Obsidian Therapeutics (OBX): Atlas Venture funds disclose 7.3% ownership stake

Rhea-AI Filing Summary

Obsidian Therapeutics, Inc. has a significant shareholder group composed of multiple Atlas Venture investment funds and related entities. These reporting persons collectively beneficially own 4,503,149 shares of Obsidian’s common stock, representing 7.3% of the outstanding shares.

Atlas Venture Fund X, L.P. and its related entities report beneficial ownership of 2,642,587 shares, or 4.3% of the common stock. Three Atlas Venture Opportunity Funds and their associated general partners and LLCs report additional stakes of 1.7%, 0.9%, and 0.3%, respectively. The reporting persons share voting and dispositive power over their respective blocks and state that they may be deemed a group but expressly disclaim group status.

Key Figures

Fund X shares owned: 2,642,587 shares Fund X percent of class: 4.3% Opportunity Fund I shares owned: 1,069,278 shares +5 more

8 metrics

Fund X shares owned 2,642,587 shares Atlas Venture Fund X, L.P. record ownership of common stock

Fund X percent of class 4.3% Beneficial ownership of Obsidian outstanding common stock

Opportunity Fund I shares owned 1,069,278 shares Atlas Venture Opportunity Fund I, L.P. record ownership

Opportunity Fund I percent 1.7% Beneficial ownership of outstanding common stock

Opportunity Fund II shares owned 582,960 shares Atlas Venture Opportunity Fund II, L.P. record ownership

Opportunity Fund III shares owned 208,324 shares Atlas Venture Opportunity Fund III, L.P. record ownership

Aggregate shares owned 4,503,149 shares Total shares beneficially owned by all reporting persons

Aggregate percent of class 7.3% Total beneficial ownership of outstanding common stock

Key Terms

beneficially own, shared voting power, shared dispositive power, percent of class, +1 more

5 terms

beneficially own financial

"Collectively, the Reporting Persons beneficially own an aggregate of 4,503,149 shares"

Beneficially own means having the economic rights and risks of a security—such as the right to receive dividends, sell the shares, or profit from price changes—whether or not your name appears on the official share register. Think of it like renting a car: you use it and reap the benefits even if the title lists someone else. Investors care because beneficial ownership determines who truly controls value, must be disclosed under securities rules, and can signal potential influence or trading activity that affects a stock’s price.

shared voting power financial

"Each Fund X Reporting Person shares power to vote or direct the vote of 2,642,587 shares"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

shared dispositive power financial

"shares power to dispose or to direct the disposition of 2,642,587 shares of Common Stock"

percent of class financial

"Collectively, the Reporting Persons beneficially own 4,503,149 shares of Common Stock, which represents 7.3% of the Issuer's outstanding Common Stock"

Percent of class is the portion of a specific category of securities—such as a company’s common shares, preferred shares, or a bond series—that takes part in or approves a corporate action (vote, consent, tender, etc.). Investors watch this number because it reveals how much support or opposition exists within that particular shareholder group; like counting how many members of a club back a proposal, it can determine whether a plan passes or how influence is distributed.

Section 13 regulatory

"this shall not be deemed an admission that the Reporting Persons are members of a group for purposes of Section 13"

Section 13 of the U.S. Securities Exchange Act requires public companies and large shareholders to disclose important ownership and reporting information to the market, including regular financial reports and filings when someone builds a significant stake. For investors it acts like a public checkbook and alert system: it provides verified updates on a company’s health and who controls it, helping buyers judge risk, spot takeover activity, and make informed decisions.

FAQ

How much of Obsidian Therapeutics (OBX) do the Atlas Venture entities own?

The Atlas Venture reporting entities collectively beneficially own 4,503,149 shares of Obsidian Therapeutics common stock, representing 7.3% of the company’s outstanding shares, according to the Schedule 13G ownership disclosure.

What is Atlas Venture Fund X’s stake in Obsidian Therapeutics (OBX)?

Atlas Venture Fund X, L.P. and its related entities beneficially own 2,642,587 shares of Obsidian common stock, representing 4.3% of the outstanding shares, with shared voting and dispositive power over this block.

