Alphabet (GOOGL) is enduring its worst trading day since going public. Driven by its earnings release, the stock fell roughly 12% on Thursday, marking its largest single-day decline since its 2004 listing. The drop erased nearly $500 billion in market value, the second-largest single-day market cap loss in U.S. stock market history.

The all-time record belongs to NVIDIA (NVDA): on January 27, 2025, China's DeepSeek triggered panic among AI investors, wiping out approximately $593 billion in NVIDIA market value in a single day. According to Yahoo Finance calculations, if Alphabet closes at around $274.75, a decline of nearly 15%, it would match NVIDIA's record. It has already surpassed the $400 billion single-day loss record set by SpaceX on June 22, which had previously ranked second in history.

In absolute dollar terms, this is unquestionably Alphabet's most devastating trading day ever. The company's previous largest single-day market cap loss occurred on July 23, at approximately $275 billion. Data from Bespoke Investment on social platforms shows this is also the largest post-earnings decline since Alphabet went public; the previous record was a nearly 10% stock drop in July 2008.

Both bulls and bears have ammunition from this quarterly report: Google Cloud revenue doubled to approximately $31 billion; the Gemini app surpassed 1 billion users. However, search business revenue grew 12% to about $63 billion, below Wall Street's expectation of $65 billion. Due to surging AI investment, free cash flow (cash retained after deducting capital expenditures such as data centers) turned negative, at approximately $9 billion. Massive AI-related costs also weighed on the company's overall performance.

Pivotal Research CEO Jeffrey Wlodarczak said: "The bears will argue that this is the first quarter where AI has genuinely begun to erode the core search business." CFRA analyst Angelo Zino is relatively optimistic, telling Yahoo Finance that this pullback "may be a buying opportunity."

Single-day market cap losses of this magnitude were unheard of in the past. According to Yahoo Finance citing Bloomberg data, as of Wednesday this week, the U.S. stock market has seen 18 instances of single-day market cap losses of $200 billion or more this year; in all of 2025 there were only 13, and before 2022 there were none. Since hitting its stock price peak in May this year, Alphabet alone has lost approximately $1.4 trillion in cumulative market value.

Amazon (AMZN) will release its earnings after Thursday's close, the last of the three major cloud providers to report this week. If Amazon's AWS achieves rapid growth without cash flow being impacted, it would suggest the problem lies with Google's own search business; if Amazon also shows quarterly cash burn, it would cast doubt on the entire AI investment thesis once again.