CALIX, INC (CALX) Business

ITEM 1.    Business

Company Overview

Calix was founded in 1999. We develop, market and sell platform, cloud and managed services, which are powered by agentic AI, that enable communication service providers (“CSPs”) of all types and sizes to innovate and transform their businesses to focus on delivering outstanding subscriber experiences and become CXPs. The platform combines the Calix Agent Workforce™ with intelligent appliances, software, cloud and fully integrated SmartLife™ managed services to enable simplified business models that acquire, retain and grow subscribers and revenue. Calix Customer Success guides service providers through every stage of their transformation journey with expertise across technology, business and market insights. Our partner community extends innovation so customers can grow their businesses across markets at scale. With deep broadband expertise and an end-to-end approach from the datacenters’ access edge to every residential, business and municipal subscriber location, Calix enables any service provider to simplify operations, engagement, and service; innovate for their subscribers; and grow value for members, investors, and the communities they serve. This focus on subscriber experience allows CXPs to expand their brand through increased subscriber acquisition, loyalty and revenue while reducing their operating costs.

This is our mission: to transform service providers of all types and sizes into CXPs and enable them to simplify, innovate and grow.

We believe our platform offers a competitive edge to CXPs at a critical time of increasing competition. With the increase in both private and public funding of broadband access, we anticipate at least two fiber-to-the-home providers vying for subscribers in every market. These providers have a choice: become a speed provider focused on offering the fastest speeds at the lowest price, or become an experience provider focused on delivering innovative, value-added services that improve the lives of their subscribers. Our platform enables these service providers to build next generation networks and offer higher-value, managed-service experiences that enable them to grow revenue, increase subscriber loyalty and monetize their network investments for generations.

CXPs, who embrace our platform, understand this competitive threat and that their brand’s central position in the home, the business and the town is their most valuable strategic asset. As such, they must protect and expand continually. Our Access Edge network solution and Experience Edge premises solution are designed to allow CXPs to simplify their businesses and reduce operating costs, while launching innovative new services in a matter of days and weeks instead of months and years. Our role-based cloud enables CXP teams, such as marketing, operations or customer support, to leverage our Calix Agent Workforce to anticipate and automate tasks to address the subscriber’s needs, whether they are in the home, roaming across the town or managing a small business. Our platform is built to enable CXPs to quickly and easily deploy a growing portfolio of SmartLife managed services to connect entire communities. Embracing this strategy enables CXPs to establish themselves as essential technology innovators that are enabling their communities to grow and thrive.

The CXPs’ teams can utilize AI-driven insights from Calix Cloud to rapidly scale new innovative services for those subscribers who have the propensity to buy, thereby growing revenue as they deliver a connected experience at significantly lower operating costs. This also enables them to build their brand and value proposition around innovation and subscriber experience. As a result, many of Calix’s CXP customers have experienced improved customer satisfaction scores, minimal churn and significant revenue growth. To expand our reach in the market, we will continue to pursue strategic technology and distribution relationships that align with CXPs’ strategic priorities. At the same time, we offer Calix Success Services along with a growing portfolio of award-winning market activation resources that provide CXPs with best practices and programs to strengthen and grow their brands with their subscribers, thereby increasing subscriber loyalty and opportunities to grow their subscriber bases.

Strategy Overview

Our strategy is to position Calix as the key partner providing a broadband delivery platform (agentic AI, cloud, software and appliances) and managed services to enable and facilitate the transformation of service provider networks and the residential, community and business network experience in order to innovate for all of their subscribers. Most service providers will require transformation of their business and operations to become an essential provider of data-driven, high-value managed services to their subscribers. The principal elements of our strategy are:

Start with the data – The principal way we gather, analyze and deliver actionable insights for CXPs is via the Calix Agent Workforce and Cloud. Our role-based Agents and Cloud enable critical functions within a CXP’s business, such as marketing,

4

Table of Contents

operations and support, to leverage real-time data to continually understand, optimize and automate the experience for their subscribers.

