These Were the S&P 500’s Best and Worst Stocks in October
1. Fiserv's shares plummeted nearly 48.9% after a dismal earnings outlook. 2. Advanced Micro Devices soared 61.6% due to a significant contract with OpenAI. 3. AI-related stocks performed exceptionally well, leading S&P 500's top gains this month. 4. Many companies experienced poor performance, including Alexandria Real Estate and Molina Healthcare. 5. October marked a month of transformative trades and earnings in tech sector.