FormFactor stock (ISIN US3463751087) closed at USD 118.38 on Nasdaq on September 18, 2026, up 6.14% on the day, as investors continued to price in strong demand for AI-related semiconductor testing equipment. According to MarketBeat data as of September 18, 2026, shares have risen 112.2% since the beginning of 2026, from USD 55.78 at the start of the year, on accelerating adoption of AI infrastructure in data centers. FormFactor designs and supplies probe cards and test systems used in semiconductor manufacturing, tying its business to capital spending on advanced chips. A September 21, 2026 analysis noted the company plugs into the AI-exposed semiconductor supply chain by providing test gear chipmakers rely on before wafers leave the fabrication plant, with demand driven by generative AI, high-performance computing and high-bandwidth memory in data centers, according to Yahoo Finance on September 21, 2026. The same article highlighted that accelerating adoption of generative AI, high-performance computing and HBM DRAM is driving substantial increases in test complexity and intensity, and that FormFactor’s differentiated probe cards and early leadership in HBM4 chiplet testing position it to benefit from higher average selling prices and revenue growth as these markets scale. Yahoo Finance data showed after-hours trading at USD 117.50 the same evening.