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The bundle of wires that acts as a car’s nervous system, the optical fiber carrying this very web page, and the compound semiconductors behind 5G and radar — a single 125-year-old Japanese company is a global leader in all of them. Sumitomo Electric is one of the quiet pillars of the world’s physical connectivity.
The nervous system of the car
Every vehicle contains a wire harness — kilometres of wiring bundled to carry power and data to every component. Sumitomo Electric is the world’s number-two maker of these harnesses (behind fellow-Japanese Yazaki), making it essential to global auto production. As cars electrify and fill with sensors, the harness grows more complex and more valuable — and Sumitomo is now pioneering automotive optical harnesses to move the huge data volumes that autonomous and high-resolution-sensor cars demand.
The backbone of the internet — and beyond
Sumitomo Electric is also one of the world’s top three makers of optical fiber, the glass threads that carry global internet traffic, and a leader in compound semiconductors such as gallium nitride (GaN) and gallium arsenide (GaAs) substrates used in 5G, radar, and high-frequency electronics. Add power cables, infrastructure, and industrial hard metals, and Sumitomo Electric becomes a remarkably broad supplier of the physical layer of modern connectivity — a cornerstone of the centuries-old Sumitomo group.
Why it matters for global partners and investors
- Investors get exposure to three structural trends at once: vehicle electrification, the data-hungry buildout of networks, and next-generation 5G/radar electronics.
- Automakers and network operators depend on a small group of harness and fiber suppliers; Sumitomo Electric is a central one, with technology that scales as data demand grows.
- The watch item is the shift to optical and high-speed in-vehicle networks, where Sumitomo’s combined wire-and-fiber expertise is a distinctive advantage.
Frequently asked questions
What does Sumitomo Electric make?
It is a global leader in automotive wire harnesses (world #2), optical fiber (top 3), and compound semiconductors (GaN, GaAs), plus power cables and industrial materials. It is a core company of the Sumitomo group.
What is a wire harness, and why does it matter?
A wire harness is the bundled wiring that distributes power and data throughout a vehicle — effectively its nervous system. It grows more complex and valuable as cars electrify and add sensors.
How is Sumitomo Electric tied to the internet?
It is one of the world’s top three makers of optical fiber, the glass cabling that carries the vast majority of global internet and data traffic.
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