Casdin Capital, LLC - 13 May 2025 Form 4 Insider Report for 2seventy bio, Inc. (TSVT)

Reporting relationship: Director
Issuer ticker: TSVT
Reported as of: 13 May 2025
Net transaction value: -$10,113,125
SEC form: 4
Accepted by SEC: 15 May 2025, 16:51:03 UTC
Prior SEC filing: 05 Aug 2024
Next SEC filing: 22 Aug 2025
Source filing: View source filing
Reporting owner signature: Casdin Capital LLC, By: /s/ Eli Casdin, Managing Member

Key filing fact

Casdin Capital, LLC filed Form 4 for 2seventy bio, Inc. (TSVT) on 15 May 2025.

Key facts

This page summarizes Casdin Capital, LLC's Form 4 filing for 2seventy bio, Inc. (TSVT).
4 reported transactions and 2 derivative rows are listed below.
Accepted by SEC: 15 May 2025, 16:51.

Change

Previous filing in this sequence was filed on 05 Aug 2024.
Current net transaction value: -$10,113,125.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (4)

CIK 0001534261 Primary reporting owner

Casdin Capital, LLC

Relationship: Director
Address: 1350 AVENUE OF THE AMERICAS, SUITE 2600, NEW YORK
Signature: Casdin Capital LLC, By: /s/ Eli Casdin, Managing Member
Signature date: 15 May 2025

CIK 0001534264

Casdin Eli

Relationship: Director
Address: 1350 AVENUE OF THE AMERICAS, SUITE 2600, NEW YORK
Signature: /s/ Eli Casdin, Eli Casdin
Signature date: 15 May 2025

CIK 0001534265

Casdin Partners Master Fund, L.P.

Relationship: Director
Address: 1350 AVENUE OF THE AMERICAS, SUITE 2600, NEW YORK
Signature: Casdin Partners Master Fund, LP, By: Casdin Partners GP, LLC, its General Partner, By: /s/ Eli Casdin, Managing Member
Signature date: 15 May 2025

CIK 0001534260

Casdin Partners GP, LLC

Relationship: Director
Address: 1350 AVENUE OF THE AMERICAS, SUITE 2600, NEW YORK
Signature: Casdin Partners GP LLC, By: /s/ Eli Casdin, Managing Member
Signature date: 15 May 2025

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

TSVT transaction

Common Stock, par value $0.0001 per share

Disposition pursuant to a tender of shares in a change of control transaction

Transaction value: $113,125
Shares: -22,625
Change %: -100%
Price: $5.00
Shares after: 0
Date: 13 May 2025
Ownership: Direct
Footnotes: F1, F2, F3

TSVT transaction

Common Stock, par value $0.0001 per share

Disposition pursuant to a tender of shares in a change of control transaction

Transaction value: $10,000,000
Shares: -2,000,000
Change %: -100%
Price: $5.00
Shares after: 0
Date: 13 May 2025
Ownership: See footnote
Footnotes: F1, F2, F4

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

TSVT transaction Derivative

Stock Options (Right to buy)

Disposed to Issuer

Transaction value
Shares: -12,050
Change %: -100%
Price
Shares after: 0
Date: 13 May 2025
Ownership: Direct
Underlying class: Common Stock, par value $0.0001 per share
Underlying amount: 12,050
Exercise price: $3.93
Footnotes: F3, F5

TSVT transaction Derivative

Stock Options (Right to buy)

Disposed to Issuer

Transaction value
Shares: -33,400
Change %: -100%
Price
Shares after: 0
Date: 13 May 2025
Ownership: Direct
Underlying class: Common Stock, par value $0.0001 per share
Underlying amount: 33,400
Exercise price: $4.54
Footnotes: F3, F5

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Section 16 status

Casdin Capital, LLC is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may still apply in specific circumstances.

Explanation of responses 5 footnotes

Footnote F1

Represents securities that were tendered in connection with the Agreement and Plan of Merger (the "Merger Agreement"), dated March 10, 2025, by and among 2seventy bio, Inc. (the "Company"), Daybreak Merger Sub Inc. ("Merger Sub") and Bristol-Myers Squibb Company ("Parent"). Following completion of a cash tender offer by Merger Sub to acquire all of the issued and outstanding shares of the Company's common stock, par value $0.0001 per share (the "Company Common Stock") for $5.00 per share (the "Merger Consideration"), Merger Sub merged with and into the Company, with the Company continuing as the surviving corporation and a whole owned subsidiary of Parent (the "Merger").

Footnote F2

cont'd from footnote (1): Each restricted stock unit in respect of Company Common Stock ("Company RSU Award"), whether vested or unvested, that was outstanding immediately prior to the effective time of the Merger (the "Effective Time") was fully vested, was cancelled and automatically converted into the right to receive, for each share of Company Common Stock underlying such Company RSU Award immediately prior to the Effective Time, an amount (without interest and subject to deduction for any required withholding under applicable law relating to tax) in cash equal to the Merger Consideration. Additionally, effective as of the Effective Time and as a result of the Merger, Eli Casdin ceased to be a member of the Company's board of directors.

Footnote F3

The securities were owned directly by Eli Casdin.

Footnote F4

The securities were owned directly by Casdin Partners Master Fund, L.P. (the "Master Fund") and may be deemed to have been indirectly beneficially owned by (i) Casdin Capital, LLC, the investment adviser to the Master Fund ("Casdin"), (ii) Casdin Partners GP, LLC, the general partner of the Master Fund (the "GP"), and (iii) Eli Casdin, the managing member of Casdin and the GP.

Footnote F5

Each option to purchase Company Common Stock ("Company Option"), whether vested or unvested, that was outstanding and unexercised immediately prior to the Effective Time and had a per share exercise price that was less than the Merger Consideration was fully vested, was cancelled and automatically converted into the right to receive, for each share of Company Common Stock underlying such Company Option immediately prior to the Effective Time, an amount (without interest and subject to deduction for any required withholding under applicable law relating to tax) in cash equal to the excess of the Merger Consideration over the per share exercise price of such Company Option.

SEC remarks

Each Reporting Person disclaims beneficial ownership in the securities reported on this Form 4 except to the extent of its pecuniary interest, if any, therein, and this report shall not be deemed to be an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or for any other purpose.