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dco-202602260000030305FALSE600Anton Boulevard, Suite 1100Costa MesaCalifornia00000303052026-02-262026-02-26

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): February 26, 2026

DUCOMMUN INCORPORATED

(Exact name of registrant as specified in its charter)

Delaware001-08174 95-0693330 (State or other jurisdiction of incorporation)(Commission File Number) (IRS Employer Identification No.)

600Anton Boulevard, Suite 1100 , Costa Mesa, California 92626-7100 (Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code (657) 335-3665 N/A (Former name or former address, if changed since last report.)

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:

☐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(s)Name of each exchange on which registered Common Stock, $.01 par value per share DCONew York Stock Exchange

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 or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.¨

Item 2.02Results of Operations and Financial Condition.

Ducommun Incorporated issued a press release on February 26, 2026 in the form attached hereto as Exhibit 99.1.

Item 9.01Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.Exhibit Title or Description 99.1 Ducommun Incorporated press release issued on February 26, 2026.

104Cover Page Interactive Data File (embedded within the Inline XBRL document).

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.

DUCOMMUN INCORPORATED

(Registrant)

Date: February 26, 2026 By:/s/ Suman B. Mookerji Suman B. Mookerji Senior Vice President, Chief Financial Officer

dco-202511060000030305FALSE600 Anton Boulevard, Suite 1100Costa MesaCalifornia00000303052025-11-062025-11-06

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): November 6, 2025

DUCOMMUN INCORPORATED

(Exact name of registrant as specified in its charter)

Delaware001-08174 95-0693330 (State or other jurisdiction of incorporation)(Commission File Number) (IRS Employer Identification No.)

600 Anton Boulevard, Suite 1100 , Costa Mesa, California 92626-7100 (Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code (657) 335-3665 N/A (Former name or former address, if changed since last report.)

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:

☐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(s)Name of each exchange on which registered Common Stock, $.01 par value per share DCONew York Stock Exchange

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 or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.¨

Item 2.02Results of Operations and Financial Condition.

Ducommun Incorporated issued a press release on November 6, 2025 in the form attached hereto as Exhibit 99.1.

Item 9.01Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.Exhibit Title or Description 99.1 Ducommun Incorporated press release issued on November 6, 2025.

104Cover Page Interactive Data File (embedded within the Inline XBRL document).

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.

DUCOMMUN INCORPORATED

(Registrant)

Date: November 6, 2025 By:/s/ Suman B. Mookerji Suman B. Mookerji Senior Vice President, Chief Financial Officer