Celestica, Inc.

Item 1.01. Entry into a Material Definitive Agreement. On August 5, 2026, Celestica Inc. (the “Company”) entered into an underwriting agreement (the “Underwriting Agreement”) with Citigroup Global Markets Inc., BofA Securities, Inc. and TD Securities Inc., as representatives of the several underwriters named therein (collectively, the “Underwriters”), in connection with the offering, issuance and sale by the Company of 9,677,419 common shares, without par value, of the Company (the “Common Shares”), at an offering price of $310.00 per Common Share (the “Offering”). In addition, under the terms of the Underwriting Agreement, the Company granted the Underwriters the option, for 30 days, to purchase up to 1,451,612 Common Shares at the offering price, which the Underwriters exercised in full on August 6, 2026. The Offering was made pursuant to a registration statement on Form S-3 (Registration No. 333-285515) filed on March 3, 2025, including a base prospectus contained therein, and a prospectus supplement dated August 5, 2026. The Company estimates the net proceeds from the Offering will be approximately $3.39 billion, after deducting underwriting discounts and commissions and estimated offering expenses payable by the Company. The Company intends to use the net proceeds of the Offering for working capital and to support investments in capital expenditures, in addition to other general corporate purposes. The Underwriting Agreement contains customary representations, warranties and agreements by the Company, customary conditions to closing, indemnification obligations of the Company and the Underwriters, including for liabilities under the Securities Act of 1933, as amended, other obligations of the parties and termination provisions. The foregoing descriptions of the Underwriting Agreement are not complete and are qualified in their entirety by reference to the full text of the Underwriting Agreement, a copy of which is filed as Exhibit 1.1 to this Current Report on Form 8-K and is incorporated by reference herein. Blake, Cassels & Graydon LLP, Canadian counsel to the Company, has issued an opinion regarding the validity of the foregoing securities offered and sold in the Offering, a copy of which is filed as Exhibit 5.1 hereto.