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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): | October 21, 2025

MUELLER INDUSTRIES INC.
(Exact name of registrant as specified in its charter)

Delaware | 1-6770 | 25-0790410
(State or other jurisdiction | (Commission File | (IRS Employer
of incorporation) | Number) | Identification No.)

150 Schilling Boulevard | Suite 100 |
Collierville | Tennessee | 38017
(Address of principal executive offices) | (Zip Code)

Registrant’s telephone number, including area code: | (901) | 753-3200

Registrant’s Former Name or Address, if changed since last report: | N/A

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ | Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
☐ | Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
☐ | Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
☐ | Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class | Trading Symbol | Name of exchange on which registered
Common Stock | MLI | NYSE

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).
Emerging growth company ☐
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new of revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02. | Results of Operations and Financial Condition.

On October 21, 2025, the Registrant issued a press release announcing earnings for the quarter ended September 27, 2025. A copy of the press release announcing the third quarter 2025 earnings is attached as Exhibit 99.1.

Item 9.01. | Financial Statements and Exhibits.

(d) Exhibits

| 99.1 | Press release, dated October 21, 2025 reporting third quarter 2025 earnings.

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SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this Report to be signed on its behalf by the undersigned hereunto duly authorized.

| MUELLER INDUSTRIES, INC.
| By: | /s/ ANTHONY J. STEINRIEDE |
| Name: | Anthony J. Steinriede
| Title: | Vice President - Corporate Controller
October 21, 2025 |  |

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Exhibit Index

Exhibit No. | Description
99.1 | Press release, dated October 21, 2025

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