Build and evolve our platform – Our product strategy centers on our AI enabled strategic platform. Our platform simplifies CXPs’ businesses by delivering intelligence and automation across the entire subscriber facing network – from the data center edge to the subscriber’s connected devices. Our strategy is to continually augment and extend our platform with AI agents, features and services directly or through partners to allow our CXP customers to deliver cutting-edge services to their subscribers.

Engage directly with CXP customers – We continue to invest in our direct sales capabilities so that we can engage deeply with our customers to help them understand the differentiable value that our platform provides. As we deploy new solutions, we are building the expertise of our team by adding specialized resources in areas such as marketing, customer support, cloud and network operations. Our direct model is complemented with selective programs for our channel partners, who have established local market expertise and have demonstrated the ability to generate new market opportunities and support sales of cutting-edge technologies for CXPs.

Expand our customer footprint across our total addressable opportunity – Our total addressable opportunity includes service providers of any type and size, including managed service providers (“MSPs”), local and competitive exchange carriers, cable multiple system operators (“MSOs”), wireless internet service providers (“WISPs”), fiber overbuilders such as municipalities, electric cooperatives, tribal communities, multiple dwelling units (“MDU”) and hospitality providers. For the past five years, we have averaged landing 80 new customers per year purchasing directly or through our partners. Our diverse and growing customer footprint is a critical source of our future growth as we expand our portfolio and sell additional components of our platform and managed services to both new and existing customers. Our platform enables us to expand our total addressable opportunity and recurring revenue streams by allowing us to address the needs of not only traditional wireline-focused service providers, but also emerging service providers. As such, we intend to continue to engage emerging providers that are creating entirely new customer segments, including fiber overbuilders, utilities, municipalities and MSPs. We will also continue to pursue service provider segments where there is an opportunity to grow our current share, such as cable MSOs, large traditional wireline-focused service providers and international markets.

Extend portfolio of Calix services – Our Success team supports our customers as they define their transformation strategies, build new skills, implement new technologies and deploy new subscriber services. Calix Success’ capabilities address our customers’ entire network and service delivery lifecycle. These services allow our customers to benefit directly from our deep expertise working with service providers of all types and sizes to optimize their operations and leverage our advanced analytics to improve the operational efficiency of their teams.

Pursue strategic relationships – We will continue to pursue strategic technology and distribution relationships that help us align with our customers’ strategic priorities. We continue to invest to provide technical synergy across the ecosystems that support our customers’ most critical business processes through our partner program. By adding new solutions to our platform ecosystem, we significantly enhance the value that our platform delivers to our customers. In addition, we are continuing to expand our relationships with organizations that help our customers plan and execute in-market. Examples of these partners are Conexon, LLC, ePlus Technology, Inc., BroadEngagement (Refindable LLC business), Google LLC and GOCare™ (NuTEQ Solutions, LLC business).

Product Overview

Our product strategy centers on increasing the market adoption of our Calix One Platform, which consists of:

•Calix Cloud®, which comes in three role-based SaaS applications: Calix Engagement Cloud, Calix Operations Cloud and Calix Service Cloud.

•Calix Agent Workforce consists of four agent families:

◦Service Agents share best practices and contextual insights to Customer Service Representatives (“CSRs”) to solve problems faster and on the first call.

◦Subscriber Agents extend the reach of CSRs and Service Agents directly to subscribers through CommandIQ, providing personalized self-service experience optimization, upsell offers and real-time outage information.

◦Operations Agents assist network operations teams around the clock and are dedicated to uncovering and resolving issues to eliminate and reduce service outages and improve subscriber experiences.

◦Marketing Agents continuously scan and analyze market and competitor data to automate subscriber segmentation and create targeted, effective campaigns that amplify the effectiveness of marketing teams.

•Calix Access Edge™ is our access network and subscriber service management solution for automated, intelligent next generation networks.

5

Table of Contents

•Calix Experience Edge™ is our premises Wi-Fi and service delivery solution for subscriber managed services.

