Alphabet loses nearly $500 billion in market value in record plunge Shares of Alphabet, the parent company of Google, plunged 12.63% on Thursday, wiping out nearly $500 billion in market value - the sharpest one-day drop since it went public in 2004. The sell-off reflects growing investor concerns about AI-driven disruption, AI investment booms and uncertain returns. AI disruption is real. The risks of circular investment and financial dependence between AI companies are also real.