Apple stock tumbles 8%, erasing $390 billion in market cap in 60 minutes

The Kobeissi Letter post is the direct source of the claim. CNBC's live coverage of Apple's fiscal Q3 2026 earnings independently confirms the core facts: Apple reported weak September-quarter revenue guidance and its stock dropped 8% after hours on July 30, 2026. The $390 billion market-cap loss is arithmetically consistent with an 8% decline from Apple's roughly $4.9-5 trillion valuation (CNBC reported it touched $5 trillion on July 28). All key elements — the 8% figure, the weak-guidance cause, and the ~$390 billion loss — align across sources. The 'in 60 minutes' timing detail is specific to the Kobeissi post and reflects intraday/after-hours volatility, which is plausible but harder to independently verify; this is the only element with minor uncertainty.