A Taiwanese parts maker has become one of the biggest winners of the AI boom without touching chips, but its dominance may be harder to hold next year.

• King Slide Works makes the sliding rails that hold heavy AI servers in racks, and controls about 80% of the high-end market.
• Its stock is up nearly 280% this year, making founder Lin Tsung-chi Taiwan's richest person, ahead of Foxconn's Terry Gou.
• Profit margins are extraordinary for a hardware company — higher than Nvidia's or TSMC's — which the company credits to two decades of engineering work.
• New server designs using custom chips and liquid cooling need specially built rails, pushing prices up and expanding the business; a Texas plant is being expanded to serve US customers.
• Nvidia is spreading orders to more suppliers, and King Slide's share of that business could slip next year as cloud giants use rival vendors to push prices down.

Outlook: Demand should stay strong as data centers keep going up, but competition and price pressure are likely to bite into those unusually fat margins.