Shares of Corning Inc. (GLW) plunged 5.25% in pre-market trading on Wednesday, extending a sharp selloff that began after the optical networking company reported its second-quarter results.

The decline was triggered by the company's third-quarter guidance, which failed to meet elevated investor expectations. While Corning delivered better-than-expected Q2 earnings and revenue, its Q3 core sales guidance of $4.9 billion to $5.0 billion, with a midpoint of $4.95 billion, fell short of the $5.0 billion consensus. This implied a sequential growth deceleration that spooked investors, especially given the stock's strong year-to-date rally and high valuation.

Adding to the pressure, JP Morgan cut its target price on Corning to $170 from $200. The selloff also reflected broader weakness in the optical communications and semiconductor sectors, as profit-taking swept through AI-related stocks. With Corning's shares having surged nearly 100% year-to-date, the in-line guidance left no room for error, triggering large-scale profit-taking.