Vanguard reports 8.27M Quest Diagnostics shares (NYSE: DGX) stake

Rhea-AI Filing Summary

Vanguard Capital Management filed a Schedule 13G reporting beneficial ownership of 8,274,567 shares of Quest Diagnostics Inc Common Stock. The filing states this equals 7.53% of the class as of 03/31/2026, with 1,128,895 shares for which Vanguard has sole voting power and 8,274,567 shares for which it has sole dispositive power. The filing lists affiliated Vanguard entities and notes holdings include securities held for Vanguard funds and managed accounts.

Insights

Institutional Ownership Analyst

Large passive stake disclosed: 8,274,567 shares (7.53%).

Vanguard Capital Management reports a non‑operatorial, beneficial holding representing 7.53% of Quest Diagnostics common stock as of 03/31/2026. The filing attributes voting and dispositive powers across Vanguard affiliates and managed funds.

Because Schedule 13G filings are generally passive disclosures, this is a snapshot of ownership structure; subsequent filings could show changes in percent or voting intent.

Key Figures

Shares beneficially owned: 8,274,567 shares Percent of class: 7.53% Sole voting power: 1,128,895 shares +2 more

5 metrics

Shares beneficially owned 8,274,567 shares Beneficial ownership reported as of 03/31/2026

Percent of class 7.53% Percent of outstanding common stock as reported

Sole voting power 1,128,895 shares Number with sole power to vote

Sole dispositive power 8,274,567 shares Number with sole power to dispose

CUSIP 74834L100 Quest Diagnostics common stock identifier

Key Terms

Schedule 13G, Beneficially owned, Sole dispositive power, Investment Company Act

4 terms

Schedule 13G regulatory

"Vanguard Capital Management filed a Schedule 13G reporting beneficial ownership"

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.

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: 8274567"

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.

Investment Company Act regulatory

"investment companies registered under the Investment Company Act of 1940"

The Investment Company Act is a law that sets rules for businesses whose main activity is managing and selling pooled money, such as mutual funds and other investment funds. It matters to investors because it requires clear reporting, limits managers from putting their own interests ahead of clients, and mandates safekeeping and oversight of assets—similar to safety inspections and traffic rules that help keep shared vehicles reliable and trustworthy.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Quest Diagnostics Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

74834L100

(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): 74834L100

1

Names of Reporting Persons

Vanguard Capital 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 1,128,895.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 8,274,567.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

8,274,567.00

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)

7.53 %

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 Capital Management LLC and the following affiliates of Vanguard Capital Management LLC or business divisions of such affiliates: Vanguard Asset Management Limited, Vanguard Fiduciary Trust Company, Vanguard Global Advisers, LLC and Vanguard Investments Australia Ltd. This Schedule 13G includes securities held by Vanguard funds, or sleeves thereof, over which Vanguard Capital 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 Capital 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: Quest Diagnostics Inc
(b)	Address of issuer's principal executive offices: 500 Plaza Drive, Secaucus, NJ, 07094
Item 2.
(a)	Name of person filing: Vanguard Capital 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): 74834L100
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: 8274567
(b)	Percent of class: 7.53 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 1128895
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 8274567
	(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 Capital 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 Capital Management

Signature:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	04/30/2026

FAQ

What stake does Vanguard Capital Management report in Quest Diagnostics (DGX)?

Vanguard Capital Management reports beneficial ownership of 8,274,567 shares, equal to 7.53% of Quest Diagnostics common stock as of 03/31/2026. The filing lists both voting and dispositive power figures for Vanguard affiliates.

How many shares does Vanguard have sole voting power over in DGX?

The filing states Vanguard has sole voting power over 1,128,895 shares. It also reports sole dispositive power over 8,274,567 shares, per the Schedule 13G disclosure dated 03/31/2026.

Does the Schedule 13G identify which Vanguard entities hold the DGX shares?

Yes. The filing names Vanguard Capital Management LLC and affiliates including Vanguard Asset Management Limited, Vanguard Fiduciary Trust Company, Vanguard Global Advisers, LLC, and Vanguard Investments Australia Ltd as relevant entities exercising power over the shares.

Is Vanguard acting as an active investor in Quest Diagnostics per this filing?

The Schedule 13G format indicates a passive investor disclosure. The filing lists beneficial ownership and powers but does not state active intent to influence management or control; it reports holdings across Vanguard funds and managed accounts.

What CUSIP and class are reported for Quest Diagnostics in this filing?

The filing lists the security as Common Stock with CUSIP 74834L100 for Quest Diagnostics Inc. The ownership figures reported relate specifically to that class of common stock.