Tectonic Therapeutic, Inc. joint statement reports beneficial ownership positions held by TCG Crossover entities and Chen Yu.
TCG Crossover II and TCG Crossover III each hold 584,882 and 584,878 shares respectively; the Reporting Individual, Chen Yu, is reported as beneficially owning 1,169,760 shares, equal to 6.2% of the class based on 18,776,626 shares outstanding as of February 16, 2026, per the issuer's Form 10-K.
Positive
None.
Negative
None.
Insights
TL;DR: This Schedule 13G discloses a passive, >5% position held through TCG funds and attributed to Chen Yu.
The filing lists holdings of 584,882 and 584,878 shares by TCG Crossover II and III and aggregates those holdings to 1,169,760 shares for Chen Yu, representing 6.2% of the outstanding common stock as of February 16, 2026. The statement characterizes the Reporting Persons as filing jointly under Rule 13d-1(k)(1).
Ownership is shown as shared voting and dispositive power via general partner structures; the filing expressly disclaims group status and attributes holdings through the funds. Subsequent filings would clarify any change in voting control or disposition plans.
TL;DR: The disclosure signals a notable institutional stake but is presented as passive collective ownership.
The excerpt specifies that TCG entities hold two near-equal positions of ~584.9k shares each and that these interests are held of record by TCG Crossover II and III, with voting and dispositive power potentially shared through the general partner and Chen Yu as managing member.
For investors, the key datapoints are the 1,169,760 share aggregate and the 6.2% threshold; any active intentions would require further filings or amendments.
What stake does Chen Yu report in Tectonic Therapeutic (TECX)?
Chen Yu is reported to beneficially own 1,169,760 shares, representing 6.2% of the class. This aggregate equals holdings of two TCG funds and is based on 18,776,626 shares outstanding as of February 16, 2026.
How many shares do TCG Crossover II and III each hold?
TCG Crossover II holds 584,882 shares and TCG Crossover III holds 584,878 shares. Each position is listed with shared voting and dispositive power through their general partner entities.
Does the filing indicate Chen Yu controls the shares directly?
The filing states Chen Yu is the sole managing member of the general partners and may be deemed to share voting and dispositive power. It also notes holdings are held of record by the TCG funds.
On what date is the outstanding share count based?
The ownership percentages are calculated using 18,776,626 shares outstanding as of February 16, 2026, as reported by the issuer in its Form 10-K.
Did the Reporting Persons declare a group for this filing?
The Reporting Persons filed jointly under Rule 13d-1(k)(1) but expressly disclaim status as a group for purposes of the Schedule 13G joint statement.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
Tectonic Therapeutic, Inc.
(Name of Issuer)
Common Stock, $0.0001 par value per share
(Title of Class of Securities)
878972108
(CUSIP Number)
02/12/2026
(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)
Rule 13d-1(c)
Rule 13d-1(d)
SCHEDULE 13G
CUSIP No.
878972108
1
Names of Reporting Persons
TCG Crossover GP II, LLC
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
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
584,882.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
584,882.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
584,882.00
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)
3.1 %
12
Type of Reporting Person (See Instructions)
OO
Comment for Type of Reporting Person:
These securities are held of record by TCG Crossover II (as defined in Item 2(a) below). TCG Crossover GP II (as defined in Item 2(a) below) is the general partner of TCG Crossover II and may be deemed to have voting, investment, and dispositive power with respect to these securities. Chen Yu is the sole managing member of TCG Crossover GP II and may be deemed to share voting, investment and dispositive power with respect to these securities.
Based on 18,776,626 shares of Common Stock outstanding as of February 16, 2026 as reported by the Issuer (as defined in Item 1(a) below) in its Annual Report on Form 10-K, filed with the United States Securities and Exchange Commission (the Commission) on February 26, 2026 (the Form 10-K).
SCHEDULE 13G
CUSIP No.
878972108
1
Names of Reporting Persons
TCG Crossover Fund II, L.P.
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
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
584,882.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
584,882.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
584,882.00
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)
3.1 %
12
Type of Reporting Person (See Instructions)
PN
Comment for Type of Reporting Person:
These securities are held of record by TCG Crossover II. TCG Crossover GP II is the general partner of TCG Crossover II and may be deemed to have voting, investment, and dispositive power with respect to these securities. Chen Yu is the sole managing member of TCG Crossover GP II and may be deemed to share voting, investment and dispositive power with respect to these securities.
Based on 18,776,626 shares of Common Stock outstanding as of February 16, 2026 as reported by the Issuer in the Form 10-K.
SCHEDULE 13G
CUSIP No.
878972108
1
Names of Reporting Persons
TCG Crossover GP III, LLC
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
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
584,878.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
584,878.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
584,878.00
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)
3.1 %
12
Type of Reporting Person (See Instructions)
OO
Comment for Type of Reporting Person:
These securities are held of record by TCG Crossover III (as defined in Item 2(a) below). TCG Crossover GP III (as defined in Item 2(a) below) is the general partner of TCG Crossover III and may be deemed to have voting, investment, and dispositive power with respect to these securities. Chen Yu is the sole managing member of TCG Crossover GP III and may be deemed to share voting, investment and dispositive power with respect to these securities.
Based on 18,776,626 shares of Common Stock outstanding as of February 16, 2026 as reported by the Issuer in the Form 10-K.
SCHEDULE 13G
CUSIP No.
878972108
1
Names of Reporting Persons
TCG Crossover Fund III, L.P.
