The stock market has experienced significant declines this week, with the Nasdaq closing lower and marking its worst week since April. Concerns over high valuations in the tech sector, particularly regarding AI companies, are weighing heavily on investor sentiment. Major tech firms like Nvidia and Palantir have seen sharp drops in their stock prices, contributing to a cumulative loss of nearly $1 trillion in the sector. Amid warnings from bank CEOs about a potential market correction, Wall Street is poised to end its weekly winning streak, reflecting a broader unease over economic indicators and the cooling labor market.