S&P 500 Gains and Losses Today: Palantir Plunges; Health Insurance Stocks Surge
1. Humana shares soared nearly 11% after positive Medicare Advantage outlook. 2. Company's quality ratings update boosted market confidence and stock performance. 3. Humana led S&P 500 with top performance amidst mixed market conditions. 4. Centene and Cigna shares also rose following Humana's announcements. 5. Palantir Technologies experienced a significant decline due to security concerns.