S&P 500 and Nasdaq Rally on Cool CPI Report; Nvidia, Palantir, Tesla Bounce

This analysis is based on the Investors.com article [1] published on December 18, 2025, which reported the S&P 500 and Nasdaq Composite rallying on a cool CPI inflation report, with Nvidia (NVDA), Palantir (PLTR), and Tesla (TSLA) bouncing. Initial analysis clarified a critical data interpretation: the “Change” metric in market data refers to intra-day (open-to-close) movement, not daily (previous close-to-current close) performance. Correct daily change calculations show:

• S&P 500: +0.8% (Dec 17 close: 6,721.42 → Dec 18 close: 6,774.75)
• Nasdaq Composite: +1.38% (Dec 17 close: 22,693.32 → Dec 18 close: 23,006.36)
• Palantir (PLTR): +4.74% (Dec 17 close: 177.29 → Dec 18 close: 185.69)
• Tesla (TSLA): +3.45% (Dec 17 close: 467.26 → Dec 18 close: 483.37)
• Nvidia (NVDA): +1.87% (Dec 17 close: 170.94 → Dec 18 close: 174.14)
  These figures confirm the reported rally and bounce, with the Nasdaq leading index gains and Palantir leading stock rebounds from the previous day’s declines. The cool CPI report was identified as the key catalyst [1].

1. Market Sentiment Shift
   : The rally reflects investor optimism that cooling inflation may prompt the Federal Reserve to adopt more accommodative monetary policies, such as rate cuts. This sentiment particularly benefitted growth-oriented sectors like tech, evident in the strong performance of NVDA, PLTR, and TSLA [0].
2. Intra-Day vs Daily Performance
   : The initial data misinterpretation highlights the importance of distinguishing between intra-day volatility and overall daily market direction, a critical consideration for market analysis [0].
3. AI and Tech Stock Sensitivity
   : The bounce in PLTR and NVDA (AI leaders) and TSLA (a tech-focused automaker) underscores their sensitivity to macroeconomic data like CPI, which impacts cost of capital and investor risk appetite [0].

• Risks
  :
  • Potential revisions to the CPI report could reverse market sentiment [1].
  • Other economic indicators (e.g., PPI, unemployment) may conflict with the cool CPI reading, introducing volatility [0].
• Opportunities
  :
  • Sustained cooling inflation could drive further gains in growth stocks, particularly AI-related names [0].
  • The rally may signal a short-term positive momentum shift for U.S. equity markets [0].

On December 18, 2025, the S&P 500 and Nasdaq Composite rallied 0.8% and 1.38%, respectively, following a cooler-than-expected CPI inflation report. Palantir, Tesla, and Nvidia bounced from the previous day’s declines, with Palantir up 4.74%, Tesla up 3.45%, and Nvidia up 1.87%. The rally reflects investor optimism about inflation trends and potential Federal Reserve policy changes, with tech and AI stocks showing strong sensitivity to the macroeconomic catalyst. This analysis provides objective market context without offering investment recommendations.