Shares of Jusung Engineering, a little-known industrial equipment maker in South Korea, have soared roughly 80% since mid-April, following reports that it stands to benefit if China restricts exports of solar manufacturing equipment. The stock surge has made Hwang Chul-joo, the company’s founder, chairman and CEO, a billionaire.

With his 26% stake, Hwang, 66, is the largest shareholder of Jusung Engineering, which is listed on South Korea’s technology-rich Kosdaq stock exchange. His wife, Kim Jae-ran, and his son, Eun-seok, hold an additional combined stake of just over 4%. Forbes estimates the net worth of Hwang and his family at $1.1 billion based on Monday’s closing price of 126,600 won.

Based in the city of Gwangju in Gyeonggi province near Seoul, Jusung Engineering makes equipment for mass production of semiconductors, solar cells and advanced digital displays. Its equipment specializes in thin-film deposition, which is the process of coating thin-film (atomic level) layers of chemicals onto a surface, such as a silicon wafer or glass substrate. The thin layers of chemicals help create the electrical circuits within microchips and maximize the light absorption in solar panels (raw silicon reflects some sunlight).

In a report published on April 21, Korea Investment & Securities analyst Chae Min-sook noted that “Jusung Engineering could effectively become the only alternative” should the Chinese government restrict exports of an advanced solar technology known as heterojunction to the U.S. Chae’s observation followed a Reuters report indicating that Chinese officials were mulling export curbs on advanced solar manufacturing equipment, including heterojunction technology, which is essential for producing high-efficiency solar panels.

This would provide a welcome boost to Jusung Engineering’s revenue and net profit, which fell last year due to increased research and development investments. The company reported a 67% drop in net income to 107 billion won on revenue that fell 24% year-over-year to 311 billion won (about $210 million) in 2025. The company draws the bulk of its revenue from the semiconductor business, supplying atomic layer deposition equipment to companies such as memory giant SK Hynix. Jusung Engineering is the world's fourth-largest maker of atomic layer deposition equipment by market share, after ASM International in the Netherlands, Japan’s Tokyo Electron and U.S.-based Lam Research, according to research firm Gartner.

Hwang founded Jusung Engineering in 1993 and listed it in 1999. Previously, he worked at Hyundai Electronics (the predecessor to SK Hynix) and ASM International. He earned a bachelor's degree in electrical engineering from Inha University in Incheon, west of Seoul.

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