How many Obsidian Therapeutics (OBX) shares does Atlas Venture Opportunity Fund I hold?

Atlas Venture Opportunity Fund I, L.P. and its related entities beneficially own 1,069,278 shares of Obsidian common stock, equal to 1.7% of the outstanding class, and share both voting and dispositive power over these shares.

What ownership percentages do Atlas Venture Opportunity Funds II and III report in OBX?

Atlas Venture Opportunity Fund II and its related entities report 582,960 shares (0.9% of Obsidian’s common stock), while Atlas Venture Opportunity Fund III and related entities report 208,324 shares (0.3% of the class).

Do the Atlas Venture entities have sole or shared voting power over OBX shares?

The reporting entities disclose no sole voting or dispositive power. Each fund group has shared voting and shared dispositive power over its respective block of Obsidian common stock as detailed in the Schedule 13G.

Do the Atlas Venture entities claim to be a group under Section 13 for OBX?

The funds are under common control and state they may be deemed members of a group, but they expressly disclaim such group membership and clarify that the filing is not an admission of group status.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/11/2026 - 08:03 PM Accepted by SEC EDGAR 08/10/2026 - 04:43 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Obsidian Therapeutics, Inc.

(Name of Issuer)

Common stock, par value $0.001 per share

(Title of Class of Securities)

67448A106

(CUSIP Number)

08/03/2026

(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)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 67448A106

1

Names of Reporting Persons

Atlas Venture Fund X, 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 2,642,587.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,642,587.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,642,587.00

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)

4.3 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 67448A106

1

Names of Reporting Persons

ATLAS VENTURE ASSOCIATES X, 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 2,642,587.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,642,587.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,642,587.00

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)

4.3 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 67448A106

1

Names of Reporting Persons

Atlas Venture Associates X, 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 2,642,587.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,642,587.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,642,587.00

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)

4.3 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

CUSIP Number(s): 67448A106

1

Names of Reporting Persons

Atlas Venture Opportunity Fund I, 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 1,069,278.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,069,278.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,069,278.00

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)

1.7 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 67448A106

1

Names of Reporting Persons

Atlas Venture Associates Opportunity I, 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 1,069,278.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,069,278.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,069,278.00

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)

1.7 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 67448A106

1

Names of Reporting Persons

Atlas Venture Associates Opportunity I, 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 1,069,278.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,069,278.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,069,278.00

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)

1.7 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

CUSIP Number(s): 67448A106

1

Names of Reporting Persons

Atlas Venture Opportunity 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 582,960.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 582,960.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

582,960.00

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)

0.9 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 67448A106

1

Names of Reporting Persons

Atlas Venture Associates Opportunity 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 582,960.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 582,960.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

582,960.00

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)

0.9 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 67448A106

1

Names of Reporting Persons

Atlas Venture Associates Opportunity 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 582,960.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 582,960.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

582,960.00

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)

0.9 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

CUSIP Number(s): 67448A106

1

Names of Reporting Persons

Atlas Venture Opportunity 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 208,324.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 208,324.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

208,324.00

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)

0.3 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 67448A106

1

Names of Reporting Persons

Atlas Venture Associates Opportunity 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 208,324.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 208,324.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

208,324.00

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)

0.3 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP Number(s): 67448A106

1

Names of Reporting Persons

Atlas Venture Associates Opportunity 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 208,324.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 208,324.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

208,324.00

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)

