US Tech Stocks Plunge Amid AI Infrastructure Investment Concerns: Alphabet and Nvidia Sell-off Analysis

Nasdaq Plunges Over 2%, Signaling Tech Sector Correction

On July 24, 2026, global markets entered a distinct correction phase driven primarily by large-cap technology stocks. The Nasdaq index dropped over 2% overnight, reflecting a sharp contraction in investor sentiment. This downward trend was led by key artificial intelligence (AI) companies that had previously fueled the market rally on the front lines. The price action in Alphabet (Google) and Nvidia, in particular, strongly suggests that the market is beginning to apply new, rigorous metrics to the practical profitability and capital efficiency of the AI industry. We are entering an environment where mere expectations of future growth are no longer sufficient to justify current high valuations.

Alphabet's Earnings and the AI CapEx Dilemma

One of the core triggers for this tech weakness was Alphabet's second-quarter earnings report and its accompanying massive capital expenditure (CapEx) figures. Despite reporting solid revenue that exceeded market consensus, Alphabet's stock price failed to avoid a downward trajectory. Market concerns were heavily focused on the staggering costs associated with AI infrastructure investments rather than cloud growth.

Currently, major big tech companies are pouring astronomical amounts of capital into advancing generative AI models and expanding data centers. However, this competitive investment is leading to near-term weakness in free cash flow (FCF), and investors are increasingly questioning when these substantial capital expenditures will be recouped through meaningful profit growth. The sell-off reflects growing concerns that the monetization of actual services may be delayed relative to the capital deployed for AI infrastructure.

Nvidia and Concerns Over Slowing AI Chip Demand

Nvidia, widely considered the largest beneficiary of AI infrastructure spending, also faced intense downward pressure. Doubts about the sustainability of preemptive infrastructure investments by big tech companies like Alphabet naturally translated into concerns about a potential slowdown in demand for core AI chips. The stock's rapid surge over recent months, backed by strong earnings, had pushed valuation burdens to an extreme, prompting massive profit-taking led by institutional investors.

Given the market's high concentration and dependence on a single company, Nvidia's stock price volatility triggered a chain reaction that instantly dragged down investor sentiment across the entire technology sector. Market participants are now moving beyond simple growth expectations and demanding structural, continuous proof that hardware-centric investment expansion will translate into actual software and cloud service revenues.

Ripple Effects on the Domestic Market: Concurrent Drops in Semiconductors and KOSPI

The weakness in US tech stocks had an immediate and direct impact on the domestic market. Foreign and institutional selling heavily concentrated on large-cap semiconductor stocks such as SK Hynix and Samsung Electronics, which form a core part of the global AI supply chain. Notably, SK Hynix recorded a relatively steeper decline as some concerns emerged regarding the potential peaking of demand for AI memory semiconductors.

• KOSPI Decline: Weighed down by the sluggish performance of large-cap semiconductors, which hold a significant market capitalization weight, the KOSPI index closed with a drop of over 1%.
• Sustained Foreign Capital Outflows: As global tech valuation burdens intersect with a broader risk-off sentiment, there is a noticeable outflow of foreign capital from the domestic stock market in pursuit of safer assets.
• Reassessment of Earnings Forecasts: With uncertainties surrounding the global semiconductor industry resurfacing for major players like Samsung Electronics and SK Hynix, the market is undergoing a conservative reassessment of earnings forecasts and target prices for the second half of the year.

Market Outlook and Investment Implications

It is reasonable to interpret the ongoing market correction as a transitional phase where overheated expectations are converging with realistic earnings figures and capital efficiency metrics, rather than a fundamental deterioration or economic crisis. In the near term, global markets are highly likely to exhibit elevated volatility as investors scrutinize big tech's AI return on investment (ROI) metrics alongside key macroeconomic data releases. Therefore, rather than blindly riding short-term price momentum or market trends, it is now imperative for investors to strictly and closely evaluate individual companies' capabilities to generate free cash flow and the visibility of their long-term revenue models.