While the artificial intelligence race has focused largely on advanced semiconductors, a slew of mainland China-listed companies produce many of the parts needed to make data centers work. “The United States relies on Chinese firms for almost 30% of its imports of AI-related products,” Michael Hirson and Houze Song at 22V Research wrote in a June 21 report, published in partnership with Analyst Hub Securities. “China lacks the capacity to make advanced chips at scale but plays a central role in the less sexy parts of the data center supply chain, including energy storage, transformers, critical minerals, and chemicals,” the analysts said. “This quiet story is becoming increasingly important for investors to monitor.” AI-related exports have accounted for about half the growth in China’s overall exports this year, the 22V Research report said, noting many of the companies are listed in Shenzhen. Hardware names have driven significant growth in Chinese stocks this year. The ChiNext index that tracks Shenzhen-listed companies has doubled over the last 12 months. The 22V Research report looked at stocks in the CSI 300 index, which covers the largest companies traded in both Shenzhen and Shanghai. Among the 10 biggest AI supply chain companies by market cap, the report found that other than battery giant CATL , the nine other names had all at least doubled in the 12 months as of May. The list included printed circuit board companies such as Nvidia supplier Victory Giant , listed in Shenzhen and Hong Kong , as well Dongshan Precision and Shengyi Technology , both traded in Shenzhen. Sanhuan Group , also traded in Shenzhen, is a manufacturer of multilayer ceramic capacitors, or MLCC , used to store and release energy in chips. Reports indicate Nvidia has nearly tripled the amount of MLCCs included in its latest Vera Rubin AI system. On the server side, Foxconn Industrial Internet , a subsidiary of the Apple iPhone supplier, was another name on 22V’s top 10 list, along with energy company Sungrow Power . Foxconn Industrial Internet said that in 2025, cloud computing surged by 88.7% to 602.68 billion yuan ($88.67 billion), becoming the largest contributor to growth. Three of the companies on the 22V list were optical and networking names: InnoLight , Eoptolink and TFC . Optical technology allows semiconductors to process signals at speeds close to that of light. JPMorgan analysts highlighted the optical fiber component in a June 12 report about China’s AI edge in legacy chips and data center connectivity parts. “Optics is the main ‘picks and shovels’ channel,” the JPMorgan analysts said. “AI data centers require dense, high-speed links and reportedly use 5-10x or even more fiber than traditional server rooms. Some overseas order books now extend into 2027-28, and China Customs data show fiber/cable export value rising to ~4x the year-ago level, with average export prices up ~3x.” While Chinese tech companies generally still trade at lower valuations than their U.S. peers, local investor interest has risen on par. Recent share price gains have propelled InnoLight and Foxconn Industrial Internet into the 1 trillion yuan market cap range, along with CATL. —CNBC’s Michael Bloom contributed to this report.