Investopediaยท2025-09-22 21:20Core Insights - Nvidia's investment of up to $100 million in OpenAI has boosted optimism in the artificial intelligence sector, contributing to record highs in major U.S. equity indexes [3][7] - Teradyne's shares surged 13% following a price target increase by Susquehanna Financial, driven by strong demand trends and partnerships with Taiwan Semiconductor Manufacturing Company [4][8] - Oracle's shares rose 6.3% after being confirmed as part of a consortium to control TikTok's U.S. operations, alongside leadership changes within the company [5] - Moderna's shares increased by 5.2% after the CDC's vaccine panel updated its recommendations regarding COVID vaccinations [6] - Kenvue's shares dropped 7.5% due to reports linking Tylenol use during pregnancy to autism, despite the company asserting no scientific link [10] - Westinghouse Air Brake Technologies (WAB) shares rose 4.9% following a $4 billion deal to supply locomotives to Kazakhstan's national railway [9] Company-Specific Developments - Nvidia's stock rose 4% as it announced plans to invest significantly in AI, reflecting a broader trend of tech stocks performing well [3] - Teradyne's strong performance is attributed to its role in semiconductor testing and partnerships with major industry players [4] - Oracle's leadership transition to co-CEOs and its involvement with TikTok has positively impacted its stock performance [5] - Moderna's stock gain is linked to the CDC's revised guidance on COVID vaccinations, indicating a potential shift in public health policy [6] - Kenvue's stock decline highlights the impact of regulatory announcements on consumer health companies [10] - WAB's contract for locomotives indicates a positive outlook for the rail equipment sector amid increasing infrastructure investments [9]