Corning plunges 14% as profit-taking, insider sales trigger rout

Corning Inc. tumbled 14.06% to $221.38 on Wednesday, its steepest single-day drop in recent history, as profit-taking and heavy insider selling triggered a broad technology equipment selloff. The decline erased roughly $27 billion in market value from the specialty glass and ceramics manufacturer, which had been one of the best-performing stocks in the sector this year following its inclusion in major FTSE Russell indexes.

SEC filings from mid-to-late June revealed that Chief Executive Officer Wendell Weeks and multiple senior vice presidents collectively liquidated more than 160,000 shares valued at over $30.7 million near the stock's all-time high, with no offsetting purchases, according to Form 4 disclosures. Over the past three months, a total of 12 insider selling transactions worth approximately $54.1 million were recorded with zero insider purchases — a pattern that shook institutional investor confidence. The absence of buying signaled that company leadership viewed the stock's valuation as disconnected from near-term fundamentals.

The Technology Equipment sector fell 4.13% on Wednesday, with Corning leading the decline. Micron Technology Inc. dropped 9.47%, SanDisk Corp. slid 11.29%, and Nvidia Corp. edged down 0.93%, as selling spread across semiconductor and hardware names. Trading volume in Corning shares surged well above the 20-day average as institutional investors liquidated positions following the stock's inclusion in major FTSE Russell indexes, which had driven mechanical, calendar-driven buying in prior weeks.

Corning's trailing price-to-earnings ratio had soared past 105x, far exceeding its historical averages and the sector median, making the stock highly vulnerable to a sharp unwind. The relative strength index stood at 69.09 before the reversal, suggesting the stock had entered overbought territory, while the Williams %R at 15.557 confirmed the overextended condition. The selloff was further exacerbated by a spike in bearish options activity, with traders snapping up weekly put contracts betting on a correction, according to market data.

Underlying fundamental concerns also weighed on sentiment. The company's second-quarter revenue guidance fell short of Wall Street consensus, while a costly maintenance shutdown at its solar wafer facility is expected to impose an additional $30 million in expenses. Despite the near-term headwinds, long-term optimism remains tied to Corning's high-speed optical fiber partnerships linked to the artificial intelligence infrastructure buildout, which has driven demand for its telecommunications products.

The company, which supplies cover glass for smartphones, optical fiber for telecommunications networks, and display glass for televisions, generated $15.63 billion in annual revenue with a net profit of $1.60 billion. Its market capitalization stood at approximately $190 billion before the decline. Analysts covering the stock maintain an average price target of $209.30, with a high of $230 and a low of $158.87, implying further potential downside from current levels despite a consensus Buy rating.

This article is for informational purposes only and does not constitute investment advice.