Results of Operations

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 o 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 29, 2024 CECO ENVIRONMENTAL CORP. (Exact Name of registrant as specified in its charter) Delaware 000-7099 13-2566064 (State or other jurisdiction of incorporation) (Commission File Number) (IRS Employer Identification No.) 5080 Spectrum Drive East Tower , Suite 800E Addison , Texas 75001 (Address of principal executive offices) (Zip Code) Registrant’s telephone number, including area code: ( 214 ) 357-6181 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 Name of each exchange on which registered Common Stock, par value $0.01 per share CECO The NASDAQ Stock Market LLC 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 2.02. Results of Operations and Financial Condition. On October 29, 2024, CECO Environmental Corp. (the “Company”) issued a press release announcing its financial results for the third quarter ended September 30, 2024. A copy of the press release is furnished as Exhibit 99.1 to this report and is incorporated herein by reference. The information in this Item 2.02, including the exhibit, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such filing. Item 9.01. Financial Statements and Exhibits. (d) Exhibits Exhibit Number Exhibit Title     99.1   104         Press Release, CECO Environmental Reports Third Quarter 2024 Results   Cover 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.     Date: October 29, 2024   CECO Environmental Corp.             By: /s/ Kiril Kovachev       Kiril Kovachev       Chief Accounting Officer