Corning shares tumble on forecast miss

Corning's third-quarter sales forecast has missed Wall Street expectations, causing a significant drop in its stock price. Shares declined by over 16% in premarket trading following the announcement on Tuesday, July 28, 2026. The company, a key supplier of optical fiber products essential for data center construction, is experiencing a slowdown in its typically fast-growing fiber optics division.

This deceleration in fiber optics growth comes at a time when demand for consumer electronics has weakened, affecting the segment that produces Gorilla glass. Despite the recent forecast miss, Corning's stock has demonstrated strong performance over the past two years, with substantial increases in both 2025 and the current year.