Soitec: Photonics-SOI Growth Approaching 70% Remains Underpriced
Soitec’s 4Q26 beat and better-than-feared F1Q27 guidance obscure a more important development: Photonics‑SOI is growing far faster than the official disclosure implies. Our back‑calculation points to FY26 growth of 60–70% to roughly $130m, well beyond the company’s stated “above $100m.” With management confirming accelerating momentum and the mobilization of industrial capacity, photonics is becoming the hidden growth engine that solidifies the medium‑term investment case—even as Mobile Communications remains a drag.
What the Market May Be Underestimating
The true trajectory of Photonics‑SOI is masked because Soitec reports it jointly with FD‑SOI, disclosing combined growth of 25% ex‑FX. Assuming a realistic 5–10% expansion for FD‑SOI (versus our earlier expectation of a 7% decline), we derive 60–70% Photonics‑SOI growth to ~$130m. This is significantly ahead of sell‑side models that had pencilled in about 45% ($112m). The gap between “>$100m” and the implied ~$130m suggests management conservatism is hiding an explosive ramp. The market has yet to price the divergence.
Evidence for an Accelerating Engine
The 4Q26 revenue beat of €200m was powered by unexpected seasonal strength in Automotive & Industrial, which more than offset weaker Mobile Communications. That diversification confirms the company’s capacity to capture secular demand beyond smartphones. Moreover, the F1Q27 guidance of +15% y/y—though partly attributable to reduced seasonality—exceeded fears of a steeper slowdown. Management explicitly highlighted accelerating Photonics‑SOI momentum and the mobilization of its industrial footprint to meet growing customer demand. These data points support the thesis that the photonics inflection is underway now, not just a CY28 story. The near‑term cushion from automotive and industrial outperformance limits downside risk while the structural driver gains scale.
Key Risks
The back‑calculation hinges on FD‑SOI growing 5–10%; a flat FD‑SOI performance would imply lower Photonics‑SOI growth, albeit still rapid. Mobile Communications weakness could persist as a headwind if design activity fails to recover. The F1Q27 guide partly reflects phasing shifts; if end‑demand disappoints, subsequent quarters may face downward revisions. Lastly, execution in scaling photonics capacity remains a critical variable—the “mobilization” language is encouraging but still at an early stage.
Valuation and Trading Implications
Current valuation likely embeds a photonics trajectory that underestimates a 60–70% growth run‑rate. Should the upcoming analyst day deliver a more ambitious medium‑term outlook—particularly around CY28 revenue acceleration—the shares could re‑rate. We would use any pullback tied to Mobile‑related concerns to accumulate, focusing on the credibility and pace of the photonics ramp. The risk‑reward is asymmetric: short‑term weakness from mobile worries creates entry points into a multi‑year secular theme that is only beginning to be recognized.