Company: CALX
Filing Date: 2025-07-22
Form Type: S-8
Source: 0001406666-25-000036
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Company: CALIX, INC
Filing Date: 2025-07-22
Form: S-8
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 new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ¨

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### EXPLANATORY NOTE
This Registration Statement on Form S-8 (this “Registration Statement”) registers (1) an additional 4,000,000 shares of common stock at $0.025 par value per share (the “Common Stock”) of Calix, Inc. (the “Registrant”) issuable under the Calix, Inc. Amended and Restated 2019 Equity Incentive Award Plan (the “2019 Plan”), (2) 2,923,400 shares of Common Stock of the Registrant available for future issuance for the purchase component of the non-executive Calix, Inc. Stock Purchase and Matching Plan, which constitutes an amendment and restatement of the Third Amended and Restated 2017 Nonqualified Employee Stock Purchase Plan (such plan, as amended and restated as of the date hereof, the “Stock Purchase and Matching Plan”), and (3) 1,250,000 shares of Common Stock of the Registrant available for future issuance for the matching component of the Stock Purchase and Matching Plan.

### REGISTRATION OF ADDITIONAL SECURITIES
By a Registration Statement on Form S-8 filed with the Securities and Exchange Commission (the “SEC”) on October 28, 2019 (File No. 333-234355) (the “2019 Plan Original Registration Statement”), the Registrant registered 3,149,038 shares of Common Stock available for future issuance under the 2019 Plan. By a Registration Statement on Form S-8 filed with the SEC on July 27, 2020 (File No. 333-240106) (the “2019 Plan 2020 Registration Statement”), the Registrant registered an additional 4,807,598 shares of Common Stock issuable under the 2019 Plan. By a Registration Statement on Form S-8 filed with the SEC on July 27, 2021 (File No. 333-258197) (the “2019 Plan 2021 Registration Statement”), the Registrant registered an additional 3,816,970 shares of Common Stock issuable under the 2019 Plan. By a Registration Statement on Form S-8 filed with the SEC on July 26, 2022 (File No. 333-266335) (the “2019 Plan 2022 Registration