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): January 28, 2026

CALIX, INC.

(Exact name of Registrant as specified in its charter)

Delaware

001-34674

68-0438710

(State or other jurisdiction
of incorporation)

(Commission
File No.)

(I.R.S. Employer
Identification No.)

3155 Olsen Drive, Suite 450, San Jose, California

95117

(Address of principal executive offices)

(Zip Code)


(408) 514-3000
(Registrant’s telephone number, including area code)


Not Applicable
(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

Name of Each Exchange on Which Registered

Common Stock, par value $0.025 per share

CALX

New 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). o

Item 2.02 Results of Operations and Financial Condition.

On January 28, 2026, Calix, Inc. (the “Company”) issued a press release announcing it has publicly disseminated a stockholder letter with its financial results for the fourth quarter ended December 31, 2025. The press release is attached hereto as Exhibit 99.1. The stockholder letter, a copy of which is attached hereto as Exhibit 99.2 and incorporated herein by reference, includes reference to the non-GAAP measures of non-GAAP gross margin, non-GAAP operating expenses, non-GAAP sales and marketing investments, non-GAAP research and development investments, non-GAAP general and administrative investments, non-GAAP effective income tax rate, non-GAAP net income or profitability, non-GAAP net income per diluted common share and non-GAAP free cash flow. These non-GAAP measures are provided to enhance the reader’s understanding of the Company’s operating performance as they exclude non-cash stock-based compensation and intangible asset amortization and the impact from changes in income taxes, which the Company believes are not indicative of its core operating results. Management believes that the non-GAAP measures used in this stockholder letter provide investors with important perspectives into the Company’s ongoing business performance and management uses these non-GAAP measures to evaluate financial results and to establish operational goals. The presentation of these non-GAAP measures is not meant to be a substitute for results presented in accordance with U.S. GAAP, but rather should be evaluated in conjunction with those GAAP results. A reconciliation of the non-GAAP results to the most directly comparable U.S. GAAP results is contained in tabular form in Exhibit 99.2. The non-GAAP financial measures used by the Company may be calculated differently from, and therefore may not be comparable to, similarly titled measures used by other companies.

Such information shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and is not incorporated by reference into any filing of the Company, whether made before or after the date hereof, regardless of any general incorporation language in such filing.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits


Exhibit No.						Description
99.1						Press Release, dated January 28 , 202 6 announcing fourth quarter 2025 financial results.
99.2						Stockholder Letter dated Jan uary 2 8 , 202 6 announcing financial results of the Company.

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:

January 28, 2026

CALIX, INC.

By:

/s/ Cory Sindelar

Cory Sindelar

Chief Financial Officer

EXHIBIT INDEX


Exhibit No.						Description
99.1						Press Release, dated January 2 8 , 202 6 announcing four th quarter 2025 financial results.
99.2						Stockholder Letter dated January 28 , 202 6 announcing financial results of the Company.

CALIX, INC 8-K