Vanguard Portfolio Management holding 5.68% of TransMedics (NASDAQ: TMDX) in Schedule 13G

Rhea-AI Filing Summary

TransMedics Group Inc reports a Schedule 13G filing by Vanguard Portfolio Management holding 1,949,420 shares of Common Stock, representing 5.68% of the class. The filing shows sole voting power for 29,885 shares and sole dispositive power over 1,949,420 shares as reported.

The filing names Vanguard Portfolio Management LLC and affiliated entities as the reporting persons and is signed on 04/29/2026.

Insights

Institutional Ownership Analyst

Vanguard holds a >5% stake in TransMedics, creating visible institutional ownership.

The filing reports 1,949,420 shares representing 5.68% of common stock as of the disclosure. Institutional stakes above 5.00% are routinely disclosed and can affect holder composition and voting dynamics.

Concentration and voting power matter; Vanguard reports sole voting power for 29,885 shares and sole dispositive power for 1,949,420 shares. Subsequent proxy filings may show whether this stake influences governance actions.

Securities & Compliance Counsel

The Schedule 13G filing is a passive investor disclosure under beneficial ownership rules.

The report identifies the reporting entity and provides the CUSIP 89377M109, ownership amount, and percent. The filing text includes the specific disclosure language about affiliate relationships and dispositive power in accordance with SEC guidance.

Filing formalities are satisfied by the signature dated 04/29/2026. Any change in ownership classification or active intent would require an amended filing under applicable rules.

Key Figures

Shares beneficially owned: 1,949,420 shares Percent of class: 5.68% Sole voting power: 29,885 shares +2 more

5 metrics

Shares beneficially owned 1,949,420 shares Amount reported on Schedule 13G

Percent of class 5.68% Percent of common stock reported

Sole voting power 29,885 shares Number of shares with sole voting power reported

Sole dispositive power 1,949,420 shares Number of shares with sole dispositive power reported

CUSIP 89377M109 Identifier for TransMedics common stock

Key Terms

Beneficially owned, Sole dispositive power, Schedule 13G, Shared voting power

4 terms

Beneficially owned regulatory

"reflects the securities beneficially owned, or deemed to be beneficially owned"

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.

Sole dispositive power regulatory

"Sole power to dispose or to direct the disposition of: 1949420"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

Schedule 13G regulatory

"Item 1. Name of issuer: TransMedics Group Inc"

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.

Shared voting power regulatory

"Shared power to vote or to direct the vote: 0"

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.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

TransMedics Group Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

89377M109

(CUSIP Number)

03/31/2026

(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): 89377M109

1

Names of Reporting Persons

Vanguard Portfolio Management

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

PENNSYLVANIA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 29,885.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 1,949,420.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,949,420.00

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)

5.68 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: In accordance with SEC Release No. 34-39538 (January 12, 1998), this Schedule 13G reflects the securities beneficially owned, or deemed to be beneficially owned, by Vanguard Portfolio Management LLC and the following affiliates of Vanguard Portfolio Management LLC or business divisions of such affiliates: Vanguard Fiduciary Trust Company and Vanguard Global Advisers, LLC. This Schedule 13G includes securities held by Vanguard funds, or sleeves thereof, over which Vanguard Portfolio Management LLC exercises dispositive power, in addition to securities held by clients over which the affiliates or business divisions of such affiliates indicated above exercise dispositive and/or voting power. This Schedule 13G does not include securities, if any, beneficially owned by other subsidiaries or affiliates of Vanguard Portfolio Management LLC, or business divisions of such subsidiaries whose ownership of securities is disaggregated from that of the reporting business unit in accordance with such release.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: TransMedics Group Inc
(b)	Address of issuer's principal executive offices: 200 Minuteman Road, Suite 302, Andover, MA, 01810
Item 2.
(a)	Name of person filing: Vanguard Portfolio Management
(b)	Address or principal business office or, if none, residence: 100 Vanguard Blvd,, Malvern, PA, 19355
(c)	Citizenship: PA
(d)	Title of class of securities: Common Stock
(e)	CUSIP Number(s): 89377M109
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: 1949420
(b)	Percent of class: 5.68 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 29885
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 1949420
	(iv) Shared power to dispose or to direct the disposition of: 0
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. Vanguard Portfolio Management, including investment companies registered under the Investment Company Act of 1940 and other managed accounts, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities reported herein.No one other person's interest in the securities reported herein is more than 5%.
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 acquired and are held in the ordinary course of business and 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.

Vanguard Portfolio Management

Signature:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	04/29/2026

FAQ

What stake does Vanguard Portfolio Management report in TransMedics (TMDX)?

Vanguard Portfolio Management reports beneficial ownership of 1,949,420 shares, or 5.68% of TransMedics common stock. The filing states Vanguard exercises sole dispositive power over those shares and sole voting power over 29,885 shares as disclosed in the Schedule 13G.

Does the Schedule 13G filing indicate Vanguard is an active manager for TMDX?

The filing characterizes the position under Schedule 13G disclosure practices for passive ownership. It lists affiliated entities and dispositive authority but does not state an active intent to influence control or governance in the provided excerpt.

What voting and dispositive powers does Vanguard report for TMDX shares?

Vanguard reports sole voting power for 29,885 shares and sole dispositive power for 1,949,420 shares. No shared voting or dispositive powers are reported in the excerpt.

When was the Schedule 13G signed and who signed it for Vanguard?

The Schedule 13G is signed by Ashley Grim, Head of Global Fund Administration, with a signature date of 04/29/2026. The filing lists the reporting address for Vanguard Portfolio Management in Malvern, Pennsylvania.