SEC ownership of Theseus Pharmaceuticals, Inc.

Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0001745020.

Comparable stake leader

TAKEDA PHARMACEUTICAL CO LTD

Disclosed value leader

TAKEDA PHARMACEUTICAL CO LTD

Comparable rows

0/11

Latest evidence

14 Feb 2024

Ownership snapshot CIK-linked ownership evidence from parsed SEC filings. 1 signal
Latest parsed ownership date
14 Feb 2024
Freshness: Most recent filing date in this holder set
Issuer Names, identifiers, and filing context for this profile. 2 identity fields
Issuer CIK
0001745020
Issuer location
Cambridge, MA

Ownership snapshot

Top shareholders of Theseus Pharmaceuticals, 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
TAKEDA PHARMACEUTICAL CO LTD
Disclosed value leader
TAKEDA PHARMACEUTICAL CO LTD
Comparable rows
0/11
Latest evidence
14 Feb 2024
3/4/5 Highest disclosed value: $4,927,052 11 rows are not safely comparable across share classes. Showing 1-8 of 11 holder rows.

Quick read

TAKEDA PHARMACEUTICAL CO LTD has the largest disclosed position value at $4.93M.

0 of 11 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 TAKEDA PHARMACEUTICAL CO LTD's linked filing trail.
Disclosed position value Top 5
TAKEDA PHARMACEUTICAL CO LTD $4.93M
Foresite Capital Management V, LLC $4.23M
Omega Fund VI, L.P. $2.17M
Rock Springs Capital Management LP $1.83M
William Shakespeare $2.02M

Value bars compare disclosed positions; verify each figure against the linked filing evidence.

Detailed SEC evidence table Showing 1-8 of 11 holder rows
Holder Evidence Ownership % Position 12M Net Δ As of
TAKEDA PHARMACEUTICAL CO LTD
3/4/5
10%+ Owner
—
class O/S missing
$4,927,052
1,615,427 shares
— 12 Oct 2021
Foresite Capital Management V, LLC
3/4/5
10%+ Owner
—
class O/S missing
$4,226,766
1,385,825 shares
— 17 Jul 2023
Omega Fund VI, L.P.
3/4/5
Former 10% owner
—
class O/S missing
$2,170,011
711,479 shares
— 12 Oct 2021
Rock Springs Capital Management LP
3/4/5
10%+ Owner
—
class O/S missing
$1,827,926
599,320 shares
— 12 Oct 2021
William Shakespeare
3/4/5
President of Research and Development
—
mixed-class rows
$2,015,007
753,918 shares
mixed-class rows
— 06 Nov 2023
Timothy P. Clackson
3/4/5
President and CEO, Director
—
mixed-class rows
$139,156
319,375 shares
mixed-class rows
— 01 Mar 2023
David Kerstein
3/4/5
Chief Medical Officer
—
class O/S missing
$53,375
17,500 shares
— 01 Mar 2023
Victor Rivera
3/4/5
Chief Scientific Officer
—
class O/S missing
$49,563
16,250 shares
— 01 Mar 2023
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

Insider buy and sell flow is broadly balanced over the last 12 months. No Buy or Sell transactions have been reported since 05 Oct 2025.

Buys
$0
Insiders: 0
Sells
$0
Insiders: 0
Net
$0
Shares: 0
Window
Last 12 months
4 rolling buckets
Buy value Sell value
Shares: 0 Shares: 0
Window (months) Buy shares Sell shares Buy value Sell value Net value
0-3 0 0 $0 $0 $0
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 1-17 of 17 reporting-owner rows connected to Theseus Pharmaceuticals, Inc.. Open a relationship link for the CIK-to-CIK filing trail.

Rows
17
Largest Forms 3/4/5 holder
TAKEDA PHARMACEUTICAL CO LTD
Net 12M change
$0
Latest report
14 Feb 2024
Name Relationship Holdings Value Past Year Net Change Change % Valuation Report Date
TAKEDA PHARMACEUTICAL CO LTD 10%+ Owner $4,927,052 Mixed 12 Oct 2021
Foresite Capital Management V, LLC 10%+ Owner $4,226,766 Filing P/S 17 Jul 2023
Omega Fund VI, L.P. Former 10% owner $2,170,011 Mixed 12 Oct 2021
William Shakespeare President of Research and Development $2,015,007 Mixed 06 Nov 2023
Rock Springs Capital Management LP 10%+ Owner $1,827,926 Mixed 12 Oct 2021
Timothy P. Clackson President and CEO, Director $139,156 Mixed 01 Mar 2023
David Kerstein Chief Medical Officer $53,375 Mixed 01 Mar 2023
Victor Rivera Chief Scientific Officer $49,563 Mixed 01 Mar 2023
Kathy Yi Director $0 Mixed 14 Feb 2024
Steven H. Stein Director $0 Mixed 14 Feb 2024
ORBIMED ADVISORS LLC Director, 10%+ Owner $0 Mixed 14 Feb 2024
Donald J. Hayden Jr. Director $0 Mixed 14 Feb 2024
Carl L. Gordon Director, 10%+ Owner $0 Mixed 14 Feb 2024
Iain D. Dukes Director $0 Mixed 14 Feb 2024
Bradford D. Dahms President and CFO $0 Mixed 14 Feb 2024
David Dalgarno Chief Technical Officer Mixed 18 Feb 2022
Michael E. Rome Director Mixed 06 Oct 2021

Recent insider transactions for Theseus Pharmaceuticals, 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
No insider transactions were found in the last 12 months for this issuer.
* marks a reported price that did not pass the local price check.
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