Corning (NYSE:GLW) shares fell 12% to $145.61 in Monday afternoon trading after the company disclosed an at-the-market equity offering plan of up to $2 billion, designating Goldman Sachs as its sole sales agent. The sell-off made Corning the worst-performing stock in the S&P 500 and dragged down its peers in AI optical connectivity. Coherent (NYSE:COHR) shares dropped 11% to $273.30, Lumentum (NASDAQ:LITE) fell 9% to $843, and Fabrinet (NYSE:FN) declined 6% to $389.69. Additionally, comments from an AI lab over the weekend calling for a slowdown in frontier AI development had an independent impact on the optical connectivity sector.