Why Is Arm Holdings (ARM) Stock Price Up 17.16% Today, Sep 21? Meta Muse AI Demand and $2B CPU Pipeline Lift ARM

Arm surged on reports that rapid adoption of Meta's Muse AI agent is lifting expectations for CPU-heavy inference demand, with Arm's cited $2B+ AGI CPU pipeline reinforcing company-specific upside. The move also coincided with a broad semiconductor rally, signaling renewed risk appetite in AI compute. Near-term focus shifts to whether gains hold after a sharp repricing and whether demand converts into shipments amid capacity constraints.