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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549 |
SCHEDULE 13G
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UNDER THE SECURITIES EXCHANGE ACT OF 1934
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Seaport Therapeutics, Inc. (Name of Issuer) |
Voting Common Stock, $0.001 par value per share (Title of Class of Securities) |
(CUSIP Number) |
06/30/2026 (Date of Event Which Requires Filing of this Statement) |
| Check the appropriate box to designate the rule pursuant to which this Schedule is filed: |
 Rule 13d-1(b)
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| Rule 13d-1(c)
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 Rule 13d-1(d)
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SCHEDULE 13G
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| CUSIP No. |
| 1 | Names of Reporting Persons
PureTech Health plc | ||||||||
| 2 | Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
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| 3 | Sec Use Only | ||||||||
| 4 | Citizenship or Place of Organization
UNITED KINGDOM
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| Number of Shares Beneficially Owned by Each Reporting Person With: |
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| 9 | Aggregate Amount Beneficially Owned by Each Reporting Person
16,685,013.00 | ||||||||
| 10 | Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
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| 11 | Percent of class represented by amount in row (9)
31.2 % | ||||||||
| 12 | Type of Reporting Person (See Instructions)
CO |
SCHEDULE 13G
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| CUSIP No. |
| 1 | Names of Reporting Persons
PureTech Health LLC | ||||||||
| 2 | Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
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| 3 | Sec Use Only | ||||||||
| 4 | Citizenship or Place of Organization
DELAWARE
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| Number of Shares Beneficially Owned by Each Reporting Person With: |
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| 9 | Aggregate Amount Beneficially Owned by Each Reporting Person
16,685,013.00 | ||||||||
| 10 | Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
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| 11 | Percent of class represented by amount in row (9)
31.2 % | ||||||||
| 12 | Type of Reporting Person (See Instructions)
OO |
Comment for Type of Reporting Person: Limited Liability Company
SCHEDULE 13G
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| CUSIP No. |
| 1 | Names of Reporting Persons
PureTech LYT, Inc. | ||||||||
| 2 | Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
| ||||||||
| 3 | Sec Use Only | ||||||||
| 4 | Citizenship or Place of Organization
DELAWARE
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| Number of Shares Beneficially Owned by Each Reporting Person With: |
| ||||||||
| 9 | Aggregate Amount Beneficially Owned by Each Reporting Person
16,685,013.00 | ||||||||
| 10 | Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
| ||||||||
| 11 | Percent of class represented by amount in row (9)
31.2 % | ||||||||
| 12 | Type of Reporting Person (See Instructions)
CO |
SCHEDULE 13G
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| Item 1. | ||
| (a) | Name of issuer:
Seaport Therapeutics, Inc. | |
| (b) | Address of issuer's principal executive offices:
101 Seaport Blvd., Floor 12, Boston MA 02210 | |
| Item 2. | ||
| (a) | Name of person filing:
Each of the following is hereinafter individually referred to as a "Reporting Person" and collectively as the "Reporting Persons." This statement is filed on behalf of: PureTech Health plc, PureTech Health LLC and PureTech LYT, Inc. | |
| (b) | Address or principal business office or, if none, residence:
The principal business address of each of the Reporting Persons is 6 Tide Street, Suite 400, Boston, MA 02210 | |
| (c) | Citizenship:
PureTech Health plc is a public limited company organized under the laws of the United Kindom. PureTech Health LLC is a limited liability company and PureTech LYT, Inc. is a corporation, both organized under the laws of the State of Delaware. | |
| (d) | Title of class of securities:
Voting Common Stock, $0.001 par value per share | |
| (e) | CUSIP No.:
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| Item 3. | If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a: | |
| (a) | Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
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| (b) | Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
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| (c) | Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
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| (d) | Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
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| (e) | An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
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| (f) | An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
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| (g) | A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
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| (h) | A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
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| (i) | A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
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| (j) | A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution: | |
| (k) | Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
| |
| Item 4. | Ownership | |
| (a) | Amount beneficially owned:
The ownership information presented below represents beneficial ownership of the shares of Voting Common Stock (the "Common Stock") as of June 30, 2026, based upon 53,530,550 shares of Common Stock outstanding as of July 27, 2026, as disclosed in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on August 3, 2026.
PureTech LYT, Inc. is the record holder of the Common Stock reported herein. PureTech Health LLC is the sole owner of PureTech LYT, Inc., and PureTech Health plc is the sole member of PureTech Health LLC, and has the power to direct the voting and disposition of securities held by PureTech LYT, Inc. and PureTech Health LLC. As such, PureTech Health LLC and PureTech Health plc may be deemed to beneficially own all of the shares of Common Stock held directly by PureTech LYT, Inc. | |
| (b) | Percent of class:
31.2% %
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| (c) | Number of shares as to which the person has:
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| (i) Sole power to vote or to direct the vote:
0 | ||
| (ii) Shared power to vote or to direct the vote:
16,685,013 | ||
| (iii) Sole power to dispose or to direct the disposition of:
0 | ||
| (iv) Shared power to dispose or to direct the disposition of:
16,685,013 | ||
| Item 5. | Ownership of 5 Percent or Less of a Class. | |
| Item 6. | Ownership of more than 5 Percent on Behalf of Another Person. | |
Not Applicable
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| Item 7. | Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person. | |
Not Applicable
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| Item 8. | Identification and Classification of Members of the Group. | |
Not Applicable
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| Item 9. | Notice of Dissolution of Group. | |
Not Applicable
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| Item 10. | Certifications: |
Not Applicable
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| SIGNATURE | |
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.
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Exhibit Information
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Exhibit 99.1: Joint Filing Agreement |