Direct Answer
Lumentum reports revenue across 2 business segments in its fiscal 2025 Form 10-K. Cloud Networking is the largest, with $1.4 billion of revenue (86% of the total), followed by Industrial Technology at $234 million (14%).
How Does Lumentum Make Money?
Cloud Networking supplies 86% of revenue, so Lumentum's results move mostly with that one business; the others matter more for diversification than for the headline number. Between fiscal 2024 and 2025, Cloud Networking grew fastest (+30.0%) and Industrial Technology slowest (-14.6%), so the revenue mix tilts toward Cloud Networking while that gap lasts.
| Segment | FY2025 revenue | FY2024 revenue | Share of revenue | Change |
|---|---|---|---|---|
| Cloud Networking | $1.4 billion | $1.1 billion | 85.8% | 30.0% |
| Industrial Technology | $234 million | $274 million | 14.2% | -14.6% |
What the Segment Figures Do Not Show
The rows above add up to 100% of Lumentum's reported revenue for fiscal 2025; the difference is intersegment eliminations, corporate revenue or items the company reports outside its segments. Segment definitions are management's choice and change when a company reorganizes, in which case it restates prior years in the next filing, so a multi-year comparison should use the figures from a single filing. Revenue shows where sales come from, not where profit or cash is earned: a small segment can carry most of the margin.
Where These Numbers Come From
Every figure on this page is a value Lumentum reported in the segment note and revenue disclosures of its Form 10-K filed August 19, 2025 (accession 0001628280-25-040830), read from the SEC's Financial Statement Data Sets. The prior-year column is the comparative figure from that same filing, so it reflects any restatement for a change in segments. Category names are the company's own XBRL labels, lightly reformatted for reading.
Rows that only total other rows (for example a "Products" line beside the individual products) are left out so nothing is counted twice. This page is educational and describes reported history for fiscal 2025; it is not a forecast or a recommendation.
Frequently Asked Questions
What are Lumentum's business segments?
In its fiscal 2025 Form 10-K, Lumentum reports revenue for Cloud Networking and Industrial Technology.
Which part of Lumentum brings in the most revenue?
Cloud Networking, with $1.4 billion of revenue in fiscal 2025, or 86% of the total.
Where does Lumentum report its segment results?
In the segment note to the financial statements in its Form 10-K, most recently filed August 17, 2026, alongside management's discussion of each segment's results.