•Calix SmartLife managed service offerings, which consist of:

◦SmartHome™ managed services and applications to enhance, operate and secure the connected experience of subscribers in their home, including managed Wi-Fi, advanced content control, network security, connected cameras and social media monitoring for kids.

◦SmartTown® managed services reimagine community Wi-Fi as a secure and managed experience across a CXP’s footprint by making their town a SmartTown. By leveraging residential and small business Wi-Fi appliances combined with strategically deployed outdoor Wi-Fi access points, CXPs can serve subscribers, schools, municipalities, organizations, planned communities, parks, marinas and more. These opportunities open new markets and relationships with the public sector to reduce reliance on and augment 5G mobile networks.

◦SmartBiz™ managed services address the networking and productivity needs of small business owners with an all-in-one solution that increases staff productivity, secures critical business systems and enhances customer loyalty.

◦SmartMDU™ managed services provide purpose-built, flexible connectivity solutions for multi-family properties of any type, enabling service providers and property owners to exceed resident expectations with a simple, secure, personalized and efficient managed Wi-Fi solution.

Each subscriber managed service is complemented by real-time subscriber insights via Calix Engagement Cloud, Calix Operations Cloud offerings and Calix Service Cloud, which are configurable to display role-based insights for general management, marketing, support, operations and engineering staff. Powered by Calix Agent Workforce, these insights enable CXPs to anticipate, target and automate new revenue-generating services and applications through our smart phone applications: CommandIQ® for residents, CommandWorx™ for businesses, PropertyWorx™ for multi-dwelling unit property owners and Field Service App for CXP installers and field technicians. Calix Cloud enables simple integrations with other market-leading workflow solutions for marketing (including Facebook, Mailchimp, Constant Contact and HubSpot), support ticketing solutions, operations support systems and business support systems.

The SmartLife managed services are built on the Calix One platform and fully integrated with our Experience Edge GigaSpire® and GigaPro® family of Wi-Fi appliances to be ready for deployment as a complete market-ready subscriber experience solution for a CXP’s residential subscribers, business subscribers and community networks. Calix customers are evolving their go-to-market strategies to go beyond marketing broadband speed by delivering valuable managed services built on top of their Wi-Fi offerings. This unique portfolio gives them more opportunities to provide differentiated services to their subscribers and grow their revenue.

Our Access Edge network solutions redefine the access edge of the network by simplifying its architecture and operations and reducing energy consumption. Our platform’s access network component is provided by our E-Series family of modular, non-blocking systems, enabling CXPs to meet a wide variety of deployment scenarios. Our customers can consolidate multiple access network elements into a single system using specialized software modules that add functionality and remove complexity, thereby reducing the total cost of ownership and the time to market for new services. Our Access Edge network solutions are also some of the most energy efficient in the industry versus traditional access networks thanks to double-density PON innovations that reduce rack space, cooling requirements and overall power consumption. We offer a range of training, professional and success services to assist CXPs in every domain of network management from strategy to deployment and management.

These offerings are sold independently and offer unique entry points for new customers, who are partnering with Calix to transform their businesses. Moreover, an increased segment of our customer base is leveraging all components of our platform and managed services in an end-to-end strategy to simplify their businesses, innovate for their subscribers and grow the value that they deliver for their consumer, business and municipal subscribers.

Finally, to support these managed services, we offer market activation resources and customer support programs through our Customer Success organization to enable CXP teams to quickly deploy, manage and monetize each service that they provide to subscribers. These resources include marketing content that can be easily customized with on-line tools, training programs and success services.