0.3 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Obsidian Therapeutics, Inc.
(b)	Address of issuer's principal executive offices: 1030 Massachusetts Avenue, Cambridge, MA, 02138.
Item 2.
(a)	Name of person filing: This Schedule 13G is filed by (i) Atlas Venture Fund X, L.P., a Delaware limited partnership ("Atlas X"), (ii) Atlas Venture Associates X, L.P., a Delaware limited partnership ("AVA X LP"), (iii) Atlas Venture Associates X, LLC, a Delaware limited liability company ("AVA X LLC" and together with Atlas X and AVA X LP, the "Fund X Reporting Persons"), (iv) Atlas Venture Opportunity Fund I, L.P., a Delaware limited partnership ("AVOF I"), (v) Atlas Venture Associates Opportunity I, L.P., a Delaware limited partnership ("AVAO I LP"), (vi) Atlas Venture Associates Opportunity I, LLC, a Delaware limited liability company ("AVAO I LLC" and together with AVOF I and AVAO I LP, the "Opportunity Fund I Reporting Persons"), (vii) Atlas Venture Opportunity Fund II, L.P., a Delaware limited partnership ("AVOF II"), (viii) Atlas Venture Associates Opportunity II, L.P., a Delaware limited partnership ("AVAO II LP"), (ix) Atlas Venture Associates Opportunity II, LLC, a Delaware limited liability company ("AVAO II LLC" and together with AVOF II and AVAO II LP, the "Opportunity Fund II Reporting Persons"), (x) Atlas Venture Opportunity Fund III, L.P., a Delaware limited partnership ("AVOF III"), (xi) Atlas Venture Associates Opportunity III, L.P., a Delaware limited partnership ("AVAO III LP") and (xii) Atlas Venture Associates Opportunity III, LLC, a Delaware limited liability company ("AVAO III LLC" and together with AVOF III and AVAO III LP, the "Opportunity Fund III Reporting Persons" and together with the Fund X Reporting Persons, the Opportunity Fund I Reporting Persons, and the Opportunity Fund II Reporting Persons, the "Reporting Persons").
(b)	Address or principal business office or, if none, residence: 300 Technology Square, 8th Floor Cambridge, Massachusetts 02139
(c)	Citizenship: Each of Atlas X, AVA X LP, AVOF I, AVAO I LP, AVOF II, AVAO II LP, AVOF III and AVAO III LP is a Delaware limited partnership. Each of AVA X LLC, AVAO I LLC, AVAO II LLC and AVAO III LLC is a Delaware limited liability company.
(d)	Title of class of securities: Common stock, par value $0.001 per share
(e)	CUSIP Number(s): 67448A106
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: Atlas X is the record owner of 2,642,587 shares of Common Stock. AVA X LP is the general partner of Atlas X and AVA X LLC is the general partner of AVA X LP. Each of Atlas X, AVA X LP and AVA X LLC may be deemed to beneficially own the shares held by Atlas X. AVOF I is the record owner of 1,069,278 shares of Common Stock. AVAO I LP is the general partner of AVOF I and AVAO I LLC is the general partner of AVAO I LP. Each of AVOF I, AVAO I LP and AVAO I LLC may be deemed to beneficially own the shares held by AVOF I. AVOF II is the record owner of 582,960 shares of Common Stock. AVAO II LP is the general partner of AVOF II and AVAO II LLC is the general partner of AVAO II LP. Each of AVOF II, AVAO II LP and AVAO II LLC may be deemed to beneficially own the shares held by AVOF II. AVOF III is the record owner of 208,324 shares of Common Stock. AVAO III LP is the general partner of AVOF III and AVAO III LLC is the general partner of AVAO III LP. Each of AVOF III, AVAO III LP and AVAO III LLC may be deemed to beneficially own the shares held by AVOF III.
(b)	Percent of class: Each of the Fund X Reporting Persons may be deemed to beneficially own 4.3% of the Issuer's outstanding Common Stock. Each of the Opportunity Fund I Reporting Persons may be deemed to beneficially own 1.7% of the Issuer's outstanding Common Stock. Each of the Opportunity Fund II Reporting Persons may be deemed to beneficially own 0.9% of the Issuer's outstanding Common Stock. Each of the Opportunity Fund III Reporting Persons may be deemed to beneficially own 0.3% of the Issuer's outstanding Common Stock. Collectively, the Reporting Persons beneficially own an aggregate of 4,503,149 shares of Common Stock, which represents 7.3% of the Issuer's outstanding Common Stock. The Fund X Reporting Persons, Opportunity Fund I Reporting Persons, Opportunity Fund II Reporting Persons and Opportunity Fund III Reporting Persons are under common control and as a result, the Reporting Persons may be deemed to be members of a group. However, the Reporting Persons disclaim such group membership, and this Schedule 13G shall not be deemed an admission that the Reporting Persons are members of a group for purposes of Section 13 or for any other purposes.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: None of the Reporting Persons have the sole power to direct the vote of the Common Stock.
	(ii) Shared power to vote or to direct the vote: Each Fund X Reporting Person shares power to vote or direct the vote of 2,642,587 shares of Common Stock. Each Opportunity Fund I Reporting Person shares power to vote or direct the vote of 1,069,278 shares of Common Stock. Each Opportunity Fund II Reporting Person shares power to vote or direct the vote of 582,960 shares of Common Stock. Each Opportunity Fund III Reporting Person shares power to vote or direct the vote of 208,324 shares of Common Stock.
	(iii) Sole power to dispose or to direct the disposition of: None of the Reporting Persons have the sole power to dispose or to direct the disposition of the Common Stock.
	(iv) Shared power to dispose or to direct the disposition of: Each Fund X Reporting Person shares power to dispose or to direct the disposition of 2,642,587 shares of Common Stock. Each Opportunity Fund I Reporting Person shares power to dispose or to direct the disposition of 1,069,278 shares of Common Stock. Each Opportunity Fund II Reporting Person shares power to dispose or to direct the disposition of 582,960 shares of Common Stock. Each Opportunity Fund III Reporting Person shares power to dispose or to direct the disposition of 208,324 shares of Common Stock.
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.
	Not Applicable
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.

