Google's stock plummets $500 billion as AI search summaries disrupt ad revenue

Google's stock price dropped to a six-month low on October 29, 2026, following the announcement that AI search summaries were significantly impacting ad revenue. The value of the company's shares fell by $500 billion, marking one of the largest single-day declines in its history. The news sent shockwaves through global financial markets, with investors scrambling to reassess the future of Google's core advertising business. The decline was directly linked to the introduction of AI-driven search summaries, which altered how users interacted with search results. Advertisers and publishers feared that the new format would reduce click-through rates and, consequently, ad revenue. The announcement was made by Google itself, confirming the shift in its search algorithm. Financial analysts warned that the change could have long-term implications for the company's profitability and market dominance. Both BBC and British Broadcasting Corporation reported the event with identical headlines and excerpts, indicating a consensus among major global news outlets. No significant divergence in reporting was noted between the sources.