6

Table of Contents

Customers

We market and sell our platform (agentic AI, cloud, software and appliances) and managed services to service providers of all types and sizes. To date, we have focused primarily on service providers in the North American market. Our customers span all sizes of broadband subscriber count from a few subscribers to more than eleven million. We currently have approximately 1,600 active service provider customers, purchasing directly and through partners, to deploy passive optical, Active Ethernet or point-to-point Ethernet access networks or subscriber premise appliances. Our service provider customers include: ALLO Communications, LLC; Connect Holding II LLC (dba Brightspeed); CityFibre Holdings Limited; Conexon Connect, LLC; Cox Communications, Inc.; Gridiron Fiber Corp. (dba Lumos, a T-Mobile Fiber company); Hunter Communications; ICS Advanced Technologies; Jade Communications, LLC; Rally Networks; South Central Telephone Association, Inc.; Tombigbee Electric Power Association and Tombigbee Fiber, LLC and Verizon Communications Inc.

The U.S. Federal government has approved programs, totaling more than $40 billion, to fund broadband and connectivity expansion across the rural parts of the U.S. Calix has a dedicated team of funding specialists, assisting customers and prospects with the most up-to-date information on broadband funding opportunities as they are introduced and personalized strategies to maximize their grants to support their growth.

We refer to service providers as large, medium and small based on the number of broadband subscribers they serve. Large service providers are those with wide geographic footprints and broadband subscribers of 2.5 million or more. Medium service providers also operate typically within a wide geographic footprint but are smaller in scale with broadband subscribers that range from 250,000 to 2.5 million. Small service providers consist primarily of over 1,000 predominantly local IOCs that are typically focused on a single community or a cluster of communities. They include a growing number of municipalities, cable MSOs, electric cooperatives, fiber overbuilders, tribal entities and WISPs. These entities range in size from a few subscribers to 250,000 broadband subscribers.

No customer represented more than 10% of revenue in 2025, 2024 or 2023. Sales to customers outside the U.S. represented 7% of our revenue in 2025, 8% of our revenue in 2024 and 9% of our revenue in 2023. Our sales outside the U.S. have been and are currently predominantly to customers in the Americas and Europe.

Customer Engagement Model

We market, sell and support the success of our platform and managed services predominantly through our direct sales force, supported by marketing, product management and customer success personnel. We have also expanded this model to include select channel partners in North America and more than 40 international channel partners. Even in circumstances where a channel partner is involved, our sales and marketing personnel are generally selling side-by-side with the channel partner. We believe that our direct customer engagement approach provides us with significant differentiation in the customer sales process and customer engagement programs by aligning us more closely with our customers’ changing needs and successful implementation of our solutions.

Research and Development

Continued investment in research and development is critical to our business. We have made significant investments in our product portfolio, and we intend to continue to dedicate significant resources to research and development to develop, enhance and deliver new platform features and capabilities, including investments in innovative technologies that support our business strategy. Our research and development team is composed of engineers with expertise in software and cloud platforms, agentic AI, optics, wireless technologies and systems engineering. Our research and development team is responsible for designing, developing and enhancing our platform, cloud and managed services, performing product and quality assurance testing and ensuring the compatibility of our products with third-party hardware and software products. Increasingly, our engineers are focused on enhancements to our cloud and software platform components. Our teams of engineers currently remain concentrated in San Jose and Petaluma, California; Nanjing, China; Bangalore, India; Minneapolis, Minnesota and Richardson, Texas. We also outsource a portion of our software and cloud development to domestic and international third parties and depend on these partners to meet our development plans.

Manufacturing and Supply Chain

We rely on CMs, ODMs and third-party logistics partners for the supply and distribution of our products. The global supply-chain organization oversees these third parties to source and procure materials, manufacture and deliver products. This organization includes order management, planning, sourcing, logistics, testing and manufacturing engineers and new product introduction teams. We integrate our supply-chain management and new product introduction activities with those outsourced to third parties. Relationships with and reliance on these third parties allow us to improve new product introduction time, conserve working capital, reduce product costs and minimize delivery lead times while maintaining product quality and scaling quickly to handle increased order volume. We continue to qualify and utilize additional vendors for various portions of the supply chain as needed.

