Teradyne Inc. stock advanced roughly 5 percent on September 18, 2026, as investors responded to robust AI chip testing demand and the company’s recent expansion in India, with Nasdaq-listed shares closing around USD 371 and pushing market capitalization above USD 58 billion. According to MarketBeat, shares closed at USD 371.47 on Nasdaq, up USD 18.34 or 5.19 percent on the day, while extended trading later showed a slight pullback to USD 369.68. The 52-week range spans from USD 117.54 to USD 487.91, and market capitalization stood at USD 58.08 billion, with daily volume around 4.29 million shares versus an average of 2.30 million. Shares traded at USD 193.56 at the start of 2026 and have since risen to USD 371.47, a gain of approximately 91.9 percent year to date. Investing.com reported that director Marilyn Matz sold 400 shares on September 17, 2026, at USD 351.11 per share, for total proceeds of USD 140,444. MarketBeat notes a price-to-earnings ratio of 50.96 and a dividend yield of 0.14 percent. Zacks reported the consensus estimate for earnings per share in the quarter ending September 2026 stands at USD 2.03.