Alphabet's (GOOGL) stock experienced a notable decline on Tuesday, October 21, 2025, after OpenAI announced the launch of its new AI-powered web browser, 'ChatGPT Atlas'. Shares of the tech giant fell as much as 4% following the news, which investors see as a significant competitive threat to Google's dominant Chrome browser and its lucrative search advertising business. The new browser from OpenAI is designed to integrate advanced AI capabilities directly into the user's web experience, potentially altering how users search for information online. The market's reaction reflects concerns that a powerful new entrant in the browser space, backed by OpenAI's AI prowess, could disrupt Google's long-standing dominance and impact its primary revenue streams. The move intensifies the ongoing AI rivalry between the two technology giants.