Google's parent company Alphabet has suffered its biggest stock market wipeout ever after investors took fright from its latest earnings report.

Shares plunged almost 13 percent on Thursday, wiping an astonishing $482 billion off its market value in a single trading session.

It was the steepest one-day percentage decline in the company's history since its 2004 stock market debut, eclipsing even the turmoil of the 2008 financial crisis and the Covid crash of 2020.

The loss marked the second-largest single-day destruction of market value ever recorded by a US-listed company, surpassed only by Nvidia's $593 billion wipeout in January 2025, when Chinese AI startup DeepSeek rattled the technology sector.

For Alphabet, the latest rout also dwarfed its previous biggest one-day market-value loss of around $275 billion, back in July.

The brutal sell-off came despite some eye-catching figures in the company's third-quarter results, underlining just how high expectations have become in the race to dominate artificial intelligence.

Google Cloud was a standout performer, with revenue more than doubling to around $31 billion as businesses continued snapping up AI computing power.

But the company's bread-and-butter search business offered less cause for celebration, with revenue rising 12 percent to around $63 billion – falling short of Wall Street's expectations of approximately $65 billion.

Investors were also disappointed by the company's overall financial performance, with the results raising questions about whether its enormous AI investments will deliver the returns shareholders are expecting.

That is an awkward position for a company whose search engine has long been treated as a money-printing machine, particularly as users increasingly experiment with AI-powered ways of finding information.

Investors are now asking whether Google's costly AI push could end up eating into the very search business that has financed its growth for years.

Pivotal Research chief executive Jeffrey Wlodarczak said bearish investors could argue that this was the first quarter in which AI was starting to seriously hurt Google's search operation.