US AI stock sell-off shakes markets from Wall Street to Asia

• Seven tech companies now comprise 30% of the S&P 500's value, with analysts warning AI-related borrowing could surpass $500bn this year as companies increasingly finance spending through debt
• Asian markets were hit hard, with South Korea's benchmark falling 10% and major chipmakers SK Hynix and Samsung Electronics both down over 12%, while Japan's Nikkei 225 dropped 3.5%
• SpaceX announced plans to raise $20bn through a bond sale despite gaining over $85bn from its recent IPO, intensifying concerns about excessive AI infrastructure spending by Big Tech

Summary: US AI Stock Sell-Off Shakes Global Markets

Market Performance:

A significant tech sell-off rattled global markets on Tuesday, June 22, 2026, as investor concerns mounted over AI valuations and infrastructure spending. The Nasdaq opened 2% lower, while the Dow and S&P 500 also declined at opening. Despite the sell-off, major indices remain positive year-to-date: Nasdaq up 10%, Dow up 6% (breaching 51,000 points), and S&P 500 up 7.3%.

Key Concerns:

Economists warn of a potential bubble reminiscent of the dot-com crash, with seven tech companies comprising 30% of the S&P 500's value. The Federal Reserve's signals of potential rate hikes to combat inflation have heightened investor anxiety about borrowing costs.

Company-Specific Developments:

• Alphabet (Google): Experienced its worst trading day in over a year following the departure of two high-profile AI researchers
• SpaceX: Dropped 16% on Monday after announcing plans to raise $20 billion through bond sales, despite gaining over $85 billion from its June 12 IPO

Global Impact:

Asian markets suffered significant losses. South Korea's benchmark index fell 10%, with chipmakers SK Hynix and Samsung Electronics both down over 12%. Japan's Nikkei 225 declined 3.5%.

Industry Analysis:

Morgan Stanley estimates AI-related borrowing will exceed $500 billion this year. Analysts express concern that Big Tech companies are overspending on AI infrastructure while increasingly relying on debt financing to fund these projects.