Meta's AI agent, Muse, reached a peak of 448,000 daily active users and a record 264,000 single-day downloads just 12 days after its launch, significantly outperforming ChatGPT's initial period. This has fueled market speculation that consumer-grade AI is entering a mainstream inflection point. Boosted by this, the Nasdaq 100 closed up approximately 2.83% on September 21, surpassing 30,000 points and reaching a new high since June. However, Goldman Sachs analyst Peter Callahan described it as a "quiet surge," with trading activity at only 3 out of 10, and gains highly concentrated in large-cap tech stocks. CPU chip stocks Arm Holdings, Intel, and AMD rose over 15%, 12%, and 10% respectively on the day, with AMD's market capitalization reaching $1 trillion for the first time. Meanwhile, a divergence emerged between the credit market and the stock market, as investment-grade CDS spreads widened to a five-month high, indicating market reservations about the current optimistic sentiment. Micron's earnings report next week will be a critical validation point for the sustainability of AI infrastructure trading.