United States securities and exchange commission logo





                                May 3, 2024

       Cory Sindelar
       Chief Financial Officer
       Calix, Inc.
       2777 Orchard Parkway
       San Jose, California 95134

                                                        Re: Calix, Inc.
                                                            Form 10-K for the
Fiscal Year Ended December 31, 2023
                                                            Form 8-K/A filed
February 23, 2024
                                                            File No. 001-34674

       Dear Cory Sindelar:

                                                        We have reviewed your
filing and have the following comments.

              Please respond to this letter within ten business days by
providing the requested
       information or advise us as soon as possible when you will respond. If
you do not believe a
       comment applies to your facts and circumstances, please tell us why in
your response.

                                                        After reviewing your
response to this letter, we may have additional comments.

       Form 10-K for the Fiscal Year Ended December 31, 2023

       Management's Discussion and Analysis of Financial Condition and Results
of Operations, page
       27

   1.                                                   We note you mention
small, medium, and large size customers and average-revenue-per-
                                                        user, but do not
quantify this statistical data. In future filings, please quantify statistical
                                                        data, for all periods
presented, that will enhance a reader's understanding of the financial
                                                        conditions and results
of operations. We refer to guidance in Item 303 of Regulation S-K.
                                                        Provide us with your
proposed future disclosure.
       Critical Accounting Policies and Estimates, page 28

   2.                                                   Please disclose in your
critical accounting policies and estimates disclosure the actual
                                                        judgements and
assumptions used by management. For example, when you have multiple
                                                        performance obligations
you should describe how stand alone selling price was
                                                        determined for each
performance obligation. For inventory impairment, you should
                                                        provide more detail and
disclose the specific assumptions used when testing inventory for
                                                        impairment in fiscal
year 2022 and 2023. Provide us with your proposed future disclosure.
 Cory Sindelar
Calix, Inc.
May 3, 2024
Page 2
Results of Operations for Years Ended December 31, 2023 and 2022, page 29

3.       We note your disclosure that your revenue increased by $171.8 million,
or 20%, during
         2023 compared with 2022. You disclose that "the increase in revenue
was primarily due to
         strength in shipments to one of our large customers, continued
shipments throughout 2023
         from a new medium-sized BSP customer that we added in the third
quarter of 2022 and
         higher revenue from our growing base of small and medium BSP
customers." When more
         than one factor is responsible for the change in an income statement
line item,
         quantify each of the contributing factors, including any offsetting
amounts. Please ensure
         this change is made throughout your MD&A including in your discussion
of gross profit
         and gross margin. Provide us with your proposed future disclosure.
Form 8-K/A filed February 23, 2024

Exhibit 99.1
Use of Non-GAAP Financial Information, page 13

4.       We note you exclude inventory and component liability charges that
occurred during the
         year ended December 31, 2023 from non-GAAP financial measures. Given
the nature of
         your business, which appears to include customer orders for products
and services, it is
         not clear to us how you determined this non-GAAP adjustment is
appropriate and
         consistent with the requirements of Question 100.01 of the Division of
Corporation
         Finance   s Compliance & Disclosure Interpretations on Non-GAAP
Financial Measures.
         Although this inventory-write off may be unusual due to its size,
based on the nature of
         this adjustment and your business, it appears to us that risks related
to inventory and
         significant customers are normal operating expenses that arise in the
ordinary course of
         your business. Please advise or revise in future filings. Provide us
with your proposed
         future disclosure.
5.       Tell us why you believe litigation settlement is an appropriate
non-GAAP adjustment.
         Refer to your basis in accounting literature.
        We remind you that the company and its management are responsible for
the accuracy
and adequacy of their disclosures, notwithstanding any review, comments, action
or absence of
action by the staff.

       Please contact Inessa Kessman at 202-551-3371 or Robert Littlepage at
202-551-3361 if
you have questions regarding comments on the financial statements and related
matters.



FirstName LastNameCory Sindelar                              Sincerely,
Comapany NameCalix, Inc.
                                                             Division of
Corporation Finance
May 3, 2024 Page 2                                           Office of
Technology
FirstName LastName