Alphabet Sheds $500 Billion in a Single Day Despite Cloud Growth of 103%

When headlines scream that a stock had its "worst day ever," it's often an exaggeration. But that wasn't the case for Google parent Alphabet (NASDAQ:GOOG) (NASDAQ:GOOGL) today.

Alphabet did, in fact, have its worst day ever today. It dropped over 13% after reporting Q3 results. That's its biggest share price drop – in both percentage and absolute dollars – since the company went public in 2004.

In terms of market capitalization, Alphabet is now worth $482 billion less than it was this morning. That's the second-largest one-day market cap drop in U.S. history. Nvidia's (NASDAQ:NVDA) $593 billion DeepSeek-related drop from January 2025 still holds the top spot.

Ouch.

So, how horrible were Alphabet's quarterly results to prompt this kind of sell-off?

That's the thing: they weren't that bad. Revenue and operating income soared. But there was one big number that overshadowed everything, and it's the one that mattered most to Wall Street.

Here's why the market just handed Google's parent its worst day ever, and why there might be more bad days to come for Alphabet investors.

Image source: The Motley Fool.

Record revenue meets record spending

Alphabet's quarterly revenue of $127.6 billion was a 25% increase from the prior-year quarter. This was primarily driven by a surge in Google Cloud revenues, which jumped 103% year-over-year, from $15.2 billion to $30.7 billion. According to the company, that massive increase was driven by "huge demand for... AI infrastructure and AI solutions."

Google search revenue – the company's largest revenue category – also grew, but by a lower-than-expected 12%, to $63.4 billion. That represented a slowdown from the 17% growth it saw in Q2.

That revenue gain translated to a 30% increase in operating income, thanks to an operating margin of 31.8%, up slightly from the prior year's 31%. In other words, Alphabet is making more money more efficiently.

But unfortunately for Alphabet, operating income isn't net income, and it was on the bottom line where the company ran into problems.

In Q3 2025, the company's operating income of $31.2 billion was boosted by $12.8 billion in "other income," resulting in $44 billion in earnings before taxes. This year, it was almost the reverse. Alphabet's $40.6 billion in operating income saw an $8.2 billion net decline from "other expenses," resulting in $32.4 billion of income before taxes.

That meant the bottom line was just $26.2 billion in net income, down 25% from the prior-year quarter. When you factor in the company's issuance of 36 million new shares of stock during the quarter, diluted earnings per share were just $2.12, down 26% from Q3 2025.

And you can probably guess what those "other expenses" were.

Image source: Getty Images.

It's all about AI

If you guessed AI spending, you're right!

Alphabet's capital expenditures jumped to a record $51.4 billion from $24 billion in the year-ago quarter. That was even more than the $44.9 billion it spent in Q2. As a result, it recorded its second consecutive quarter of negative free cash flow, at $9.1 billion.

The moral of the story is that AI is proving to be a double-edged sword for Google.

On the one hand, it's driving huge growth in both revenue and net income from Google Cloud, resulting in record revenue and strong growth in operating income.

On the other hand, it's costing a fortune, and right now the enormous upfront expenses are outweighing the gains. The slowing growth in Google Search revenue also raises concerns that AI agents are eroding Google Search's dominance, which could turn AI into a net negative revenue driver for the company if the trend continues.

Although rising capex, a decline in profits, and two consecutive quarters of negative cash flow aren't good, investors should remember that, at least as of now, this is still a short-term problem. If Alphabet can continue growing Google Cloud revenue and figure out how to monetize the growing number of AI searches on its platform, it could easily come out a winner.

But it's likely to take some time before that becomes clear, and in the meantime, nervous investors may not be willing to give the free-cash-flow-negative Alphabet the benefit of the doubt.

While another 13% one-day drop seems unlikely, there may be many more rough days in Alphabet's near-term future.

John Bromels has positions in Alphabet and Nvidia. The Motley Fool has positions in and recommends Alphabet and Nvidia. The Motley Fool has a disclosure policy.