Optical communications stocks dropped in premarket trading. Applied Optoelectronics fell 12%; AXT and Photonics & Optics ETF fell 5%; Coherent, Lumentum, and Corning fell 4%; Credo Technology, Semtech, and Ciena fell 3%; Fabrinet and POET Technologies fell 2%.

Applied Optoelectronics' stock plunged after the company's plan to raise $600 million through an at-the-market equity offering triggered stock dilution fears.

The optical-networking firm submitted a regulatory filing about the offer after market close on Friday. It detailed that shares would be sold through Raymond James and Needham, and that the proceeds would be used largely for general corporate purposes, including debt repayment, working capital and capital expenditures.

Applied Optoelectronics is among the fastest-growing companies in the optical networking equipment market, a sector that has attracted significant investor interest over the past year.

Hyperscalers are spending record amounts on new data centers, driving demand for optical transceivers, switches and fiber-optic cabling, which offer significant advantages over traditional equipment for high-speed data transmission.