Measuring exposure from disclosure: Corning and photonics

Corning is best known for glass. Its largest business, by its own reporting, is optical communications: the fibre, cable and connectivity through which telecommunications networks and data centres carry light. This note shows how Corning’s own disclosures establish its membership of our photonics theme, how we measure the share of its revenue the theme accounts for, and why our figure differs from the one Corning publishes.

What the disclosure establishes

Corning reports five segments. Its annual report for fiscal 2025 describes the largest, Optical Communications, as a business that “manufactures carrier network and enterprise network components for the telecommunications industry”. The carrier group serves “optical-based communications infrastructure”; the enterprise group serves networks, “including hyperscale data centers”, that businesses and governments build for their own use.

Under our photonics rule, membership turns on what a company makes and who buys it. Corning makes the hardware through which light is transmitted and connected, and network operators pay it for that hardware. It is a member of the theme. Our record of the decision is dated 31 July 2026 and cites the annual report, published on 12 February 2026.

How much of the business

Membership answers whether a company belongs to a theme; the tier answers how much of the company does. Where a company discloses the revenue of the relevant business, we measure the share directly. In fiscal 2025, Optical Communications generated $6,274 million of Corning’s $15,629 million in consolidated net sales: 40.1%.

That places Corning in the quasi-play tier, which covers companies earning at least 20% but less than 50% of revenue from the theme. Applied to the fiscal 2023 and 2024 figures, the same thresholds give the same tier.

Why our figure differs from Corning’s

Corning’s business description states that Optical Communications “represented 38% of Corning’s total segment net sales in 2025”. Both figures are correct; they use different denominators.

Corning measures segment sales at constant currency. Its total segment net sales of $16,408 million exceed consolidated net sales by $779 million, the effect of constant-currency reporting, which Corning attributes primarily to its Display segment. We divide by consolidated net sales as reported, so that every company’s share is measured against the revenue in its income statement. Because the currency effect falls mainly on Display, the optical numerator is largely unaffected by the choice.

What moved the share

Optical Communications rose from 31.9% of consolidated net sales in fiscal 2023 to 40.1% in fiscal 2025. Enterprise network sales account for $1,869 million, or 83%, of the segment’s $2,262 million increase over the period. Carrier network sales were flat in fiscal 2024 and rose 15% in fiscal 2025.

Corning gives its own explanation in the same report: “the rapid acceleration of artificial intelligence (“AI”) is driving strong demand for fiber and connectivity products inside and between data centers”. For our purposes the cause matters less than the record. The growth is disclosed, dated and attributable to a named product line, and it moves the measured exposure without changing what the company is.

The decision as a record

Every figure in this note comes from one annual report, published on 12 February 2026. Our membership decision is dated 31 July 2026 and uses only disclosures available on that date. When Corning files its next annual report, the share will be measured again. A change of tier would be recorded as a new decision from that date, leaving this one intact.

This note describes how a company is classified. It is not a view on Corning’s shares.

Source

Corning Incorporated, annual report for the fiscal year ended 31 December 2025, published 12 February 2026: the business description and Note 18 (Reportable Segments).