Big Tech's $720B AI spending spree spooks investors

What happened

Alphabet, Amazon, Meta Platforms, and Microsoft plan to spend up to $720 billion（約120兆円） this year on AI data centers. This week, investors have grown skeptical — Amazon and Alphabet each fell about 5% on Monday, and on Tuesday chip makers Nvidia, Micron Technology, Broadcom, and Lam Research led the market lower. Alphabet is raising $80 billion（約13兆円） by selling stock and planning to spend as much as $190 billion（約30兆円） this year, while Amazon sold $54 billion（約8.6兆円） of bonds and plans to spend around $200 billion（約32兆円） on AI investments.

Why it matters

For months, investors eagerly bought into the AI investment story. Now they're asking whether these enormous outlays will generate enough profit and productivity to justify the cost — a sign that confidence in the AI boom may be waning. The concern echoes long-standing criticism about a potential bubble in AI investment spending.

What to watch

Chip stocks are particularly exposed to the pullback, since they've soared on expectations of rising AI data center demand. For example, Marvell Technologies' stock has more than tripled year to date and its price-to-earnings ratio has climbed to near 100, while Sandisk shares have soared more than 700% year to date with a P/E ratio of 68 — valuations that leave little room for disappointment if AI spending slows.