Heartflow (HTFL): BCLS Fund III reports 8.45M-share, 9.8% ownership stake

Rhea-AI Filing Summary

BCLS Fund III Investments, LP, a Delaware limited partnership affiliated with Bain Capital Life Sciences, reports its beneficial ownership of Heartflow, Inc. common stock in this Amendment No. 2. As of the close of business on June 30, 2026, it held 8,448,158 shares of common stock.

These holdings represent approximately 9.8% of Heartflow’s outstanding common stock, based on 86,240,828 shares outstanding as of April 30, 2026 as reported by Heartflow. The Bain Capital Life Sciences entities have shared voting and dispositive power over all 8,448,158 shares and no sole voting or dispositive power.

Key Figures

Shares beneficially owned: 8,448,158 shares Percent of class: 9.8% Shares outstanding: 86,240,828 shares +2 more

5 metrics

Shares beneficially owned 8,448,158 shares Heartflow common stock held by BCLS Fund III Investments as of June 30, 2026

Percent of class 9.8% Portion of Heartflow outstanding common stock represented by 8,448,158 shares

Shares outstanding 86,240,828 shares Heartflow common stock outstanding as of April 30, 2026, per Form 10-Q

Sole voting power 0 shares Shares for which BCLS Fund III has sole voting power

Shared voting power 8,448,158 shares Shares for which Bain Capital Life Sciences entities share voting power

Key Terms

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

5 terms

beneficially owned financial

"Amount beneficially owned: As of the close of business on June 30, 2026, the Reporting Person held"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

shared voting power financial

"Shared Voting Power 8,448,158.00 7 | Sole Dispositive Power 0.00 8 | Shared Dispositive"

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

"Shared Voting Power 8,448,158.00 7 | Sole Dispositive Power 0.00 8 | Shared Dispositive"

percent of class financial

"(b) | Percent of class: See Item 4(a) hereof."

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.

Schedule 13G regulatory

"The percentage of the outstanding shares of Common Stock held by the Reporting Person is based"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

FAQ

What percentage of Heartflow, Inc. (HTFL) does BCLS Fund III Investments own?

BCLS Fund III Investments beneficially owns approximately 9.8% of Heartflow’s common stock. This is based on 8,448,158 shares held versus 86,240,828 shares outstanding as of April 30, 2026, as reported by Heartflow.

How many Heartflow (HTFL) shares are held by BCLS Fund III Investments?

BCLS Fund III Investments holds 8,448,158 shares of Heartflow common stock. The stake is reported as of the close of business on June 30, 2026, and reflects shared voting and dispositive power over all of these shares.

What is the ownership structure behind BCLS Fund III Investments in Heartflow (HTFL)?

The reporting holder is BCLS Fund III Investments, LP, whose general partner is managed through a chain of Bain Capital Life Sciences entities. Bain Capital Life Sciences Investors, LLC may be deemed to share voting and dispositive power over the reported shares.

Does BCLS Fund III Investments have sole or shared voting power over Heartflow (HTFL) shares?

BCLS Fund III Investments reports 0 shares with sole voting power and 8,448,158 shares with shared voting power. It also reports no sole dispositive power and the same 8,448,158 shares with shared dispositive power.

On what share count is BCLS Fund III’s 9.8% Heartflow (HTFL) stake based?

The 9.8% ownership is calculated using 86,240,828 shares of Heartflow common stock outstanding as of April 30, 2026, as disclosed by Heartflow in its Form 10-Q for the quarter ended March 31, 2026.

When was BCLS Fund III’s Heartflow (HTFL) ownership reported and signed?

The ownership position is stated as of June 30, 2026. The filing is signed by Nicholas Downing, Partner of Bain Capital Life Sciences Investors, LLC, on August 14, 2026, certifying the reported information.

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

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Available on EDGAR 08/14/2026 - 07:00 AM Accepted by SEC EDGAR 08/14/2026 - 07:00 AM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 2)

Heartflow, Inc.

(Name of Issuer)

Common Stock, $0.001 par value per share

(Title of Class of Securities)

42238D107

(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)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 42238D107

1

Names of Reporting Persons

BCLS Fund III Investments, LP

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 8,448,158.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 8,448,158.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

8,448,158.00

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)

9.80 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Heartflow, Inc.
(b)	Address of issuer's principal executive offices: 135 Main Street, Suite 1000, San Francisco, California, 94105.
Item 2.
(a)	Name of person filing: This Schedule 13G is being filed by BCLS Fund III Investments, LP, a Delaware limited partnership (the "Reporting Person"). Bain Capital Life Sciences Investors, LLC, a Delaware limited liability company ("BCLSI"), is the manager of Bain Capital Life Sciences III General Partner, LLC, a Delaware limited liability company ("BCLS Fund III GP"), which is the general partner of Bain Capital Life Sciences Fund III, L.P., a Delaware limited partnership ("BCLS Fund III"), which is the managing member of BCLS Fund III Investments GP, LLC, a Delaware limited liability company (together with the Reporting Person, BCLSI, BCLS Fund III GP and BCLS Fund III, the "Bain Capital Life Sciences Entities"), which is the general partner of the Reporting Person. As a result, BCLSI may be deemed to share voting and dispositive power with respect to the securities held by the Reporting Person.
(b)	Address or principal business office or, if none, residence: The principal business address for each of the Bain Capital Life Sciences Entities is 200 Clarendon Street, Boston, Massachusetts 02116.
(c)	Citizenship: Each of the Bain Capital Life Sciences Entities is organized under the laws of the State of Delaware.
(d)	Title of class of securities: Common Stock, $0.001 par value per share
(e)	CUSIP No.: 42238D107
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: As of the close of business on June 30, 2026, the Reporting Person held 8,448,158 shares of Common Stock, representing approximately 9.8% of the outstanding Common Stock. The percentage of the outstanding shares of Common Stock held by the Reporting Person is based on 86,240,828 shares of Common Stock outstanding as of April 30, 2026, as reported by the Issuer in its Quarterly Report on Form 10-Q for the quarter ended March 31, 2026, filed with the Securities and Exchange Commission on May 14, 2026.
(b)	Percent of class: See Item 4(a) hereof.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 8,448,158
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 8,448,158
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:
	Not Applicable

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.

BCLS Fund III Investments, LP

Signature:	/s/ Nicholas Downing
Name/Title:	Nicholas Downing, Partner of Bain Capital Life Sciences Investors, LLC
Date:	08/14/2026