953.9% 70,169 77,525 13 Oct 2026 By SV Life Sciences Fund VI Strategic Partners, L.P.
Svlsf Vi, Llc Common Stock Conversion of derivative security 953.9% 70,169 77,525 13 Oct 2026 By SV Life Sciences Fund VI Strategic Partners, L.P.
Svlsf Vi, Llc Common Stock Conversion of derivative security 953.9% 70,169 77,525 13 Oct 2026 By SV Life Sciences Fund VI Strategic Partners, L.P.
Svlsf Vi, Llc Common Stock Conversion of derivative security 953.8% 2,049,485 2,264,354 13 Oct 2026 By SV Life Sciences Fund VI, L.P.
Svlsf Vi, Llc Common Stock Conversion of derivative security 953.8% 2,049,485 2,264,354 13 Oct 2026 By SV Life Sciences Fund VI, L.P.
Svlsf Vi, Llc Common Stock Conversion of derivative security 953.8% 2,049,485 2,264,354 13 Oct 2026 By SV Life Sciences Fund VI, L.P.
Svlsf Vi, Llc Series B Preferred Stock Conversion of derivative security -100% -669,939 0 13 Oct 2026 By SV Trex Coinvestment, L.P.
Svlsf Vi, Llc Series B Preferred Stock Conversion of derivative security -100% -669,939 0 13 Oct 2026 By SV Trex Coinvestment, L.P.
Svlsf Vi, Llc Series B Preferred Stock Conversion of derivative security -100% -669,939 0 13 Oct 2026 By SV Trex Coinvestment, L.P.
Svlsf Vi, Llc Series B Preferred Stock Conversion of derivative security -100% -16,277 0 13 Oct 2026 By SV Life Sciences Fund VI Strategic Partners, L.P.
Svlsf Vi, Llc Series B Preferred Stock Conversion of derivative security -100% -16,277 0 13 Oct 2026 By SV Life Sciences Fund VI Strategic Partners, L.P.
Svlsf Vi, Llc Series B Preferred Stock Conversion of derivative security -100% -16,277 0 13 Oct 2026 By SV Life Sciences Fund VI Strategic Partners, L.P.
Svlsf Vi, Llc Series A Preferred Stock Conversion of derivative security -100% -53,892 0 13 Oct 2026 By SV Life Sciences Fund VI Strategic Partners, L.P.
Svlsf Vi, Llc Series A Preferred Stock Conversion of derivative security -100% -53,892 0 13 Oct 2026 By SV Life Sciences Fund VI Strategic Partners, L.P.
Svlsf Vi, Llc Series A Preferred Stock Conversion of derivative security -100% -53,892 0 13 Oct 2026 By SV Life Sciences Fund VI Strategic Partners, L.P.
Svlsf Vi, Llc Series B Preferred Stock Conversion of derivative security -100% -475,411 0 13 Oct 2026 By SV Life Sciences Fund VI, L.P.
Svlsf Vi, Llc Series B Preferred Stock Conversion of derivative security -100% -475,411 0 13 Oct 2026 By SV Life Sciences Fund VI, L.P.
Svlsf Vi, Llc Series B Preferred Stock Conversion of derivative security -100% -475,411 0 13 Oct 2026 By SV Life Sciences Fund VI, L.P.
Svlsf Vi, Llc Series A Preferred Stock Conversion of derivative security -100% -1,574,074 0 13 Oct 2026 By SV Life Sciences Fund VI, L.P.
Svlsf Vi, Llc Series A Preferred Stock Conversion of derivative security -100% -1,574,074 0 13 Oct 2026 By SV Life Sciences Fund VI, L.P.
Svlsf Vi, Llc Series A Preferred Stock Conversion of derivative security -100% -1,574,074 0 13 Oct 2026 By SV Life Sciences Fund VI, L.P.
Svlsf Vi, Llc Common Stock Purchase 71.8% 3,074 7,356 08 Oct 2026 By SV Life Sciences Fund VI Strategic Partners, L.P.
Svlsf Vi, Llc Common Stock Purchase 71.8% 3,074 7,356 08 Oct 2026 By SV Life Sciences Fund VI Strategic Partners, L.P.
Svlsf Vi, Llc Common Stock Purchase 71.8% 3,074 7,356 08 Oct 2026 By SV Life Sciences Fund VI Strategic Partners, L.P.
Svlsf Vi, Llc Common Stock Purchase 71.8% 89,783 214,869 08 Oct 2026 By SV Life Sciences Fund VI, L.P.
Svlsf Vi, Llc Common Stock Purchase 71.8% 89,783 214,869 08 Oct 2026 By SV Life Sciences Fund VI, L.P.
Svlsf Vi, Llc Common Stock Purchase 71.8% 89,783 214,869 08 Oct 2026 By SV Life Sciences Fund VI, L.P.
Joel S. Marcus Stock Option (Right to Buy) Award 17,500 17,500 08 Oct 2026 Direct
Travis Alan Coy Stock Option (Right to Buy) Award 17,500 17,500 08 Oct 2026 Direct
Michael Jay Ross Stock Option (Right to Buy) Award 17,500 17,500 08 Oct 2026 Direct
Peter Hirth Stock Option (Right to Buy) Award 17,500 17,500 08 Oct 2026 Direct
Carol Giltner Gallagher Stock Option (Right to Buy) Award 17,500 17,500 08 Oct 2026 Direct
Julie Ann Gilmore Stock Option (Right to Buy) Award 17,500 17,500 08 Oct 2026 Direct
* marks a reported price that did not pass the local price check.
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