7

Table of Contents

Seasonality

Fluctuations in our revenue occur due to many factors, including the varying budget cycles and seasonal buying patterns of our customers. More specifically, our customers tend to spend less in the first fiscal quarter as they are finalizing their annual capital spending budgets, and in certain regions, customers are also challenged by winter weather conditions that inhibit outside fiber deployment. In recent years, as our revenue from our large customers decreased, we have experienced less year-end volatility due to capital budgetary spending or freezing. This, combined with an increase in recurring revenue, has resulted in smaller seasonal fluctuations, and we expect this trend to continue.

Competition

The communications software and systems equipment markets are highly competitive. Competition is largely based on any one or a combination of the following factors: functionality and features, price, existing business and customer relationships, product quality, installation capability, service and support, long-term returns, scalability, development and manufacturing capability.

We compete with several companies within the markets that we serve, and we anticipate that competition will intensify. Vendors with which we may compete include: ADTRAN Holdings, Inc.; Ciena Corporation; CommScope Holding Company, Inc.; eero/Ring (Amazon companies); Harmonic Inc.; Huawei Technologies Co., Ltd.; Nokia Corporation; Plume Design, Inc. and Ubiquiti Inc. In various geographic or vertical markets, there are also several smaller companies with which we may compete. As we expand into adjacent markets and expand our platform, cloud and managed services offerings, we expect to encounter new competitors. Many of our competitors have the financial resources to offer competitive products at a below market price, which could prevent us from competing effectively.

Intellectual Property

We rely on a combination of IP rights, including patents, trade secrets, copyrights and trademarks as well as customary contractual protections. These rights and protections are accomplished through a combination of internal and external controls, including contractual protections with employees, contractors, customers and partners, and through a combination of U.S. and international IP laws.

As of December 31, 2025, we held 98 U.S. patents and 90 pending U.S. and international patent applications. U.S. patents generally have a term of twenty years from filing. The remaining terms on our individual patents vary from less than a year to seventeen years. U.S. patent, copyright and trade secret laws afford us only limited protection, and the laws of some foreign countries do not protect proprietary rights to the same extent.

We believe that the frequency of assertions of patent infringement has and continues to increase in our industry. Any claim of infringement from a third party, even claims without merit, could cause us to incur substantial costs defending against such claims, could require us to pay substantial damages or include an injunction or other court order that could prevent us from selling our products. In addition, we might be required to seek a license which may not be available on commercially reasonable terms or at all. Alternatively, we may be required to develop non-infringing technology, which would require significant effort and expense.

Human Capital

We employed 1,921 employees globally as of December 31, 2025 with 1,046 employees located in the U.S. and 875 outside of the U.S., primarily in Canada, China and India. Except for one employee located in France and subject to customary local collective bargaining arrangements, we do not have any employees represented by a labor union with respect to their employment with us. We have not experienced any work stoppages and consider our relations with our employees to be good. We consider our talent to be very important to our operations and execution of our business strategy as well as the overall success of our business. As such, we invest significant management attention, time and resources to attract, engage, develop and retain our talent. Our talent strategy focuses on our culture and core values, our talent programs and the overall well-being and safety of our talent.

8

Table of Contents

Corporate Information

Our principal executive offices are located at: 3155 Olsen Drive, Suite 450, San Jose, California 95117, and our telephone number is (408) 514-3000. Our website address is: www.calix.com. We do not incorporate the information on or accessible through our website into this Annual Report on Form 10-K, and you should not consider any information on, or that can be accessed through, our website as part of this Annual Report on Form 10-K. Calix®, the Calix logo design, AXOS®, Calix Cloud®, CommandIQ®, CommandWorx™, GigaPro®, GigaSpire®, SmartTown® and other trademarks or service marks of Calix appearing in this Annual Report on Form 10-K are the property of Calix. Trade names, trademarks and service marks of other companies appearing in this Annual Report on Form 10-K are the property of the respective holders. The Securities and Exchange Commission (“SEC”) maintains a website at www.sec.gov that contains reports, proxy statements and other information regarding issuers that file electronically with the SEC. We post on the Investor Relations page of our website, www.calix.com, a link to our filings with the SEC free of charge, as soon as reasonably practical after they are filed electronically with the SEC.