Nvidia's stock climbed 2.3% Wednesday, marking its sixth straight gain and fueling fresh records for the S&P 500 and Nasdaq. The surge came as CEO Jensen Huang joined a high-stakes China summit, underscoring the chip maker's central role in the global AI race. In intraday trading, Nvidia became the first company to reach a market capitalization of $5.5 trillion.

This rally extends a blistering run that has made Nvidia the market's dominant force. The company's performance now carries significant weight for major indexes, with its advances repeatedly lifting broad market benchmarks. Huang's presence at the China meeting highlights how Nvidia's technology sits at the heart of geopolitical tensions over artificial intelligence and semiconductor supply chains.

The stock's sustained climb reflects intense investor confidence in Nvidia's AI infrastructure leadership. Its market cap milestone signals unprecedented valuation, driven by expectations for continued dominance in AI chips. This concentration of market power in a single tech stock presents both opportunity and risk for index investors tied to its trajectory.