Atlas Venture Fund X, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	Atlas Venture Associates X, L.P., its general partner, By: Atlas Venture Associates X, LLC, its general partner, By: Ommer Chohan, CFO
Date:	08/10/2026

ATLAS VENTURE ASSOCIATES X, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	Atlas Venture Associates X, LLC, its general partner, By: Ommer Chohan, CFO
Date:	08/10/2026

Atlas Venture Associates X, LLC

Signature:	/s/ Ommer Chohan
Name/Title:	Ommer Chohan, CFO
Date:	08/10/2026

Atlas Venture Opportunity Fund I, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	Atlas Venture Associates Opportunity I, L.P., its GP, By: Atlas Venture Associates Opportunity I, LLC, its GP, By: Ommer Chohan, CFO
Date:	08/10/2026

Atlas Venture Associates Opportunity I, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	Atlas Venture Associates Opportunity I, LLC, its GP, By: Ommer Chohan, CFO
Date:	08/10/2026

Atlas Venture Associates Opportunity I, LLC

Signature:	/s/ Ommer Chohan
Name/Title:	Ommer Chohan, CFO
Date:	08/10/2026

Atlas Venture Opportunity Fund II, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	Atlas Venture Associates Opportunity II, L.P., its GP, By: Atlas Venture Associates Opportunity II, LLC, its GP, By: Ommer Chohan, CFO
Date:	08/10/2026

Atlas Venture Associates Opportunity II, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	Atlas Venture Associates Opportunity II, LLC, its GP, By: Ommer Chohan, CFO
Date:	08/10/2026

Atlas Venture Associates Opportunity II, LLC

Signature:	/s/ Ommer Chohan
Name/Title:	Ommer Chohan, CFO
Date:	08/10/2026

Atlas Venture Opportunity Fund III, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	Atlas Venture Associates Opportunity III, L.P., its GP, By: Atlas Venture Associates Opportunity III, LLC, its GP, By: Ommer Chohan, CFO
Date:	08/10/2026

Atlas Venture Associates Opportunity III, L.P.

Signature:	/s/ Ommer Chohan
Name/Title:	Atlas Venture Associates Opportunity III, LLC, its GP, By: Ommer Chohan, CFO
Date:	08/10/2026

Atlas Venture Associates Opportunity III, LLC

Signature:	/s/ Ommer Chohan
Name/Title:	Ommer Chohan, CFO
Date:	08/10/2026

Exhibit Information

99.1 Joint Filing Agreement