**What happened: **Semiconductor stocks rallied on Tuesday, with the PHLX Semiconductor Index (SOXX) surging over 6%, helping send the S&P 500 (^GSPC) to new highs.
US-listed shares of memory and storage leaders Micron Technology (MU) and SK Hynix (SKHY) jumped 8% and 6%, respectively. Shares of Marvell Technology (MRVL) also rallied 14%.
AI chip heavyweight Nvidia (NVDA) gained nearly 2%, while shares of AMD (AMD) jumped 7% ahead of the company's quarterly results. Chipmaker Intel (INTC) rose 10%.
What's behind the move: Marvell Technology launched the Flash Memory Summit 2026 in California on Tuesday, introducing new AI-optimized memory and storage infrastructure products to meet growing compute demands of agentic AI inference.
Investors also awaited results from AMD, which reports after the close on Tuesday. Market watchers were expecting explosive moves either to the upside or the downside.
"AMD — this is a company that tends to be so good at guiding the Street," Cboe senior vice president JJ Kinahan told Yahoo Finance on Monday.
"They have been within a penny for the last 12 earnings reports in terms of where they are going to be. However, on more than half of them, they actually sold off afterward," he noted.
**What else you need to know: **The semiconductor index led market gains on Tuesday as the S&P 500 and the Dow Jones Industrial Average (DJI) both headed toward record closes. The rally follows a volatile stretch for AI infrastructure stocks, driven by concerns about overinvestment and intensifying competition from China.
Semiconductor stocks have been at the center of the AI trade this year but tumbled from record highs into bear-market territory last month, dropping more than 20% from their highs as investors grow increasingly concerned about hyperscalers' massive AI spending spree.
Worries about China's advancement in AI, driven by less expensive models, have also weighed on the AI infrastructure trade.
Ines Ferre is a senior business reporter for Yahoo Finance. Follow her on X at @ines_ferre.
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