$PLANOPTIK (ETR: P4O)
One of the most underestimated bottlenecks in the entire AI hardware supply chain is hidden inside a €50M German micro-cap from a small town in the Westerwald that hardly anyone outside niche investor circles has even heard of.
$PLANOPTIK (ETR: P4O)
The global AI infrastructure buildout is hitting a physical limitation. Traditional organic substrates deform under the immense thermal stress generated by modern AI accelerators consuming up to 1,200 watts per chip. The semiconductor industry’s solution is glass core substrates — a technology that nearly matches silicon’s thermal expansion, reduces warping by over 50%, improves signal integrity by around 40%, and can lower power consumption by as much as 50%. According to SEMI, the glass core substrate market is expected to grow at a 67.2% CAGR between 2028 and 2040.
But inside this market sits an even more critical bottleneck.
To make glass substrates usable, manufacturers must create tens of thousands of microscopic vertical connections known as Through-Glass Vias (TGVs) in ultra-thin glass sheets measuring just 100 micrometers. Existing manufacturing techniques are either too slow, too expensive, or introduce microcracks that eventually cause catastrophic failure under thermal cycling. TGV fabrication has become one of the key constraints in scaling glass substrate production.
PLANOPTIK solved this problem.
Together with 4JET Group, the company developed Volume Laser Induced Structuring (VLIS), a proprietary laser-and-chemical process that locally alters the molecular structure of glass at extremely high speeds without physically removing material. The modified regions are then selectively etched to create perfectly smooth microvias with positional accuracy below 2 micrometers and zero microcracks. The process achieves yields conventional technologies cannot match. While traditional methods are limited to substrate sizes below 200mm, PLANOPTIK can process panels up to 1,500 x 800mm.
And there is a second bottleneck: Optical Circuit Switching packaging.
Google’s TPU v4 and v5 systems rely on Optical Circuit Switching (OCS), where MEMS mirror arrays redirect infrared laser beams between massive GPU clusters. These systems require hermetically sealed micro-structured glass packaging with optical-grade glass caps that allow laser transmission without distortion. PLANOPTIK is the sole supplier of these specialized glass packaging wafers to Silex Microsystems — the world’s largest pure-play MEMS foundry — as well as Teledyne DALSA. Its headquarters is also located directly next to optical coating specialist BTE Born, creating a tightly integrated manufacturing ecosystem that is difficult for competitors to replicate.
So why do the financials currently look weak?
2025 was hit by two simultaneous one-off effects. Major customers reduced inventory levels over an extended period while management simultaneously transitioned from German GAAP to IFRS and upgraded the company from the Frankfurt Open Market to the Regulated Market General Standard. The associated compliance costs were substantial and heavily concentrated in 2025.
On a normalized basis using 2023 peak figures, the company generated:
• €13.25M revenue
• €3.07M EBITDA
• €1.67M net profit
• 88% gross margin
The restructuring phase is complete. Inventory destocking has ended. Management guided for revenue growth exceeding €1M in 2026 and expects a significantly stronger acceleration in 2027 as several customers move into full-scale production.
Balance sheet:
• €3.73M cash
• €19M total assets
• only €6M liabilities
• 68% equity ratio
• zero debt
• Altman Z-Score of 7.72, indicating extremely low insolvency risk
Current valuation: around €50M market cap with only 0.44% institutional ownership.
Following the Regulated Market upgrade, the stock has become investable for European mutual funds and ETFs for the first time.
An 88% gross margin.
Zero debt.
A proprietary TGV manufacturing process with no credible competitor.
And sole-supplier positioning in OCS glass packaging for leading MEMS foundries.
The glass core substrate market is projected to grow at a 67.2% CAGR starting in 2028. Advanced semiconductor packaging is expected to expand from $44B to $87B by 2035.
PLANOPTIK sits directly at the center of both trends.
The market still hasn’t noticed.
$P4O
Posted May 28, 2026, 10:48 AM UTC