T. Rowe Price reports 4.9% stake in Quest Diagnostics

T. Rowe Price Associates, Inc. filed an amended Schedule 13G reporting its beneficial ownership in Quest Diagnostics Inc. (common stock).

Rhea-AI Filing Summary

T. Rowe Price Associates, Inc. filed an amended Schedule 13G reporting its beneficial ownership in Quest Diagnostics Inc. (common stock). The firm reports beneficial ownership of 5,428,244 shares, representing 4.9% of the class. It has sole voting power over 5,321,387 shares and sole dispositive power over 5,428,244 shares, with no shared voting or dispositive power. T. Rowe Price Associates states that this filing should not be construed as an admission that it is the beneficial owner of these securities, and such beneficial ownership is expressly denied.

Key Figures

Beneficially owned shares: 5,428,244 shares Percent of class: 4.9% Sole voting power: 5,321,387 shares +3 more

6 metrics

Beneficially owned shares 5,428,244 shares Common stock of Quest Diagnostics reported by T. Rowe Price Associates

Percent of class 4.9% Portion of Quest Diagnostics common stock class reported as beneficially owned

Sole voting power 5,321,387 shares Shares over which T. Rowe Price Associates has sole power to vote or direct the vote

Shared voting power 0 shares Shares over which T. Rowe Price Associates has shared voting power

Sole dispositive power 5,428,244 shares Shares over which T. Rowe Price Associates has sole power to dispose or direct disposition

Shared dispositive power 0 shares Shares over which T. Rowe Price Associates has shared dispositive power

Key Terms

beneficially owned, sole voting power, sole dispositive power, Ownership of 5 percent or Less of a Class

4 terms

beneficially owned financial

"Amount beneficially owned: 5428244"

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 voting power financial

"Sole power to vote or to direct the vote: 5321387"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

sole dispositive power financial

"Sole power to dispose or to direct the disposition of: 5428244"

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.

Ownership of 5 percent or Less of a Class regulatory

"Ownership of 5 Percent or Less of a Class."

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What percentage of Quest Diagnostics (DGX) does T. Rowe Price Associates report owning?

T. Rowe Price Associates reports beneficial ownership of 4.9% of Quest Diagnostics’ common stock. This corresponds to 5,428,244 shares as disclosed in the Schedule 13G/A amendment.

How many Quest Diagnostics (DGX) shares does T. Rowe Price Associates claim to beneficially own?

T. Rowe Price Associates reports beneficial ownership of 5,428,244 Quest Diagnostics common shares. This holding represents 4.9% of the outstanding common stock class, according to the Schedule 13G/A filing.

What voting power does T. Rowe Price Associates have over Quest Diagnostics (DGX) shares?

T. Rowe Price Associates reports sole voting power over 5,321,387 shares of Quest Diagnostics common stock, with no shared voting power, as disclosed in the Schedule 13G/A amendment.

What dispositive power over Quest Diagnostics (DGX) shares is reported by T. Rowe Price Associates?

The firm reports sole dispositive power over 5,428,244 shares and no shared dispositive power. This means it alone can direct the disposition of those reported Quest Diagnostics shares.

Does T. Rowe Price Associates admit beneficial ownership of Quest Diagnostics (DGX) shares in this filing?

No. T. Rowe Price Associates explicitly states that the filing shall not be construed as an admission of beneficial ownership of the Quest Diagnostics securities, and such beneficial ownership is expressly denied.

What type of security in Quest Diagnostics (DGX) is reported in this Schedule 13G/A?

The filing covers Quest Diagnostics’ common stock, identified with CUSIP 74834L100. T. Rowe Price Associates reports ownership and voting/dispositive powers only with respect to this class of securities.

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

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Available on EDGAR 08/14/2026 - 10:39 AM Accepted by SEC EDGAR 08/14/2026 - 10:38 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)

QUEST DIAGNOSTICS INC

(Name of Issuer)

COMMON STOCK

(Title of Class of Securities)

74834L100

(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): 74834L100

1

Names of Reporting Persons

T. Rowe Price Associates, Inc.

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

MARYLAND

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 5,321,387.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 5,428,244.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

5,428,244.00

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)

4.9 %

12

Type of Reporting Person (See Instructions)

IA

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: T. Rowe Price Associates, Inc.
(b)	Address or principal business office or, if none, residence: 1307 Point Street, Baltimore, MD 21231
(c)	Citizenship: Maryland
(d)	Title of class of securities: COMMON STOCK
(e)	CUSIP No.: 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: 5428244
(b)	Percent of class: 4.9 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 5321387
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 5428244
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
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 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. T. Rowe Price Associates, Inc. hereby declares and affirms that the filing of Schedule 13G shall not be construed as an admission that Price Associates is the beneficial owner of the securities referred to, which beneficial ownership is expressly denied.

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.

T. Rowe Price Associates, Inc.

Signature:	Ellen York
Name/Title:	Vice President
Date:	08/14/2026