Alphabet Plunges 13% in Worst Day Ever, Erasing About $500B as AI Spending Turns Cash Flow Negative

Alphabet (GOOGL) shares plunged about 13% on Oct. 29, the stock's worst day on record, erasing roughly $500 billion in market value after record AI spending pushed third-quarter free cash flow to negative $9.1 billion and Google acknowledged that AI-powered searches generate less advertising revenue. Search revenue grew 12%, slowing from nearly 20% earlier this year, while profit missed estimates. The Nasdaq fell about 1.4%. If sustained, the loss would be Wall Street's second-largest single-day market-value decline, behind Nvidia's roughly $593 billion drop in January 2025.

Where the quarter fell short

Net income included $8.7 billion in losses on equity investments, partly tied to Alphabet's stake in SpaceX, which is separate from operating performance.

AI Mode earns less than classic search

Google confirmed that its conversational AI Mode generates lower ad monetization than traditional search, which weighed on search growth this quarter. Management said most AI Mode queries are incremental and could create monetization opportunities over time, and it is expanding ads in AI Overviews and AI Mode, including multi-turn ads in the U.S. and more international markets. The concern is that growth in AI-driven searches may not carry the same revenue per query as the business it is changing.

Spending that outruns cash flow

Capital spending rose to $51.4 billion from $44.9 billion in the second quarter, and operating cash flow of $42.3 billion fell 13%, leaving free cash flow negative. Alphabet kept its 2026 capex guidance at up to $205 billion, which implies as much as roughly $73 billion in the fourth quarter, and said spending will rise significantly in 2027. Future data center, equipment, energy and lease commitments reportedly exceed $1 trillion. Cloud backlog reached $561 billion. For more on the cloud side of the story, see our Alphabet cloud article.

How Alphabet is paying for it

Long-term debt rose to $125.1 billion from $46.5 billion at the end of 2025, including $28.7 billion of senior notes raised in the quarter. Alphabet also sold about $12.4 billion of stock through an at-the-market program, with roughly $27.6 billion still available, as part of an equity financing of about $85 billion announced in June. It made no share repurchases in the quarter, compared with $11.5 billion a year earlier, and held $265.1 billion in cash and marketable securities.

A record single-day loss for Alphabet

The roughly $500 billion decline, which reached about $524 billion at the intraday low, is nearly double Alphabet's previous worst single-day loss of about $275 billion. Shares traded near $284. Investors are weighing how much AI infrastructure spending is needed before it earns an adequate return. Microsoft spent $45.2 billion on capex while generating $18.6 billion in free cash flow, which highlights the growing focus on investment returns.

Sources: Alphabet's third-quarter 2026 results and earnings call remarks; analyst estimates, share-price moves and market-value figures are from market data. This is informational, not a recommendation to buy or sell.