Applied Materials Inc. (AMAT) experienced a significant pre-market plunge of 5.04%, reflecting a broad sell-off in the semiconductor equipment sector. The decline follows a sharp rally earlier in the week where the stock had surged nearly 9% in a single session, driven by multiple analyst price target upgrades and positive long-term demand commentary from the company's CEO.

The movement is attributed to several factors. Firstly, investors are engaging in profit-taking after the sector's rapid advance, with concerns mounting over the sustainability of the AI chip demand boom that has fueled recent gains. Secondly, noted short seller Michael Burry's public bearish bets on semiconductor stocks have continued to weigh on market sentiment. Finally, fresh geopolitical tensions, specifically renewed U.S.-Iran conflict leading to the closure of the Strait of Hormuz, have dampened overall risk appetite, pressuring chip stocks broadly.

The weakness was not isolated to Applied Materials, with peers like Lam Research and KLA-Tencor also falling over 3% in pre-market trading. The sell-off extended across the semiconductor landscape, including memory chipmakers, as the market braces for the upcoming earnings season which will test the sector's stretched valuations.