Why Is Astera Labs (ALAB) Stock Up 9.75% Today, Sep 4? AI-Infrastructure Semiconductor Rally Sparks Rebound

Astera Labs rallied ~9.75% amid a broad AI-infrastructure semiconductor rebound and speculation around potential S\u0026P 500 inclusion, which can drive incremental index-tracking flows. The move appears more sector and positioning-driven than tied to new company fundamentals, raising sensitivity to post-rebalance outcomes and follow-through in hyperscaler capex and AI-server connectivity orders. Near-term trading is likely to hinge on whether the inclusion catalyst materializes and sector strength persists.