HLIT · CIK 0000851310
What Harmonic Inc. told the SEC could break it.
Harmonic's disclosures show concentration at both ends of its business. Its revenue leans heavily on a single customer, which was 54% of total net revenue in 2025 (one customer was 64% in 2023), so reduced orders there would materially hurt results. Its supply chain is similarly narrow: many components and subassemblies come from a single source or a limited group of suppliers, with few viable second sources. Compounding that, critical functions are concentrated in volatile regions — about 37% of its workforce (200 employees) is in Israel performing R&D and supply-chain work, with additional outsourced engineering in Ukraine — and U.S. tariffs have already moderately raised its costs on imported products and components.
4 self-disclosed vulnerabilities, pulled from its own filings, each in the company’s words, with the source. This is the risk register almost nobody reads.
In its own words
What could break it.
Customer concentration
- single largest customer (~54% of net revenue)high
Harmonic's revenue is extremely concentrated: one customer accounted for 54% of total net revenue in 2025 (one customer was 64% in 2023; two were 57% and 24% in 2024). The customer is not named in the filing. Loss of or reduced orders from this customer would materially harm results.
“One customer accounted for 54 % of the Company's total net revenues during the years ended December 31, 2025. Two customers accounted for 57 % and 24 % of the Company's total net revenues during the year ended December 31, 2024, respectively. One customer accounted for 64 % of the Company's total net revenues during the years ended December 31, 2023.”
SEC filing →As of 2026
Sole-source dependency
- single/limited-source components and subassemblieshigh
Many components, subassemblies and modules used in Harmonic's products are obtained from a single source or a limited group of suppliers; consolidation of suppliers and few viable alternatives limit second-sourcing efforts, so loss of these sources could adversely affect operations and damage customer relationships.
“Certain of the components and subassemblies included in the Company's products are obtained from a single source or a limited group of suppliers. Although the Company seeks to reduce dependence on those sole source and limited source suppliers, the partial or complete loss of certain of these sources could have at least a temporary adverse effect on the Company's results of operations and damage customer relationships.”
SEC filing →As of 2026
Geographic concentration
- Israel operations / Ukraine outsourced engineeringmedium
Approximately 37% of Harmonic's worldwide workforce (200 employees) is located in Israel, performing R&D, product development, product management and supply-chain activities; it also relies on outsourced engineering resources in Ukraine — concentrating critical functions in geopolitically volatile regions.
“We face risks associated with having facilities and employees located in Israel. As of December 31, 2025, we maintained facilities in Israel with a total of 200 employees, or approximately 37% of our worldwide workforce.”
Regulatory & policy
- U.S. tariffs on imported products and componentsmedium
Harmonic experienced a moderate increase in tariff-related costs in fiscal 2025 from U.S. tariff policies; further tariff increases on imported products/components (including from sole/limited suppliers and its Malaysia-based contract manufacturer Plexus) that it cannot mitigate could raise costs, reduce revenue or force price increases.
“During the fiscal year 2025, we experienced a moderate increase in tariff-related costs due to U.S. tariff policies.”
The hidden graph
Who it depends on, and who depends on it.
Relationships surfaced from filings, including ones disclosed by the other side, which is how the non-obvious ones come to light.
Its customers
Millicom International Cellular S.A.
“we rely on a limited number of manufacturers to provide network and telecommunications equipment and technical support. The key suppliers of equipment and software for our existing networks are Huawei, Ericsson, Nokia, PPC, Fiberhome, Harmonic, Kaon, Vantiva, Juniper, Intraway and VMWare.”
Cited →
Its suppliers
“Plexus Services Corp. (“Plexus”), which manufactures our products at its facilities in Malaysia, currently serves as our primary contract manufacturer”
Cited →
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