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
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
584,878.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
584,878.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
584,878.00
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)
3.1 %
12
Type of Reporting Person (See Instructions)
PN
Comment for Type of Reporting Person:
These securities are held of record by TCG Crossover III. TCG Crossover GP III is the general partner of TCG Crossover III and may be deemed to have voting, investment, and dispositive power with respect to these securities. Chen Yu is the sole managing member of TCG Crossover GP III and may be deemed to share voting, investment and dispositive power with respect to these securities.
Based on 18,776,626 shares of Common Stock outstanding as of February 16, 2026 as reported by the Issuer in the Form 10-K.
SCHEDULE 13G
CUSIP No.
878972108
1
Names of Reporting Persons
Chen Yu
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
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
1,169,760.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,169,760.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,169,760.00
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)
6.2 %
12
Type of Reporting Person (See Instructions)
IN
Comment for Type of Reporting Person:
Consists of (i) 584,882 shares of Common Stock held of record by TCG Crossover II and (ii) 584,878 shares of Common Stock held of record by TCG Crossover III. TCG Crossover GP II is the general partner of TCG Crossover II and may be deemed to have voting, investment, and dispositive power with respect to the securities held of record by TCG Crossover II. TCG Crossover GP III is the general partner of TCG Crossover III and may be deemed to have voting, investment, and dispositive power with respect to the securities held of record by TCG Crossover III. Chen Yu is the sole managing member of each of TCG Crossover GP II and TCG Crossover GP III and may be deemed to share voting, investment and dispositive power with respect to the securities held of record by TCG Crossover II and TCG Crossover III.
Based on 18,776,626 shares of Common Stock outstanding as of February 16, 2026 as reported by the Issuer in the Form 10-K.
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Tectonic Therapeutic, Inc.
(b)
Address of issuer's principal executive offices:
490 Arsenal Way, Suite 210, Watertown, MA 02472
Item 2.
(a)
Name of person filing:
This joint statement on Schedule 13G is being filed by TCG Crossover Fund II, L.P. (TCG Crossover II), TCG Crossover GP II, LLC (TCG Crossover GP II), TCG Crossover Fund III, L.P. (TCG Crossover III) and TCG Crossover GP III, LLC (TCG Crossover GP III and together with TCG Crossover II, TCG Crossover GP II and TCG Crossover III, the Reporting Entities) and Chen Yu (the Reporting Individual). The Reporting Entities and the Reporting Individual are collectively referred to as the Reporting Persons. The Reporting Persons expressly disclaim status as a group for purposes of this Schedule 13G. The agreement among the Reporting Persons to file jointly in accordance with the provisions of Rule 13d-1(k)(1) under the Act is attached to this Statement as Exhibit 1. Other than those securities reported herein as being held directly by such Reporting Person, each Reporting Person disclaims beneficial ownership of all securities reported in this Statement except to the extent of such Reporting Person's pecuniary interest therein.
(b)
Address or principal business office or, if none, residence:
The address of the principal business office of each Reporting Person is 245 Lytton Ave., Suite 350, Palo Alto, CA 94301.
(c)
Citizenship:
TCG Crossover GP II and TCG Crossover GP III are each a limited liability company organized under the laws of the State of Delaware. TCG Crossover II and TCG Crossover III are each a limited partnership organized under the laws of the State of Delaware. The Reporting Individual is a citizen of the United States of America.
(d)
Title of class of securities:
Common Stock, $0.0001 par value per share
(e)
CUSIP No.:
878972108
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);
(b)
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)
An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)
An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(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);
(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:
See Row 9 of the cover page for each Reporting Person and the corresponding comments.
(b)
Percent of class:
See Row 11 of the cover page for each Reporting Person and the corresponding comments.
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
See Row 5 of the cover page for each Reporting Person and the corresponding comments.
(ii) Shared power to vote or to direct the vote:
See Row 6 of the cover page for each Reporting Person and the corresponding comments.
(iii) Sole power to dispose or to direct the disposition of:
See Row 7 of the cover page for each Reporting Person and the corresponding comments.
(iv) Shared power to dispose or to direct the disposition of:
See Row 8 of the cover page for each Reporting Person and the corresponding comments.
Item 5.
Ownership of 5 Percent or Less of a Class.
Not Applicable
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required.
Under certain circumstances set forth in the limited partnership agreements of TCG Crossover II and TCG Crossover III and the limited liability company agreements of TCG Crossover GP II and TCG Crossover GP III, the general and limited partners or members, as the case may be, of each of such entities may be deemed to have the right to receive dividends from, or the proceeds from, the sale of securities of the Issuer owned by each such entity of which they are a partner or member, as the case may be.
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
Item 8.
Identification and Classification of Members of the Group.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.
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.
TCG Crossover GP II, LLC
Signature:
/s/ Craig Skaling
Name/Title:
Craig Skaling, Authorized Signatory
Date:
02/27/2026
TCG Crossover Fund II, L.P.
Signature:
/s/ Craig Skaling
Name/Title:
Craig Skaling, Authorized Signatory
Date:
02/27/2026
TCG Crossover GP III, LLC
Signature:
/s/ Craig Skaling
Name/Title:
Craig Skaling, Authorized Signatory
Date:
02/27/2026
TCG Crossover Fund III, L.P.
Signature:
/s/ Craig Skaling
Name/Title:
Craig Skaling, Authorized Signatory
Date:
02/27/2026
Chen Yu
Signature:
/s/ Craig Skaling
Name/Title:
Craig Skaling, as Attorney-in-Fact for Chen Yu
Date:
02/27/2026
Exhibit Information
Exhibit 1: Joint Filing Agreement, dated February 27, 2026, by and among the Reporting Persons (filed herewith).
