Alphabet's worst day in 20 years signals broader AI cost pressures for tech giants

Alphabet shares plunged 12.6% on October 29, marking the company's worst single-day stock decline in over 20 years after reporting its slowest growth, wiping out roughly $500 billion in market value. The drop followed Q3 results showing property and equipment purchases exceeded $51 billion, driving free cash flow negative. Investor concerns center on whether returns from massive AI infrastructure investments can keep pace with escalating costs. Other tech giants face similar pressure. Microsoft, Amazon, Meta, and Oracle are committing billions to AI development, with analysts projecting their combined capital expenditure could outpace free cash flow by 2027. Amazon plans $220 billion in 2026 spending, while Meta raised its outlook to $135-145 billion.