Global stock markets are experiencing a significant sell-off, with major indexes like the Dow Jones and S&P 500 dropping sharply as concerns over high valuations in the tech sector persist. The sell-off is largely driven by apprehension surrounding the upcoming earnings report from Nvidia, a pivotal player in the AI space. Traders are nervous as they weigh potential economic impacts and faltering hopes for a Federal Reserve interest rate cut. Bitcoin and other cryptocurrencies are also feeling the pressure, with bitcoin briefly dipping below $90,000. Investors are reacting to disappointing earnings reports from companies like Home Depot and are hedging against the hype surrounding AI. As fears escalate, Wall Street continues to retreat, leading to one of its worst days in months.